研究者紹介システム

松岡 由浩
マツオカ ヨシヒロ
大学院農学研究科 生命機能科学専攻
教授
農学関係
Last Updated :2024/03/16

研究者情報

所属

  • 【主配置】

    大学院農学研究科 生命機能科学専攻
  • 【配置】

    農学部 生命機能科学科

学位

  • 博士(農学), 京都大学
  • 「種間交雑」と「雑種形成」の遺伝メカニズムの研究

授業科目

研究活動

プロフィール情報

研究キーワード

  • 植物遺伝学

研究分野

  • ライフサイエンス / 遺伝学

委員歴

  • 2022年04月, ナショナルバイオリソースプロジェクト(NBRP)・コムギ運営委員会(第5期) 委員長
  • 2017年04月 - 2022年03月, ナショナルバイオリソースプロジェクト(NBRP)・コムギ運営委員会(第4期), 委員長

論文

  • Yoshihiro Matsuoka

    Aegilops tauschii Coss. (DD genome) is a wild paternal progenitor of common wheat (Triticum aestivum L.; AABBDD genome). This species has genetically distinctive intraspecific lineages that differ in their patterns of involvement in allopolyploid speciation of common wheat. Ae. tauschii accessions can cause genome doubling at variable frequencies depending on their genotypes via unreduced gamete production and fusion in the trihaploid F1 hybrids (ABD genome) with Triticum turgidum L. (AABB genome), the maternal progenitor. In this study, we examined the variation patterns of Ae. tauschii’s ability to cause hybrid genome doubling based on an artificial cross experiment and attempted to improve on a previous linkage map of loci that control the expression of this ability by using an increased number of anchor markers. According to the results, this ability was genealogically and geographically widespread within the species, suggesting that it might not have been critically involved in shaping common wheat speciation patterns. The weak phylogeographic structure of the trait variation is consistent with the idea that the genes for hybrid genome doubling have some function (most likely, meiotic) in Ae. tauschii and are maintained because of their adaptive importance, whereas genes may accumulate non-deleterious mutations that could positively or negatively influence the expression of genome doubling when placed in the hybrid genome background. The linkage analysis used 1035 anchor markers and identified five loci on chromosomes 2D, 3D, 6D, and 7D that significantly influenced the expression of hybrid genome doubling.

    2022年, Genetic Resources and Crop Evolution

    [査読有り]

    研究論文(学術雑誌)

  • Mari Gogniashvili, Yoshihiro Matsuoka, Tengiz Beridze

    The aim of the presented study is a genetic characterization of the hexaploid wheat Triticum aestivum L. Two approaches were used for the genealogical study of hexaploid wheats-the complete sequencing of chloroplast DNA and PCR-based haplotype analysis of the fourth intron of Wknox1d and of the fifth-to-sixth-exon region of Wknox1b. The complete chloroplast DNA sequences of 13 hexaploid wheat samples were determined: Free-threshing-T. aestivum subsp. aestivum, one sample; T. aestivum subsp. compactum, two samples; T. aestivum subsp. sphaerococcum, one sample; T. aestivum subsp. carthlicoides, four samples. Hulled-T. aestivum subsp. spelta, three samples; T. aestivum subsp. vavilovii jakubz., two samples. The comparative analysis of complete cpDNA sequences of 20 hexaploid wheat samples (13 samples in this article plus 7 samples sequenced in this laboratory in 2018) was carried out. PCR-based haplotype analysis of the fourth intron of Wknox1d and of the fifth-to-sixth exon region of Wknox1b of all 20 hexaploid wheat samples was carried out. The 20 hexaploid wheat samples (13 samples in this article plus 7 samples in 2018) can be divided into two groups-T. aestivum subsp. spelta, three samples and T. aestivum subsp. vavilovii collected in Armenia, and the remaining 16 samples, including T. aestivum subsp. vavilovii collected in Europe (Sweden). If we take the cpDNA of Chinese Spring as a reference, 25 SNPs can be identified. Furthermore, 13-14 SNPs can be identified in T. aestivum subsp. spelta and subsp. vavilovii (Vav1). In the other samples up to 11 SNPs were detected. 22 SNPs are found in the intergenic regions, 2 found in introns, and 10 SNPs were found in the genes, of which seven are synonymous. PCR-based haplotype analysis of the fourth intron of Wknox1d and the fifth-to-sixth-exon region of Wknox1b provides an opportunity to make an assumption that hexaploid wheats T. aestivum subsp. macha var. palaeocolchicum and var. letshckumicum differ from other macha samples by the absence of a 42 bp insertion in the fourth intron of Wknox1d. One possible explanation for this observation would be that two Aegilops tauschii Coss. (A) and (B) participated in the formation of hexaploids through the D genome: Ae. tauschii (A)-macha (1-5, 7, 8, 10-12), and Ae. tauschii (B)-macha M6, M9, T. aestivum subsp. aestivum cv. 'Chinese Spring' and cv. 'Red Doly'.

    2021年11月24日, International journal of molecular sciences, 22 (23), 英語, 国際誌

    [査読有り]

    研究論文(学術雑誌)

  • Yoshihiro Inoue, Trinh Thi Phuong Vy, Soichiro Asuke, Yoshihiro Matsuoka, Yukio Tosa

    Wheat resistance genes Rwt3 and Rwt4 constitute a host-specificity barrier against non-wheat pathotypes of the blast fungus, Pyricularia oryzae. To understand the origin of these host-specificity resistance genes, we examined their distribution in Aegilops tauschii, a wild wheat progenitor species with the D genome, using synthetic hexaploid lines derived from crosses between Triticum turgidum cv. Langdon and 54 Ae. tauschii accessions, which cover the native ranges and lineages of the species. Infection assays with transformants carrying their corresponding avirulence genes (PWT3 and PWT4) revealed different distribution patterns of the two resistance genes. Rwt3 was present in the TauL1 and TauL2 lineages with wider geographic distribution, while Rwt4 was mainly present in the TauL2 and TauL3 lineages with narrow geographic distribution. Rwt3 and Rwt4 co-occurred exclusively in a TauL2 sublineage that has been suggested to be a probable donor of the D genome to common wheat. This result suggests that Rwt3 and Rwt4 in common wheat is likely to have been derived from Ae. tauschii individual(s) carrying both genes and that the common ancestor of common wheat had both genes when it was established through amphidiploidization.

    2021年07月, Journal of General Plant Pathology, 87 (4), 201 - 208

    [査読有り]

    研究論文(学術雑誌)

  • Soichiro Asuke, Yuta Umehara, Yoshihiro Inoue, Trinh Thi Phuong Vy, Mizuki Iwakawa, Yoshihiro Matsuoka, Kenji Kato, Yukio Tosa

    Avirulence of Eleusine isolates of Pyricularia oryzae on common wheat is conditioned by at least five avirulence genes. One is PWT3 corresponding to resistance gene Rwt3 located on chromosome 1D. We identified a resistance gene corresponding to a second avirulence gene, PWT6, and named it Rmg9 (Rwt6). Rwt6 was closely linked to Rwt3. A survey of the population of Aegilops tauschii, the D genome donor to common wheat, revealed that some accessions from the southern coastal region of the Caspian Sea, the birthplace of common wheat, carried both genes. Rwt6 and Rwt3 carriers accounted for 65% and 80%, respectively, of accessions in a common wheat landrace collection. The most likely explanation of our results is that both resistance genes were simultaneously introduced into common wheat at the time of hybridization of Triticum turgidum and Ae. tauschii. However, a prominent difference was recognized in their geographical distributions in modern wheat; Rwt3 and Rwt6 co-occurred at high frequencies in regions to the east of the Caspian Sea, whereas Rwt6 occurred at a lower frequency than Rwt3 in regions to the west. This difference was considered to be associated with range of pathotypes to which these genes were effective. Ae. tauschii accessions carrying Rwt3 and Rwt6 also carried Rwt4, another resistance gene involved in the species specificity. We suggest that the gain of the D genome should have given an adaptive advantage to the genus Triticum by conferring disease resistance.

    2021年05月19日, Phytopathology, 111 (11), PHYTO02210080R - 2029, 英語, 国際誌

    [査読有り]

    研究論文(学術雑誌)

  • Mazin Mahjoob Mohamed Mahjoob, Tai-Shen Chen, Yasir Serag Alnor Gorafi, Yuji Yamasaki, Nasrein Mohamed Kamal, Mostafa Abdelrahman, Hiroyoshi Iwata, Yoshihiro Matsuoka, Izzat Sidahmed Ali Tahir, Hisashi Tsujimoto

    Aegilops tauschii Coss., the D genome donor of hexaploid wheat (Triticum aestivum L.), is the most promising resource used to broaden the genetic diversity of wheat. Taxonomical studies have classified Ae. tauschii into two subspecies, ssp. tauschii and ssp. strangulata. However, molecular analysis revealed three distantly related lineages, TauL1, TauL2 and TauL3. TauL1 and TauL3 includes the only ssp. tauschii, whereas TauL2 includes both subspecies. This study aimed to clarify the phylogeny of Ae. tauschii and to find the traits that can differentiate between TauL1, TauL2 and TauL3, or between ssp. tauschii and ssp. strangulata. We studied the genetic and morpho-physiological diversity in 293 accessions of Ae. tauschii, covering the entire range of the species. A total of 5880 high-quality SNPs derived from DArTseq were used for phylogenetic cluster analyses. As a result, we observed wide morpho-physiological variation in each lineage and subspecies. Despite this variation, no key traits can discriminate lineages or subspecies though some traits were significantly different. Of 124 accessions previously lacking the passport data, 66 were allocated to TauL1, 57 to TauL2, and one to TauL3.

    MDPI, 2021年05月, DIVERSITY-BASEL, 13 (5), 英語

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    研究論文(学術雑誌)

  • Mazin Mahjoob Mohamed Mahjoob, Yasir Serag Alnor Gorafi, Nasrein Mohamed Kamal, Yuji Yamasaki, Izzat Sidahmed Ali Tahir, Yoshihiro Matsuoka, Hisashi Tsujimoto

    Aegilops tauschii, the D-genome donor of bread wheat, is a storehouse of genetic diversity that can be used for wheat improvement. This species consists of two main lineages (TauL1 and TauL2) and one minor lineage (TauL3). Its morpho-physiological diversity is large, with adaptations to a wide ecological range. Identification of allelic diversity in Ae. tauschii is of utmost importance for efficient breeding and widening of the genetic base of wheat. This study aimed at identifying markers or genes associated with morpho-physiological traits in Ae. tauschii, and at understanding the difference in genetic diversity between the two main lineages. We performed genome-wide association studies of 11 morpho-physiological traits of 343 Ae. tauschii accessions representing the entire range of habitats using 34,829 DArTseq markers. We observed a wide range of morpho-physiological variation among all accessions. We identified 23 marker-trait associations (MTAs) in all accessions, 15 specific to TauL1 and eight specific to TauL2, suggesting independent evolution in each lineage. Some of the MTAs could be novel and have not been reported in bread wheat. The markers or genes identified in this study will help reveal the genes controlling the morpho-physiological traits in Ae. tauschii, and thus in bread wheat even if the plant morphology is different.

    MDPI, 2021年02月, PLANTS-BASEL, 10 (2), 英語

    [査読有り]

    研究論文(学術雑誌)

  • Yoshihiro Matsuoka, Naoki Mori

    Wiley, 2020年12月, Ecology and Evolution, 10 (24), 13926 - 13937

    [査読有り]

    研究論文(学術雑誌)

  • Masahiro Kishii, Julio Huerta, Hisashi Tsujimoto, Yoshihiro Matsuoka

    Studies on natural plant variability for biotic (e.g. disease) and abiotic (e.g. drought) stress resistance/tolerance may provide valuable insights into the use of wild genetic resources for breeding purposes, as such phenotypes are often the product of local adaption. To elucidate the mechanisms underlying stripe rust resistance in wild wheat Aegilops tauschii Coss., the D genome progenitor of common wheat (Triticum aestivum L., AABBDD genome), we studied the distribution of stripe rust resistant accessions among the intraspecific lineages that were found previously through DNA polymorphism analysis (TauL1, TauL2, and TauL3) and the expression of resistance in synthetic allohexaploid lines (AABBDD genome) derived from an artificial cross between Ae. tauschii and a cultivar of Triticum turgidum L., the AB genome progenitor of common wheat. Forty-two, out of the 104 Ae. tauschii representative accessions, showed resistance in a field test. The resistant accessions were from Armenia, Azerbaijan, Iran, and Turkmenistan, and belonged to TauL1 (five accessions) and TauL2 (37 accessions). Most TauL1 and TauL2 accessions parental to the synthetic lines showed resistance in the seedling inoculation tests. Thus, TauL1 and TauL2 lineages may be sources of stripe rust resistance for common wheat improvement. In contrast, virtually all synthetic lines examined (32 lines in total), including 22 lines derived from the resistant TauL2 accessions, were susceptible under field conditions, indicating that field resistance of Ae. tauschii to stripe rust may not be inherited in the synthetic offspring. Seedling inoculation tests showed that the synthetic lines are mostly susceptible, but five had weak resistance.

    SPRINGER, 2019年04月, GENETIC RESOURCES AND CROP EVOLUTION, 66 (4), 909 - 920, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Yoshihiro Matsuoka, Shigeo Takumi

    The ability to cause reproductive isolation often varies among individuals within a plant species. We addressed whether such polymorphism influenced speciation of the allopolyploid common wheat (Triticum aestivum L., AABBDD genome) by evaluating the expression of pre-pollination (outcrossing potential) and post-pollination (crossability) barriers in Aegilops tauschii Coss. (the D genome progenitor). In total, 201 Ae. tauschii accessions representing the entire natural habitat range of the species were used for anther length measurement and artificial crosses with a Triticum turgidum L. (the AB genome progenitor) tester. Intraspecific comparisons showed that both barriers were more strongly expressed in the TauL1 lineage than in the TauL2 lineage. The ability of Ae. tauschii to cause reproductive isolation in the hybridisation with T. turgidum might have markedly influenced common wheat's speciation by inducing lineage-associated patterns of gene flow. The TauL2 accessions with high potential for natural hybridisation with T. turgidum clustered in the southern coastal Caspian region. This provided phenotypic support for the derivation of the D genome of common wheat from southern Caspian populations. The present study underscored the importance of approaches that incorporate the genealogical and geographic structure of the parental species' reproductive isolation in understanding the mechanism of plant allopolyploid speciation.

    Nature Publishing Group, 2017年12月01日, Scientific Reports, 7 (1), 英語

    [査読有り]

    研究論文(学術雑誌)

  • Daisuke Saisho, Shigeo Takumi, Yoshihiro Matsuoka

    Adaptation to edaphic stress may have a key role in plant species range expansion. Aegilops tauschii Coss., the common wheat's D-genome progenitor native to the Transcaucasus-Middle East region, is a good model to study the relationships between soil salinity and plant distributions: one of its intraspecific sublineages, TauL1b, drove the long-distance eastward expansion of this species range reaching semi-arid-central Asia. Salt tolerance during germination and seedling growth was evaluated in 206 Ae. tauschii accessions by treating seeds with NaCl solutions differing in concentrations. Differences in natural variation patterns were analyzed between sublineages and associated with natural edaphic condition variables, and then compared with reproductive trait variation patterns. The natural variations observed in NaCl-induced-stress tolerance had clear geographic and genetic structure. Seedling growth significantly increased in the TauL1b accessions that were collected from salt-affected soil habitats, whereas germinability did not. Principal component analysis suggested that the NaCl-induced-stress tolerances and reproductive traits might have had a similar degree of influence on Ae. tauschii's eastward range expansion. Adaptation to salt-affected soils through increased seedling growth was an important factor for the species' successful colonization of the semi-arid central Asian habitats. TauL1b accessions might provide useful genetic resources for salt-tolerant wheat breeds.

    Nature Publishing Group, 2016年12月08日, Scientific Reports, 6, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Yoshihiro Matsuoka, Shigeo Takumi, Taihachi Kawahara

    Background: How species ranges form in landscapes is a matter of long-standing evolutionary interest. However, little is known about how natural phenotypic variations of ecologically important traits contribute to species range expansion. In this study, we examined the phylogeographic patterns of phenotypic changes in life history (seed production) and phenological (flowering time) traits during the range expansion of Aegilops tauschii Coss. from the Transcaucasus and Middle East to central Asia. Results: Our comparative analyses of the patterns of natural variations for those traits and their association with the intraspecific lineage structure showed that (1) the eastward expansion to Asia was driven by an intraspecific sublineage (named TauL1b), (2) high seed production ability likely had an important role at the initial dispersal stage of TauL1b's expansion to Asia, and (3) the phenological change to early flowering phenotypes was one of the key adaptation events for TauL1b to further expand its range in Asia. Conclusions: This study provides for the first time a broad picture of the process of Ae. tauschii's eastward range expansion in which life history and phenological traits may have had respective roles in its dispersal and adaptation in Asia. The clear association of seed production and flowering time patterns with the intraspecific lineage divergence found in this study invites further genetic research to bring the mechanistic understanding of the changes in these key functional traits during range expansion within reach.

    BioMed Central Ltd., 2015年09月30日, BMC Evolutionary Biology, 15 (1), 英語

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    研究論文(学術雑誌)

  • Ryo Nishijima, Julio C. M. Iehisa, Yoshihiro Matsuoka, Shigeo Takumi

    Background: Cuticular wax production on plant surfaces confers a glaucous appearance and plays important roles in plant stress tolerance. Most common wheat cultivars, which are hexaploid, and most tetraploid wheat cultivars are glaucous in contrast, a wild wheat progenitor, Aegilops tauschii, can be glaucous or non-glaucous. A dominant non-glaucous allele, Iw2, resides on the short arm of chromosome 2D, which was inherited from Ae. tauschii through polyploidization. Iw2 is one of the major causal genes related to variation in glaucousness among hexaploid wheat. Detailed genetic and phylogeographic knowledge of the Iw2 locus in Ae. tauschii may provide important information and lead to a better understanding of the evolution of common wheat.Results: Glaucous Ae. tauschii accessions were collected from a broad area ranging from Armenia to the southwestern coastal part of the Caspian Sea. Linkage analyses with five mapping populations showed that the glaucous versus non-glaucous difference was mainly controlled by the Iw2 locus in Ae. tauschii. Comparative genomic analysis of barley and Ae. tauschii was then used to develop molecular markers tightly linked with Ae. tauschii Iw2. Chromosomal synteny around the orthologous Iw2 regions indicated that some chromosomal rearrangement had occurred during the genetic divergence leading to Ae. tauschii, barley, and Brachypodium. Genetic associations between specific Iw2-linked markers and respective glaucous phenotypes in Ae. tauschii indicated that at least two non-glaucous accessions might carry other glaucousness-determining loci outside of the Iw2 locus.Conclusion: Allelic differences at the Iw2 locus were the main contributors to the phenotypic difference between the glaucous and non-glaucous accessions of Ae. tauschii. Our results supported the previous assumption that the D-genome donor of common wheat could have been any Ae. tauschii variant that carried the recessive iw2 allele.

    BioMed Central Ltd., 2014年09月16日, BMC Plant Biology, 14 (1), 英語

    [査読有り]

    研究論文(学術雑誌)

  • Yoshihiro Matsuoka, Shigeo Takumi, Shuhei Nasuda

    Polyploidy, which arises through complex genetic and ecological processes, is an important mode of plant speciation. This review provides an overview of recent advances in understanding why plant polyploid species are so ubiquitous and diverse. We consider how the modern framework for understanding genetic mechanisms of speciation could be used to study allopolyploid speciation that occurs through hybrid genome doubling, that is, whole genome doubling of interspecific F1 hybrids by the union of male and female unreduced gametes. We outline genetic and ecological mechanisms that may have positive or negative impacts on the process of allopolyploid speciation through hybrid genome doubling. We also discuss the current status of studies on the underlying genetic mechanisms focusing on the wheat (Triticum and Aegilops) hybrid-specific reproductive phenomena that are well known but deserve renewed attention from an evolutionary viewpoint. © 2014 Elsevier Inc.

    2014年, International Review of Cell and Molecular Biology, 309, 199 - 258, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Yoshihiro Matsuoka, Shuhei Nasuda, Yasuyo Ashida, Miyuki Nitta, Hisashi Tsujimoto, Shigeo Takumi, Taihachi Kawahara

    The complex process of allopolyploid speciation includes various mechanisms ranging from species crosses and hybrid genome doubling to genome alterations and the establishment of new allopolyploids as persisting natural entities. Currently, little is known about the genetic mechanisms that underlie hybrid genome doubling, despite the fact that natural allopolyploid formation is highly dependent on this phenomenon. We examined the genetic basis for the spontaneous genome doubling of triploid F1 hybrids between the direct ancestors of allohexaploid common wheat (Triticum aestivum L., AABBDD genome), namely Triticumturgidum L. (AABB genome) and Aegilopstauschii Coss. (DD genome). An Ae. tauschii intraspecific lineage that is closely related to the D genome of common wheat was identified by population-based analysis. Two representative accessions, one that produces a high-genome-doubling-frequency hybrid when crossed with a T. turgidum cultivar and the other that produces a low-genome-doubling-frequency hybrid with the same cultivar, were chosen from that lineage for further analyses. A series of investigations including fertility analysis, immunostaining, and quantitative trait locus (QTL) analysis showed that (1) production of functional unreduced gametes through nonreductional meiosis is an early step key to successful hybrid genome doubling, (2) first division restitution is one of the cytological mechanisms that cause meiotic nonreduction during the production of functional male unreduced gametes, and (3) six QTLs in the Ae. tauschii genome, most of which likely regulate nonreductional meiosis and its subsequent gamete production processes, are involved in hybrid genome doubling. Interlineage comparisons of Ae. tauschii's ability to cause hybrid genome doubling suggested an evolutionary model for the natural variation pattern of the trait in which non-deleterious mutations in six QTLs may have important roles. The findings of this study demonstrated that the genetic mechanisms for hybrid genome doubling could be studied based on the intrinsic natural variation that exists in the parental species.

    2013年, PloS one, 8 (8), e68310, 英語, 国際誌

    [査読有り]

    研究論文(学術雑誌)

  • Quahir Sohail, Tomoe Inoue, Hiroyuki Tanaka, Amin Elsadig Eltayeb, Yoshihiro Matsuoka, Hisashi Tsujimoto

    Few genes are available to develop drought-tolerant bread wheat (Triticum aestivum L.) cultivars. One way to enhance bread wheat's genetic diversity would be to take advantage of the diversity of wild species by creating synthetic hexaploid wheat (SW) with the genomic constitution of bread wheat. In this study, we compared the expression of traits encoded at different ploidy levels and evaluated the applicability of Aegilops tauschii drought-related traits using 33 Ae. tauschii accessions along with their corresponding SW lines under well-watered and drought conditions. We found wide variation in Ae. tauschii, and even wider variation in the SW lines. Some SW lines were more drought-tolerant than the standard cultivar Cham 6. Aegilops tauschii from some regions gave better performing SW lines. The traits of Ae. tauschii were not significantly correlated with their corresponding SW lines, indicating that the traits expressed in wild diploid relatives of wheat may not predict the traits that will be expressed in SW lines derived from them. We suggest that, regardless of the adaptability and performance of the Ae. tauschii under drought, production of SW could probably result in genotypes with enhanced trait expression due to gene interactions, and that the traits of the synthetic should be evaluated in hexaploid level.

    2011年12月, Breeding science, 61 (4), 347 - 57, 英語, 国内誌

    [査読有り]

    研究論文(学術雑誌)

  • Yoshihiro Matsuoka

    The evolution of the polyploid Triticum wheats is distinctive in that domestication, natural hybridization and allopolyploid speciation have all had significant impacts on their diversification. In this review, I outline the phylogenetic relationships of cultivated wheats and their wild relatives and provide an overview of the recent progress and remaining issues in understanding the genetic and ecological factors that favored their evolution. An attempt is made to view the evolution of the polyploid Triticum wheats as a continuous process of diversification that was initiated by domestication of tetraploid emmer wheat and driven by various natural events ranging from interploidy introgression via hybridization to allopolyploid speciation of hexaploid common wheat, instead of viewing it as a group of discrete evolutionary processes that separately proceeded at the tetraploid and hexaploid levels. This standpoint underscores the important role of natural hybridization in the reticulate diversification of the tetraploid-hexaploid Triticum wheat complex and highlights critical, but underappreciated, issues that concern the allopolyploid speciation of common wheat.

    2011年05月, Plant & cell physiology, 52 (5), 750 - 64, 英語, 国内誌

    [査読有り]

    研究論文(学術雑誌)

  • Nobuyuki Mizuno, Masanori Yamasaki, Yoshihiro Matsuoka, Taihachi Kawahara, Shigeo Takumi

    Aegilops tauschii Coss. is the D-genome progenitor of hexaploid wheat. Aegilops tauschii, a wild diploid species, has a wide natural species range in central Eurasia, spreading from Turkey to western China. Amplified fragment length polymorphism (AFLP) analysis using a total of 122 accessions of Ae. tauschii was conducted to clarify the population structure of this widespread wild wheat species. Phylogenetic and principal component analyses revealed two major lineages in Ae. tauschii. Bayesian population structure analyses based on the AFLP data showed that lineages one (L1) and two (L2) were respectively significantly divided into six and three sublineages. Only four out of the six L1 sublineages were diverged from those of western habitats in the Transcaucasia and northern Iran region to eastern habitats such as Pakistan and Afghanistan. Other sublineages including L2 were distributed to a limited extent in the western region. Subspecies strangulata seemed to be differentiated in one sublineage of L2. Among three major haplogroups (HG7, HG9 and HG16) previously identified in the Ae. tauschii population based on chloroplast variation, HG7 accessions were widely distributed to both L1 and L2, HG9 accessions were restricted to L2, and HG16 accessions belonged to L1, suggesting that HG9 and HG16 were formed from HG7 after divergence of the first two lineages of the nuclear genome. These results on the population structure of Ae. tauschii and the genealogical relationship among Ae. tauschii accessions should provide important agricultural and evolutionary knowledge on genetic resources and conservation of natural genetic diversity. © 2010 Blackwell Publishing Ltd.

    2010年03月, Molecular Ecology, 19 (5), 999 - 1013, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Yoshihiro Matsuoka, Emi Nishioka, Taihachi Kawahara, Shigeo Takumi

    The genealogical and geographic structure of variation in spikelet morphology was analyzed for central Eurasian wild wheat Aegilops tauschii Coss. using a diverse array of 203 sample accessions that represented the entire species range. In this sample set, two subspecies were identified on the basis of sensu-stricto criteria: only the accessions having markedly moniliform spikes were assigned to Ae. tauschii Coss. subspecies strangulata (Eig) Tzvel., whereas those having mildly moniliform and cylindrical spikes to Ae. tauschii Coss. subspecies tauschii. In a graph of the first two axes from a principal component analysis based on nine spikelet traits, the plots of the two subspecies formed separate clusters, indicating that subspecies strangulata sens. str. is a practically usable taxon. Chloroplast-DNA-based genealogical analyses suggested that subspecies strangulata diverged from an ancestor that carried a specific chloroplast DNA type, whereas, after divergence, this subspecies became polyphyletic, likely through hybridization. Geographically, significant longitudinal and latitudinal clines were detected for spikelet size, with spikelets tending to be small in the eastern and southern regions. These results shed some light on the patterns of subspecies divergence and spikelet-shape diversification in the course of Ae. tauschii's long-distance dispersal from the Transcaucasus to China. © 2009 Springer-Verlag.

    2009年05月, Plant Systematics and Evolution, 279 (1-4), 233 - 244, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Shigeo Takumi, Emi Nishioka, Haruhiko Morihiro, Taihachi Kawahara, Yoshihiro Matsuoka

    Aegilops tauschii Coss. (syn Ae. squarrosa L.) is a wild diploid wheat species. It has a wide natural species range in central Eurasia, spreading from northern Syria and Turkey to western China. Ae. tauschii is known as the D genome progenitor of hexaploid bread wheat. The genealogical and geographical structure of variation of morphological traits was analyzed using a diverse array of 205 sample accessions that represented the entire species range. In total, 27 traits, including anther and pistil shape and internode length, were examined in this study. Large-scale natural variation was found for all examined traits. Geographically, significant longitudinal clines were detected for anther size, internode length and spike size and shape. Anthers tended to be small in accessions from the eastern region. Internodes also tended to be short, whereas spikes tended to be long in accessions from the eastern region. Spikelet density per spike tended to be high in the eastern habitats. In the process of west-to-east dispersal, Ae. tauschii underwent extensive morphological, genetic and ecological diversification that produced the variation seen among today's natural populations.

    2009年, Breeding Science, 59 (5), 579 - 588, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Yves Vigouroux, Jeffrey C Glaubitz, Yoshihiro Matsuoka, Major M Goodman, Jesús Sánchez G, John Doebley

    Because of the economic importance of maize and its scientific importance as a model system for studies of domestication, its evolutionary history is of general interest. We analyzed the population genetic structure of maize races by genotyping 964 individual plants, representing almost the entire set of ∼350 races native to the Americas, with 96 microsatellites. Using Bayesian clustering, we detected four main clusters consisting of highland Mexican, northern United States (US), tropical lowland, and Andean races. Phylogenetic analysis indicated that the southwestern US was an intermediary stepping stone between Mexico and the northern US. Furthermore, southeastern US races appear to be of mixed northern flint and tropical lowland ancestry, while lowland middle South American races are of mixed Andean and tropical lowland ancestry. Several cases of post-Columbian movement of races were detected, most notably from the US to South America. Of the four main clusters, the highest genetic diversity occurs in highland Mexican races, while diversity is lowest in the Andes and northern US. Isolation by distance appears to be the main factor underlying the historical diversification of maize. We identify highland Mexico and the Andes as potential sources of genetic diversity underrepresented among elite lines used in maize breeding programs.

    2008年10月, American journal of botany, 95 (10), 1240 - 53, 英語, 国際誌

    [査読有り]

    研究論文(学術雑誌)

  • Yoshihiro Matsuoka, Shigeo Takumi, Taihachi Kawahara

    Timing of flowering is a reproductive trait that has significant impact on fitness in plants. In contrast to recent advances in understanding the molecular basis of floral transition, few empirical studies have addressed questions concerning population processes of flowering time diversification within species. We analyzed chloroplast DNA genealogical structure of flowering time variation in central Eurasian wild wheat Aegilops tauschii Coss. using 200 accessions that represent the entire species range. Flowering time measured as days from germination to flowering varied from 144.0 to 190.0 days (average 161.3 days) among accessions in a common garden/greenhouse experiment. Subsequent genealogical and statistical analyses showed that (1) there exist significant longitudinal and latitudinal clines in flowering time at the species level, (2) the early-flowering phenotype evolved in two intraspecific lineages, (3) in Asia, winter temperature was an environmental factor that affected the longitudinal clinal pattern of flowering time variation, and (4) in Transcaucasus-Middle East, some latitudinal factors affected the geographic pattern of flowering time variation. On the basis of palaeoclimatic, biogeographic, and genetic evidence, the northern part of current species' range [which was within the temperate desert vegetation (TDV) zone at the Last Glacial Maximum] is hypothesized to have harbored species refugia. Postglacial southward dispersal from the TDV zone seems to have been driven by lineages that evolved short-flowering-time phenotypes through different genetic mechanisms in Transcaucasus-Middle East and Asia. © 2008 Matsuoka et al.

    2008年09月04日, PLoS ONE, 3 (9), 英語

    [査読有り]

    研究論文(学術雑誌)

  • Yoshihiro Matsuoka, Mohammad Jaffar Aghaei, Mohammad Reza Abbasi, Abdolhosain Totiaei, Javad Mozafari, Shoji Ohta

    Springer Science and Business Media LLC, 2008年09月, Genetic Resources and Crop Evolution, 55 (6), 861 - 868

    [査読有り]

    研究論文(学術雑誌)

  • Evolutionary dynamics of wheat mitochondrial gene structure with special remarks on the origin and effects of RNA editing in cereals.

    Koichiro Tsunewaki, Yoshihiro Matsuoka, Yukiko Yamazaki, Yasunari Ogihara

    We investigated the evolutionary dynamics of wheat mitochondrial genes with respect to their structural differentiation during organellar evolution, and to mutations that occurred during cereal evolution. First, we compared the nucleotide sequences of three wheat mitochondrial genes to those of wheat chloroplast, alpha-proteobacterium and cyanobacterium orthologs. As a result, we were able to (1) differentiate the conserved and variable segments of the orthologs, (2) reveal the functional importance of the conserved segments, and (3) provide a corroborative support for the alpha-proteobacterial and cyanobacterial origins of those mitochondrial and chloroplast genes, respectively. Second, we compared the nucleotide sequences of wheat mitochondrial genes to those of rice and maize to determine the types and frequencies of base changes and indels occurred in cereal evolution. Our analyses showed that both the evolutionary speed, in terms of number of base substitutions per site, and the transition/transversion ratio of the cereal mitochondrial genes were less than two-fifths of those of the chloroplast genes. Eight mitochondrial gene groups differed in their evolutionary variability, RNA and Complex I (nad) genes being most stable whereas Complex V (atp) and ribosomal protein genes most variable. C-to-T transition was the most frequent type of base change; C-to-G and G-to-C transversions occurred at lower rates than all other changes. The excess of C-to-T transitions was attributed to C-to-U RNA editing that developed in early stage of vascular plant evolution. On the contrary, the editing of C residues at cereal T-to-C transition sites developed mostly during cereal divergence. Most indels were associated with short direct repeats, suggesting intra- and intermolecular recombination as an important mechanism for their origin. Most of the repeats associated with indels were di- or trinucleotides, although no preference was noticed for their sequences. The maize mt genome was characterized by a high incidence of indels, comparing to the wheat and rice mt genomes.

    2008年08月, Genes & genetic systems, 83 (4), 301 - 20, 英語, 国内誌

    [査読有り]

    研究論文(学術雑誌)

  • [Molecular phylogenetics of cultivated plants, with special reference to maize and common wheat].

    Yoshihiro Matsuoka

    2007年12月, Tanpakushitsu kakusan koso. Protein, nucleic acid, enzyme, 52 (15), 1937 - 41, 日本語, 国内誌

    研究論文(学術雑誌)

  • Yoshihiro Matsuoka, Shigeo Takumi, Taihachi Kawahara

    The tempo, mode, and geography of allopolyploid speciation are influenced by natural variation in the ability of parental species to express postzygotic reproductive phenotypes that affect hybrid fertility. To shed light on the impact of such natural variations, we used allohexaploid Triticum aestivum wheats' evolution as a model and analyzed the geographic and phylogenetic distributions of Aegilops tauschii (diploid progenitor) accessions involved in the expression of abnormality and fertility in triploid F1 hybrids with Triticum turgidum (tetraploid progenitor). Artificial-cross experiments and chloroplast-DNA-based evolutionary analyses showed that hybrid-abnormality- causing accessions had limited geographic and phylogenetic distributions, indicative that postzygotic hybridization barriers are underdeveloped between these species. In contrast, accessions that are involved with fertile triploid F1 hybrid formation have wide geographic and phylogenetic distributions, indicative of a deep evolutionary origin. Wide-spread hybrid-fertilizing accessions support the theory that T. aestivum speciation occurred at multiple sites within the species range of Ae. tauschii, in which existing conditions enabled natural hybridization with T. turgidum. Implications of our findings on how natural variation in the ability of Ae. tauschii to express those postzygotic reproductive phenotypes diversified and contributed to the speciation of T. aestivum are discussed. © 2007 Springer-Verlag.

    2007年08月, Theoretical and Applied Genetics, 115 (4), 509 - 518, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Yoshihiro Matsuoka, Naoki Mori, Taihachi Kawahara

    Intraspecific patterns of chloroplast DNA variation was studied in Aegilops tauschii Coss., the D-genome progenitor of bread wheat. Nucleotide sequences of ten chloroplast microsatellite loci were analyzed for 63 accessions that cover the central part of the species distribution. As is often the case with nuclear microsatellites, those of chloroplasts of Ae. tauschii bear complex mutations. Several types of mutations other than change in the microsatellite repeat number were found, including base substitutions and length mutations in flanking regions. In total, eight mutations were present in the flanking regions of four loci. Most mutations in the flanking regions of microsatellite repeats are associated with biallelic polymorphisms. Phylogeographic analyses showed that such biallelic polymorphisms are useful to investigate intraspecific patterns of monophyletic lineage divergence. In contrast, most microsatellite repeat sites are multiallelic, variable within intraspecific lineages, and useful to compare degrees of genetic diversity between lineages. These findings show that the chloroplast genome harbors evolutionary variations informative for intraspecific studies of Ae. tauschii and can be analyzed by genealogical approaches. © Springer-Verlag 2005.

    2005年07月, Theoretical and Applied Genetics, 111 (2), 265 - 271, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Kenji Fukunaga, Jason Hill, Yves Vigouroux, Yoshihiro Matsuoka, Jesus Sanchez G., Kejun Liu, Edward S. Buckler, John Doebley

    The teosintes, the closest wild relatives of maize, are important resources for the study of maize genetics and evolution and for plant breeding. We genotyped 237 individual teosinte plants for 93 microsatellites. Phylogenetic relationships among species and subspecific taxa were largely consistent with prior analyses for other types of molecular markers. Plants of all species formed monophyletic clades, although relationships among species were not fully resolved. Phylogenetic analysis indicated that the Mexican annual teosintes divide into two clusters that largely correspond to the previously defined subspecies, Z. mays ssp. parviglumis and ssp. mexicana, although there are a few samples that represent either evolutionary intermediates or hybrids between these two subspecies. The Mexican annual teosintes show genetic substructuring along geographic lines. Hybridization or introgression between some teosintes and maize occurs at a low level and appears most common with Z. mays ssp. mexicana. Phylogeographic and phylogenetic analyses of the Mexican annual teosintes indicated that ssp. parviglumis diversified in the eastern part of its distribution and spread from east to west and that ssp. mexicana diversified in the Central Plateau of Mexico and spread along multiple paths to the north and east. We defined core sets of collections of Z. mays ssp. mexicana and ssp. parviglumis that attempt to capture the maximum number of microsatellite alleles for given sample sizes. Copyright © 2005 by the Genetics Society of America.

    2005年04月, Genetics, 169 (4), 2241 - 2254, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Yves Vigouroux, Sharon Mitchell, Yoshihiro Matsuoka, Martha Hamblin, Stephen Kresovich, J. Stephen C. Smith, Jennifer Jaqueth, Oscar S. Smith, John Doebley

    How domestication bottlenecks and artificial selection shaped the amount and distribution of genetic variation in the genomes of modern crops is poorly understood. We analyzed diversity at 462 simple sequence repeats (SSRs) or microsatellites spread throughout the maize genome and compared the diversity observed at these SSRs in maize to that observed in its wild progenitor, teosinte. The results reveal a modest genome-wide deficit of diversity in maize relative to teosinte. The relative deficit of diversity is less for SSRs with dinucleotide repeat motifs than for SSRs with repeat motifs of more than two nucleotides, suggesting that the former with their higher mutation rate have partially recovered from the domestication bottleneck. We analyzed the relationship between SSR diversity and proximity to QTL for domestication traits and observed no relationship between these factors. However, we did observe a weak, although significant, spatial correlation for diversity statistics among SSRs within 2 cM of one another, suggesting that SSR diversity is weakly patterned across the genome. Twenty-four of 462 SSRs (5%) show some evidence of positive selection in maize under multiple tests. Overall, the pattern of genetic diversity at maize SSRs can be explained largely by a bottleneck effect with a smaller effect from selection. Copyright © 2005 by the Genetics Society of America.

    2005年03月, Genetics, 169 (3), 1617 - 1630, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Yoshihiro Matsuoka, Shuhei Nasuda

    Hexaploid bread wheat was derived from a hybrid cross between a cultivated form of tetraploid Triticum wheat (female progenitor) and a wild diploid species, Aegilops tauschii Coss. (male progenitor). This cross produced a fertile triploid F1 hybrid that set hexaploid seeds. The identity of the female progenitor is unknown, but various cultivated tetraploid Triticum wheats exist today. Genetic and archaeological evidence suggests that durum wheat (T. turgidum ssp. durum) may be the female progenitor. In previous studies, however, F1 hybrids of durum wheat crossed with Ae. tauschii consistently had low levels of fertility. To establish an empirical basis for the theory of durum wheat being the female progenitor of bread wheat, we crossed a durum wheat cultivar that carries a gene for meiotic restitution with a line of Ae. tauschii. F1 hybrids were produced without using embryo rescue techniques. These triploid F1 hybrids were highly fertile and spontaneously set hexaploid F2 seeds at the average selfed seedset rate of 51.5%. To the best of our knowledge, this is the first example of the production of highly fertile F1 hybrids between durum wheat and Ae. tauschii. The F1 and F2 hybrids are both similar morphologically to bread wheat and have vigorous growth habits. Cytological analyses of F1 male gametogenesis showed that meiotic restitution is responsible for the high fertility of the triploid F1 hybrids. The implications of these findings for the origin of bread wheat are discussed. © Springer-Verlag 2004.

    2004年11月, Theoretical and Applied Genetics, 109 (8), 1710 - 1717, 英語

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    研究論文(学術雑誌)

  • Yves Vigouroux, Yoshihiro Matsuoka, John Doebley

    Directional evolution in microsatellites is the tendency for microsatellites either to increase or to decrease in size over time between populations. We analyzed 99 microsatellite loci in a sample of 193 maize plants representing the entire pre-Columbian range of this crop for evidence of directional evolution. We took advantage of the known phylogeographic history of maize with the independent movement of maize from its ancestral location in Mexico to North and South America. We show that there is an increase in the average allele size of microsatellites in the geographically derived North and South American groups relative to the ancestral Mexican group. We also show that there is a negative correlation between average allele size and altitude in all three groups. Directional evolution in maize microsatellites can be explained by changes in the mutation rate over time and space, changes in the degree of mutational bias to a larger allele, demographic differences between the ancestral and geographically derived populations, and/or scenarios involving selection on microsatellite size. The occurrence of directional evolution for microsatellite size indicates that the estimation of population parameters with microsatellite data in maize should be done with caution.

    2003年09月01日, Molecular Biology and Evolution, 20 (9), 1480 - 1483, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Koichiro Tsunewaki, Gui-Zhi Wang, Yoshihiro Matsuoka

    This article comprises our final remarks on the phenotypic effects of alien plasmons on common wheat. Twenty-one vegetative, reproductive, and seed characters of 551 alloplasmic lines of 12 common wheat genotypes with 46 alloplasmons, and as the control, their euplasmic lines were investigated. Effects of genotype, plasmon, and their interaction had high statistical significance for all the characters investigated, whereas phenotypic variations attributable to the alien plasmons were relatively small. Individual plasmon types are characterized by their primary effects on 21 characters. Genotype x plasmon effects on two representative characters, heading date and plant height, are described in detail. Cluster and principal component analyses of the phenotypic effects of the 47 plasmons yielded 22 groups. The relationships between these phenotype-based groups and those defined by molecular differences in organellar genomes were examined. A significant correlation was found with some explainable discrepancies. For efficient plasmon identification, use of six of the present 12 genotypes is proposed. The key for plasmon classification is provided. Our findings indicate that alien plasmons may be of limited value in future wheat breeding, but that the plasmon diversity that exists in Triticum and Aegilops species is of great significance for understanding the evolution of these genera.

    2002年12月, Genes and Genetic Systems, 77 (6), 409 - 427, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Yoshihiro Matsuoka, Yukiko Yamazaki, Yasunari Ogihara, Koichiro Tsunewaki

    The fully sequenced chloroplast genomes of maize (subfamily Panicoideae), rice (subfamily Bambusoideae), and wheat (subfamily Pooideae) provide the unique opportunity to investigate the evolution of chloroplast genes and genomes in the grass family (Poaceae) by whole-genome comparison. Analyses of nucleotide sequence variations in 106 cereal chloroplast genes with tobacco sequences as the outgroup suggested that (1) most of the genic regions of the chloroplast genomes of maize, rice, and wheat have evolved at similar rates (2) RNA genes have highly conservative evolutionary rates relative to the other genes (3) photosynthetic genes have been under strong purifying selection (4) between the three cereals, 14 genes which account for about 28% of the genic region have evolved with heterogeneous nucleotide substitution rates and (5) rice genes tend to have evolved more slowly than the others at loci where rate heterogeneity exists. Although the mechanism that underlies chloroplast gene diversification is complex, our analyses identified variation in nonsynonymous substitution rates as a genetic force that generates heterogeneity, which is evidence of selection in chloroplast gene diversification at the intrafamilial level. Phylogenetic trees constructed with the variable nucleotide sites of the chloroplast genes place maize basal to the rice-wheat clade, revealing a close relationship between the Bambusoideae and Pooideae.

    Society for Molecular Biology and Evolution, 2002年12月01日, Molecular Biology and Evolution, 19 (12), 2084 - 2091, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Y. Vigouroux, M. McMullen, C. T. Hittinger, K. Houchins, L. Schulz, S. Kresovich, Y. Matsuoka, J. Doebley

    Crop species experienced strong selective pressure directed at genes controlling traits of agronomic importance during their domestication and subsequent episodes of selective breeding. Consequently, these genes are expected to exhibit the signature of selection. We screened 501 maize genes for the signature of selection using microsatellites or simple sequence repeats (SSRs). We applied the Ewens-Watterson test, which can reveal deviations from a neutral-equilibrium model, as well as two nonequilibrium tests that incorporate the domestication bottleneck. We investigated two classes of SSRs: those known to be polymorphic in maize (Class I) and those previously classified as monomorphic in maize (Class II). Fifteen SSRs exhibited some evidence for selection in maize and 10 showed evidence under stringent criteria. The genes containing nonneutral SSRs are candidates for agronomically important genes. Because demographic factors can bias our tests, further independent tests of these candidates are necessary. We applied such an additional test to one candidate, which encodes a MADS box transcriptional regulator, and confirmed that this gene experienced a selective sweep during maize domestication. Genomic scans for the signature of selection offer a means of identifying new genes of agronomic importance even when gene function and the phenotype of interest are unknown.

    2002年07月23日, Proceedings of the National Academy of Sciences of the United States of America, 99 (15), 9650 - 9655, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Yoshihiro Matsuoka, Yves Vigouroux, Major M. Goodman, Jesus G. Sanchez, Edward Buckler, John Doebley

    There exists extraordinary morphological and genetic diversity among the maize landraces that have been developed by pre-Columbian cultivators. To explain this high level of diversity in maize, several authors have proposed that maize landraces were the products of multiple independent domestications from their wild relative (teosinte). We present phylogenetic analyses based on 264 individual plants, each genotyped at 99 microsatellites, that challenge the multiple-origins hypothesis. Instead, our results indicate that all maize arose from a single domestication in southern Mexico about 9,000 years ago. Our analyses also indicate that the oldest surviving maize types are those of the Mexican highlands with maize spreading from this region over the Americas along two major paths. Our phylogenetic work is consistent with a model based on the archaeological record suggesting that maize diversified in the highlands of Mexico before spreading to the lowlands. We also found only modest evidence for postdomestication gene flow from teosinte into maize.

    2002年04月30日, Proceedings of the National Academy of Sciences of the United States of America, 99 (9), 6080 - 6084, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Y. Matsuoka, S. E. Mitchell, S. Kresovich, M. Goodman, J. Doebley

    To evaluate the performance of microsatellites or simple sequence repeats (SSRs) for evolutionary studies in Zea, 46 microsatellite loci originally derived from maize were applied to diverse arrays of populations that represent all the diploid species of Zea and 101 maize inbreds. Although null phenotypes and amplification of more than two alleles per plant were observed at modest rates, no practical obstacle was encountered for applying maize microsatellites to other Zea species. Sequencing of microsatellite alleles revealed complex patterns of mutation including frequent mdels m the regions flanking microsatellite repeats. In one case, all variation at a microsatellite locus came from indels in the flanking region rather than in the repeat motif. Maize microsatellites show great variability within populations and provide a reliable means to measure intraspecific variation. Phylogeographic relationships of Zea populations were successfully reconstructed with good resolution using a genetic distance based on the infinite allele model, indicating that microsatellite loci are useful in evolutionary studies in Zea. Microsatellite loci show a principal division between tropical and temperate inbred lines, and group inbreds within these two broad germplasm groups in a manner that is largely consistent with their known pedigrees.

    2002年, Theoretical and Applied Genetics, 104 (2-3), 436 - 450, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Yves Vigouroux, Jennifer S. Jaqueth, Yoshihiro Matsuoka, Oscar S. Smith, William D. Beavis, J. Stephen C. Smith, John Doebley

    Microsatellites are important tools for plant breeding, genetics, and evolution, but few studies have analyzed their mutation pattern in plants. In this study, we estimated the mutation rate for 142 microsatellite loci in maize (Zea mays subsp, mays) in two different experiments of mutation accumulation. The mutation rate per generation was estimated to be 7.7 x 10-4 for microsatellites with dinucleotide repeat motifs, with a 95% confidence interval from 5.2 x 10-4 to 1.1 x 10-3. For microsatellites with repeat motifs of more than 2 bp in length, no mutations were detected so we could only estimate the upper 95% confidence limit of 5.1 x 10-5 for the mutation rate. For dinucleotide repeat microsatellites, we also determined that the variance of change in the number of repeats (σm 2) is 3.2. We sequenced 55 of the 73 observed mutations, and all mutations proved to be changes in the number of repeats in the microsatellite or in mononucleotide tracts flanking the microsatellite. There is a higher probability to mutate to an allele of larger size. There is heterogeneity in the mutation rate among dinucleotide microsatellites and a positive correlation between the number of repeats in the progenitor allele and the mutation rate. The micro-satellite-based estimate of the effective population size of maize is more than an order of magnitude less than previously reported values based on nucleotide sequence variation.

    Society for Molecular Biology and Evolution, 2002年, Molecular Biology and Evolution, 19 (8), 1251 - 1260, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Y. Yasui, S. Nasuda, Y. Matsuoka, T. Kawahara

    A novel plant short interspersed nuclear element (SINE) was identified in the second intron of the acetyl CoA carboxylase gene of Aegilops umbellulata which has been designated "Au", for the host species in which it was discovered. Au elements have a tRNA-related region, direct flanking repeats, and a short stretch of T at the 3′ end, which are features common to Au and previously characterized SINEs. Au elements are detected in the genomes of several monocots and dicots by DNA dot hybridization and are also found in the tobacco genome by database searching. Au elements are present at an especially high copy number (approximately 104 copies per haploid genome) in wheat and Ae. umbellulata. This suggests a recent amplification of Au in the Triticum and Aegilops species. In situ hybridization revealed a dispersed distribution of Au elements on wheat chromosomes. Au elements were amplified by PCR from monocot and dicot species and the phylogenetic relationships among Au elements were inferred. This phylogenetic analysis suggests amplification of Au elements in a manner consistent with the retrotransposon model for SINE dispersion. The high copy number of Au elements and their dispersed distribution in wheat are desirable characteristics for a molecular marker system in this important species.

    2001年, Theoretical and Applied Genetics, 102 (4), 463 - 470, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Molecular analysis of a 21.1-kb fragment of wheat chloroplast DNA bearing RNA polymerase subunit (rpo) genes

    Y. Ohnishi, H. Tajiri, Y. Matsuoka, K. Tsunewaki

    The entire nucleotide sequence of a 21.1-kb fragment of wheat chloroplast (ct) DNA was determined. This fragment carries 18 intact genes and parts of two additional genes, including the three RNA polymerase genes rpoB, rpoC1, and rpoC2. The gene arrangement of this region is conserved in wheat, rice, and maize, but not in non-grass species. Comparison of these 20 genes in wheat, rice, and maize showed that tRNA genes evolved more slowly than protein-coding genes in the chloroplast genome. Intergenic regions evolved much faster than both types of genes. Although the 19 genes of wheat, except for orf42, showed high identity to those of other plants, there were three novel structural features in the wheat rpoC2 gene a deletion of 81 bp in the middle region, a variable insertion (408 bp), and a nonsense mutation in the 3' terminal region, resulting in truncation of a sequence of ca. 10 amino acids. An intermolecular recombination between the stretches of CTTAT and CTTTT was suggested as the mechanism of the 81-bp deletion in the wheat rpoC2 gene. Evolutionary distance between the chloroplast genomes of wheat and maize was larger than those between wheat and rice and between rice and maize.

    1999年, Genome, 42 (6), 1042 - 1049, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Yoshihiro Matsuoka, Koichiro Tsunewaki

    The evolutionary dynamics of Ty1-copia group retrotransposons in grass were examined by reverse transcriptase (RT) domain analysis. Twenty-three rice RT sequences were newly determined for this report. Phylogenetic analysis of 177 RT sequences, mostly derived from wheat, rice, and, maize, showed four distinct families, which were designated G1, G2, G3, and G4. Three of these families have elements obtained from distantly related species, indicative of origins prior to the radiation of grass species. Results of Southern hybridization and detailed comparisons between the wheat and rice sequences indicated that each of the families had undergone a distinct pattern of evolution. Multiple families appear to have evolved in parallel in a host species. Analyses of synonymous and nonsynonymous substitutions suggested that there is a low percentage of elements carrying functional RT domains in the G4 family, indicating that the production of new G4 elements has been controlled by a small number of elements carrying functional RT domains.

    Society for Molecular Biology and Evolution, 1999年, Molecular Biology and Evolution, 16 (2), 208 - 217, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Yoshihiro Matsuoka, Koichiro Tsunewaki

    Distribution of wheat retrotransposon families (families 1 to 7) was examined in 11 Gramineae species by the use of representative reverse transcriptase domain clones selected from six of the seven wheat retrotransposon families previously identified as probes. The homologues of families 3, 4, 5, and 7 retrotransposons were detectable only in the Pooideae species, suggesting that the distribution of the retrotransposons related to these families is restricted to the Pooideae subfamily. The representatives of families I and 2, distantly related to families 3 to 7, revealed homologues additionally in the species outside the Pooideae subfamily including rice. These results suggest that the retrotransposons related to the former families have wider distribution than those related to families 3, 4, 5, and 7. Analysis of a wheat genomic clone confirmed that the family i representative reverse transcriptase domain clone is a Ty1-copia group retrotransposon derivative, which we have named Tar1. On the basis of these results, the origin of wheat retrotransposon families is discussed.

    1997年12月, Genes and Genetic Systems, 72 (6), 335 - 343, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Yoshihiro Matsuoka, Koichiro Tsunewaki

    Restriction fragment length polymorphism (RFLP) in the reverse transcriptase domain of family I retrotransposons was investigated in the genera Triticum and Aegilops. On the basis of the TaqI restriction site distribution within or near the reverse transcriptase domain, we defined the four types (I-IV) of the family 1 wheat retrotransposons. The type I elements are assumed to have been present much before the differentiation of the genera because they distribute in rye and barley. On the other hand, the type II-IV elements appeared to have occurred during speciation of Triticum and Aegilops species and were transmitted vertically from species of lower ploidy to those of higher ploidy, because they distribute in most of the polyploid species whereas they are detectable only in six of 15 diploid species. These findings suggest a possibility that the genomes carrying the new family 1 retrotransposons have been preferred in successful establishment of polyploid species.

    1997年12月, Genes and Genetic Systems, 72 (6), 345 - 351, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Ohnishi Ohmi, Matsuoka Yoshihiro

    Four newly discovered and seven previously known Fagopyrum species were classified based on their morphology, isozyme variability, and RFLP of chloroplast DNA (cpDNA). Three independently constructed phylogenetic trees showed good agreement and we had sufficient confidence in them to assert that they probably reflect the phylogenetic relationships among the Fagopyrum species. The new classification differs from Steward (1930)'s classification in the position of Fagopyrum tataricum and F. gracilipes; F. tataricum is very close to F. cymosum. The new classification resolved several problems which we suffered from, when we used Steward's classifiction. Three new species, F. pleioramosum, F. callianthum and F. capillatum are closely related to F. gracilipes. New species F. homotropicum is very close to F. esculentum in morphology as well as in isozyme variability.

    The Genetics Society of Japan, 1996年12月01日, Genes & genetic systems, 71 (6), 383 - 390, 英語

  • Koichiro Tsunewaki, Gui-Zhi Wang, Yoshihiro Matsuoka

    Plasmons (= cytoplasms) of eight Triticum species (ten accessions) and 24 Aegilops species (36 accessions) have been introduced by repeated backcrosses to 12 genotypes of hexaploid, common wheat. At transfer problems such as crossing barrier, preferential transmission of a gametocidal or parthenogenesis-inducing chromosome, and mistagging of the material occurred, all of which hindered the plasmon transfer program. Of the 552 genotype- plasmon combinations produced, 532 (96.4%) had reached the B10 or a later backcross generation, 15 (2.7%) the B7-B9, generation, and the remaining 5 (0.9%) the B4-B6 generation by summer, 1996. Pollen and selfed seed fertilities were observed in plants of all the field-grown lines in the 1992- 1993 winter crop season, and backcrossed and selfed seed fertilities of plants grown in a greenhouse under a long day condition (17-h light) were assessed in the five latest backcross generations. Selfed seed fertility was found to be a better parameter of male fertility than was pollen fertility. Female fertility, as estimated from the backcrossed seed fertility, was about three times more tolerant to genetic stress caused by the alien plasmon transfer than was male fertility evaluated from both the pollen and selfed seed fertilities. The plasmons studied could be classified into 14 fertility spectrum groups. Most, excluding 15 plasmons belonging to the B, D, D2, S, and Sb plasmon types, were considered the male sterile plasmon to common wheat.

    1996年, Genes and Genetic Systems, 71 (5), 293 - 311, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Yoshihiro Matsuoka, Koichiro Tsunewaki

    Variations in the reverse transcriptase domain were analyzed to clarify the family structure of retrotransposons in the wheat genome. Seven families were identified on the basis of the nucleotide sequence similarities of the domain. These families are common to the genomes of ancestral diploid species of wheat, evidence that they were established prior to diploid speciation, and their presence in barley and rice was suggested. Recent activity of some of the families was inferred in wheat on the basis of data that included synonymous and nonsynonymous nucleotide substitution rates in the reverse transcriptase domain.

    Oxford University Press, 1996年, Molecular Biology and Evolution, 13 (10), 1384 - 1392, 英語

    [査読有り]

    研究論文(学術雑誌)

MISC

  • パンコムギの起原地はどこか?

    松岡由浩, 丹野研一, 佐久間俊

    2022年02月, 考古学ジャーナル, 765, 29 - 31

    記事・総説・解説・論説等(学術雑誌)

  • パンコムギと野生種タルホコムギ交雑由来の新奇8倍性合成コムギの創生

    GAO Y., 松岡由浩, 辻本壽, 辻本壽, 岸井正浩, 佐久間俊, 石井孝佳, 石井孝佳

    2022年, 育種学研究, 24

  • 祖先野生種プレブリーディングによるコムギ遺伝資源の創出と育種展開

    松岡由浩, 石井孝佳, 宅見薫雄, 辻本壽, 岸井正浩

    2020年, アグリバイオ, 4 (3)

  • コムギ葉緑体DNAの全塩基配列の決定 IV. 葉緑体ゲノムでみられたMITE様配列について

    荻原 保成, 磯野 一宏, 小島 俊雄, 遠藤 亮, 村井 里佳, 村井 耕二, 華岡 光正, 椎名 隆, 寺地 徹, 宇都木 繁子, 村田 稔, 森 直樹, 宅見 薫雄, 池尾 一穂, 五条堀 孝, 松岡 由浩, 大西 由佳里, 田尻 晃, 常脇 恒一郎

    2000年04月, 育種学研究 = Breeding research, 2 (1), 30, 日本語

共同研究・競争的資金等の研究課題

  • 野生コムギの生存戦略としての特異的休眠機構の解明と遺伝資源保全への応用

    森 直樹, 松岡 由浩

    日本学術振興会, 科学研究費助成事業, 基盤研究 (B) 一般, 神戸大学大学院農学研究科, 2023年04月 - 2028年03月

  • 重要遺伝資源タルホコムギにおける生殖関連遺伝子の同定とその育種利用

    角井 宏行, 松岡 由浩, 岡田 萌子

    日本学術振興会, 科学研究費助成事業, 基盤研究(B), 京都大学, 2022年04月01日 - 2027年03月31日

  • 日本のコムギ研究リソースと国際農業研究機関の連結による新遺伝資源創出と育種展開

    松岡 由浩, 石井 孝佳, 宅見 薫雄, 辻本 壽

    日本学術振興会, 科学研究費助成事業 国際共同研究加速基金(国際共同研究強化(B)), 国際共同研究加速基金(国際共同研究強化(B)), 福井県立大学, 2019年10月07日 - 2025年03月31日

    温暖化で深刻な負の影響を受けるパンコムギでは、育種を加速して、気候変動に打ち克つ品種を開発する必要がある。本研究は、6倍性パンコムギ(AABBDDゲノム)に祖先野生種タルホコムギ(DD)のコアコレクションを交配・胚培養して、多数の「8倍性合成コムギ(AABBDDDD)」を作出する。過去100年、コムギ染色体数の発見、倍数性進化の解明等、日本は世界の研究をリードしており、最高水準の研究リソース(人材、技術、遺伝資源)を有する。本研究は、ゲノム解読が完了した好機に、研究リソースを結集し、気候変動下の食糧生産問題の解決に向けて、20世紀に「緑の革命」を主導したことで著名な国際トウモロコシ・コムギ改良センター(CIMMYT、メキシコ)との共同研究を推進することを目的とする。 本研究では、研究期間内に2つの研究計画(① 8倍性合成コムギの作出、② 8倍性合成コムギ派生系統を用いたDゲノム改良と遺伝様式の解明)を実施する。本年度のそれぞれの研究実績は次の通りである。 ①8倍性合成コムギの作出:合計47系統のタルホコムギについて、パンコムギのエリート品種(農林61号もしくはBORLAUG 100)と交配し、胚培養することにより作出したF1雑種をコルヒチン処理し、8倍体雑種を作出した。また、一部の8倍体系統については、パンコムギとの戻し交雑により7倍体を作出した。 ②8倍性合成コムギ派生系統を用いたDゲノム改良と遺伝様式の解明:パンコムギのDゲノム特異的なFISH用オリゴDNAプローブを2種類デザインする事に成功し、1種類を合成した。また、本研究計画と関連して申請し受理された「先進ゲノム支援」の支援により、タルホコムギ1系統について新規ゲノム配列を取得した。さらに、別のタルホコムギ1系統について、葉、根、幼穂などからトータルRNAを抽出し、混合したRNAのIso-Seqリードを取得した。

  • アポミクシス形質を獲得してクローン胚を形成するコムギの作出と関連遺伝子の同定

    松岡 由浩, 宅野 将平

    日本学術振興会, 科学研究費助成事業 基盤研究(B), 基盤研究(B), 福井県立大学, 2019年04月01日 - 2024年03月31日

    食糧生産を巡る状況が厳しさを増す今日、「いかにしてヘテロシス(雑種強勢)が分離しない永久ハイブリッド品種を作るか」は育種科学の核心的課題である。アポミクシス(無融合種子形成)は、クローン種子を形成することにより、ヘテロシスを固定する。しかし、パンコムギでは、アポミクシスは知られていない。本研究では、コムギ系統を交配し、アポミクシス形質を獲得してクローン胚を形成するコムギを作出することを目的とする。さらに、ゲノム・トランスクリプトーム解析により、アポミクシス形質発現に関わるコムギ遺伝子を同定することを目指す。上記の目的を達成するために実施した実験等により今年度は次の成果を得た。 ・アポミクシスは、雌性の非還元配偶子(減数分裂の回避により生じる配偶子。体細胞と同じ数の染色体をもつ)が単為生殖して発現する。今年度は、非還元配偶子を形成するコムギ系統LDNと単為生殖するコムギ系統 (Var)-Salmonを交配して雑種(F1)に、LDNを交配して得た(Var)-Salmon-LDN_F1BC1、にLDNを1回戻し交配し、(Var)-Salmon-LDN_F1BC2を得た。 ・アポミクシス形質発現に関わる遺伝子アリルをもつタルホコムギ系統のゲノム配列を新規に取得するため、高分子DNAを抽出し、次世代シークエンサー解析(ロングリード)により、追加のゲノムデータを取得した。そして、このタルホコムギの新規ゲノム配列を構築するための解析を進めた。 ・単為生殖するコムギ系統(Kot)-Salmonの幼穂由来からRNAを用いてRNA-seq解析を行った。また、このコムギ系統に特異的に発現する遺伝子を探索するための解析を開始した。

  • パンコムギの起原地はどこか?:植物遺伝学と考古植物学の協働による学際的研究

    松岡 由浩

    日本学術振興会, 科学研究費助成事業 挑戦的研究(萌芽), 挑戦的研究(萌芽), 福井県立大学, 2020年07月30日 - 2023年03月31日

    西アジアで誕生し、ユーラシア大陸全体に広がり、各地で文明を支えたパンコムギは、トルコ南東部を中心とする「肥沃な三日月地帯」で栽培化され「作物」となった二粒系コムギが、その畑の周囲に雑草として生えていたタルホコムギ(野生種)と自然交雑して誕生した。現在、パンコムギの正確な起原地は未だ不明であり、このことが、初期コムギ農耕の全体像を理解する上で重大な障害となっている。本研究は、ゲノム配列情報を用いた遺伝子比較解析を世界に先駆けてパンコムギの起原地研究に適用して植物遺伝学と考古植物学の成果を統合的に考察することで、初期コムギ農耕の成立と発展に関わる重要問題の解決に挑戦することを目的とする。 本年度は、タルホコムギ種内に存在する3つのlineage(共通祖先から派生した系統群)のそれぞれから選ばれた代表系統(合計3系統)のうち、2系統について、次世代シークエンサーによるゲノム解析(ロングリード解析)を行い、データを取得した。また、このデータと、染色体立体配座捕捉法によるゲノム解析データ(昨年度取得)を合わせて、デノボ・アッセンブルによる新規ゲノム配列を取得するための解析を開始した。また、上記代表系統(合計3系統)のうち、1系統について、ロングリードRNAseq解析を行い、新規ゲノム配列に遺伝子情報(アノテーション)をつけるための準備を完了した。そして、植物遺伝学と考古植物学の成果を統合的に考察してパンコムギの起原を明らかとする研究アプローチについての論考を発表した(松岡、丹野、佐久間 2021)。

  • 高温耐性育種のためのコムギ野生植物変異の開拓

    辻本 壽, 松岡 由浩, エリタエブ アミン, 岡本 昌憲, タヘル イザット, ヤシル ゴラフィ, エルバシル アワド

    日本学術振興会, 科学研究費助成事業 基盤研究(B), 基盤研究(B), 鳥取大学, 2015年04月01日 - 2018年03月31日

    申請者は、実用コムギ品種の遺伝的背景に、近縁野生植物タルホコムギの種内変異を包含させた「多重合成コムギ(MSD)集団」を育成した。これを、スーダン農業研究機構の高温ストレス圃場で栽培し、現地の育種家とともに、生育のよい系統を選抜した。これらは、人工気象機内の高温条件でも旺盛な生育をすることを確認した。一方で、MSD集団から400個体を任意に選び、スーダン農業研究機構の3カ所の圃場にて栽培し、農業形質を測定した。また、これら系統を大量のマーカーによりジェノタイピングした。本研究で構築した高温耐性コムギ育種プラットフォームは、今後の高温耐性のマーカー選抜育種および高温耐性機構の解明に有用である。

  • コムギ倍数化:2n配偶子の合体によるF1雑種ゲノム倍加の遺伝機構の解明

    松岡 由浩

    日本学術振興会, 科学研究費助成事業 基盤研究(B), 基盤研究(B), 福井県立大学, 2015年04月01日 - 2018年03月31日

    植物の倍数種形成を導く「F1雑種ゲノム倍加」の遺伝機構を明らかとするため、パンコムギ(Triticum aestivum L. subsp. aestivum)の祖先種を人工的に交配して作出した3倍体F1雑種を材料として量的形質遺伝子座(QTL)解析を行い、11個のQTLを見出した。また、花粉母細胞の比較観察結果から、これらのQTLは、F1雑種の2n配偶子形成に関係するものを含むと考えられた。

  • ユーラシア広域分布種のコアコレクションを使った適応遺伝子の解析と保全への応用

    河原 太八, 松岡 由浩, 最相 大輔, 笹沼 恒男, 宅見 薫雄, 山根 京子

    日本学術振興会, 科学研究費助成事業 基盤研究(B), 基盤研究(B), 京都大学, 2010年 - 2012年

    タルホコムギの分布全域についてその遺伝的変異を研究したところ,葉緑体ゲノムでは1つのクラスターであったが,核ゲノムでは互いに離れた2つのリネージの存在が見いだされ,この2つは数百万年にわたる隔離で成立したと推定された。なお,現在では2つが同所的に生育している場合もあり,それぞれの分集団が成立した後,分布を広げたと考えられる。近縁の野生オオムギでも同様な分集団構造が見られたので,こうした広域分布種では,種の進化過程で生じる分集団構造が重要であることが明らかとなった。

  • イネ科植物における倍数種形成の初期過程:進化の再現系を用いた遺伝基盤の解明

    松岡 由浩

    日本学術振興会, 科学研究費助成事業 若手研究(B), 若手研究(B), 福井県立大学, 2009年 - 2011年

    イネ科植物における倍数種形成メカニズムを明らかにすることを目指し、倍数化を導く配偶子形成に関わる遺伝子の解析に用いるコムギ実験系統を作出した。また、コムギ種問3倍体雑種にみられる、倍数種形成に「つながる」配偶子形成と「つながらない」配偶子形成を比較観察したところ、後者では、減数分裂の初期段階での重大な障害が生じ、これが主な原因となって稔性のある配偶子が形成されず、不稔となる可能性が示唆された。

  • 倍数化を導く減数分裂:非還元性配偶子形成の遺伝機構の解明

    松岡 由浩

    日本学術振興会, 科学研究費助成事業 若手研究(A), 若手研究(A), 福井県立大学, 2006年 - 2008年

    本研究では、種間交雑-倍数化による新しい種の形成プロセスにおいて重要な役割を果たす、非還元配偶子形成の遺伝的メカニズムの解明を目指し、種間雑種の自殖種子稔性に関する遺伝分析を行なった。二倍体コムギと四倍体コムギの交雑に由来する3倍体植物を材料として、マイクロサテライト・マーカーを用いて連鎖解析を行なった結果、二倍体コムギゲノム上に、種間雑種の自殖種子稔性の高低に影響する遺伝子座が存在することが示された。

  • コムギ近縁野生種を用いたユーラシア広域分布種の遺伝的多様性解析

    河原 太八, 安井 康夫, 宅見 薫雄, 松岡 由浩, 森 直樹, 山根 京子, 笹沼 恒男

    日本学術振興会, 科学研究費助成事業 基盤研究(A), 基盤研究(A), 京都大学, 2005年 - 2008年

    トルコから中国西部にかけて, ユーラシア大陸内陸部に広域く分布するタルホコムギ(Aegilops tauschii)について, 種内の葉緑体塩基配列・穂の形態・開花までの日数などについて変異を明らかにした。解析の結果同じような気候条件に対し, 分布の東と西で違う遺伝子の変異によって適応していることが分かったので, これらの遺伝子について塩基配列を決定しその変異を明らかにした。また乾燥に応答する遺伝子など, そのほかいくつかの遺伝子の変異を明らかにした。

  • ムギ農耕とそれを取り巻く生態系における環境・人・作物・雑草の相互関係に関する研究

    大田 正次, 冨永 達, 本江 昭夫, 森 直樹, 松岡 由浩, 大迫 敬義

    日本学術振興会, 科学研究費助成事業 基盤研究(A), 基盤研究(A), 福井県立大学, 2003年 - 2006年

    1.現地調査と採集品の概要:(1)トルコ南部をチュクロバ大学と共同で現地調査し,コムギ連,ドクムギ属など1709サンプルを収集.10月と12月にエギロプス属の自生集団において発芽調査.(2)イラン国立植物ジーンバンク(NPGBI)と合意書を交わしイラン北部と北西部を共同で現地調査し,コムギ連,ドクムギ属,ウマゴヤシ属など1557サンプルを収集.ライムギ属とドクムギ属の一部はMTAに基き種子の分譲を受けた.(3)ギリシア北部で現地調査を行い,ドクムギ属,アブラナ科など54サンプルを収集.2.コムギ近縁野生種の生態型分化:(1)Aegilops neglecta 2変種とAe.columnarisがトルコ南部において生態的に異なる生育地に分布すること,contorta変種が記載のなかったトルコ南西部にも分布し人間の活動とともに分布を広げつつあること,を明らかにした.遺伝的類縁性解明のため交配実験と葉緑体DNAの解析を実施中.(2)タルホコムギstrangulata亜種とmeyeri変種がそれぞれカスピ海南岸の石灰岩および砂質土壌に適応した生態型であることを明らかにした.(3)エギロプス属では1穂に休眠性の異なる二型の種子を着け,撹乱した生育地での迅速な初期生育と危険回避を実現していることを明らかにした.3.ムギ作随伴雑草の随伴様式と遺伝的多様性:(1)イラン北西部の路傍にLolium temulentumとL.persicumが同所的に生育していることを明らかにした.収集品の一部を遺伝学的分析のため栽培中.(2)イランでは小穂脱落性の雑草ライムギがムギ畑に普通に見られ,とくに栽培ライムギの多様性中心に高頻度で見られた.イランの栽培・雑草ライムギ5集団に標準型B染色体が見られた.野生および栽培ライムギ間の浸透交雑が明らかとなった.4.普通系コムギの成立:イラン北部アルボルツ山麓で栽培される二粒系コムギ畑の周縁部にタルホコムギが混入するのが明らかとなった.5.研究者交流:2005年4-5月と2006年9月にチュクロバ大学から大学院生と助教授をそれぞれ招聘した.

  • 種間雑種において発現するトランスポゾン群の解析

    松岡 由浩

    日本学術振興会, 科学研究費助成事業 若手研究(B), 若手研究(B), 福井県立大学, 2002年 - 2004年

    本研究は、植物の雑種ゲノムの安定化におけるトランスポゾンの役割を解明することを目的とし、コムギ植物を材料に、雑種ゲノムにおいて発現するトランスポゾン群の体系的な解析を行った。 本研究の主な成果は以下の通り。 (1)マカロニコムギ-タルホコムギ三倍体種間雑種における高頻度染色体倍加:マカロニコムギ(Triticum durum、2n=28、♀親)とタルホコムギ(Aegilops squarrosa、2n=14、♂親)の交配に由来する三倍体F_1雑種(2n=21)は、高い花粉稔性及び、自殖種子着粒率を示すことを見出した。さらに、細胞遺伝学的解析により、(a)この三倍体F_1雑種では、減数分裂の過程で非還元配偶子が高頻度に形成され、(b)雌雄の非還元性配偶子の合体により六倍体F_2雑種(2n=2)が生じることが明らかとなった。六倍体F_2雑種は、正常に成長し、高頻度(>90%)で種子をつける。従来、ペルシアコムギ(Triticum carthlicum)とタルホコムギの三倍体F_1雑種で、高頻度染色体倍加が起きることは知られていたが、マカロニコムギ-タルホコムギ三倍体雑種での高頻度染色体倍加は知られておらず、この発見は新規でる。この結果は、現在広く栽培されるパンコムギ(六倍体、2n=42)の母方の祖先がマカロニコムギである可能性を示唆する。 (2)コムギ種間雑種におけるトランスポゾンの発現:マカロニコムギ-タルホコムギ三倍体F_1雑種とその自殖後代(F_2-F_3)の根、葉と幼穂からtotalRNAを抽出し、RT-PCR法により、copia型レトロトランスポゾンの発現の有無を調査したが、明確なトランスポゾン転写活性は、検出されなかった。

  • 遺伝子シャトリング法による硬質マカロニコムギの育成

    常脇 恒一郎, 村井 達夫, 池口 正二郎, 松岡 由浩

    日本学術振興会, 科学研究費助成事業 基盤研究(A), 基盤研究(A), 福井県立大学, 1995年 - 1997年

    本研究では、染色体光学的手法を用いて次の3つのマカロニコムギ系統を育成することを目標に研究を実施した。 (1)高製パン性マカロニコムギ系統の育成:Langdonの1D(1A)及び1D(1B)置換系統に高品質パンコムギのGlu-D1d遺伝子を導入するための研究を実施した。これには、StoaとMaxという2パンコムギ品種をLangdonの1D(1A)及び1D(1B)置換系統に交配し、F_2世代において染色体数を決定し,2n=28または29の個体を選抜した。これら個体の自殖次代の種子のグルテニン分画の分析を行い、Glu-D1dホモの個体ないし系統の選抜に成功した。これら系統の種子を増殖し、その製パン性をLangdonと比較したところ、タンパク質含量については差異が認められなかったが、ミキシング耐性が向上し、パンの体積と外見がともに明瞭に改善された。 (2)半矮性マカロニコムギ系統の育成:パンコムギ品種、農林10号の2半矮性遺伝子、Rht1とRht2をLangdonに導入し、その半矮性系統の育成を試みた。まず、農林10号とLangdonのF_2世代において染色体数に関する選抜を、F_3世代においては草丈と播性について調査を行った。その結果、マカロニコムギと同一染色体構成をもち、4A染色体上に半矮性遺伝子Rht1を、5A染色体上に秋播性遺伝子vrn1をもつ固定系統を得た。次に、4D染色体上のRht2をマカロニコムギに導入するため、農林10号をLngdonの4D(4A)および4D(4B)置換系統に交配し、F_2世代において染色体数と草丈について選抜した。その結果、2n=29及び31の個体の中に半矮性のものが得られた。 (3)秋播性マカロニコムギ系統の育成:上記(2)の研究において、幸にも5A染色体上のvrn1について固定した秋播性系統が育成できた。そこで、もう一方の秋播性遺伝子,vrn3(5D染色体上)をマカロニコムギに導入するため、Langdonの5D(5B)置換系統に北海道の2秋播性パンコムギ、タクネコムギ及びホロシリコムギを交配し、そのF_2世代において染色体数と播性について選抜した。その結果、2n=28または30の植物の後代で秋播性の高い7個体得た。