研究者紹介システム
| 足助 聡一郎 |  |
| アスケ ソウイチロウ | |
| 大学院農学研究科 生命機能科学専攻 | |
| 助教 | |
| 農学関係 |
研究活動
研究キーワード
研究分野
受賞
論文
Since emerging in Brazil in 1985, wheat blast has spread throughout South America and recently appeared in Bangladesh and Zambia. Here we show that two wheat resistance genes, Rwt3 and Rwt4, acting as host-specificity barriers against non-Triticum blast pathotypes encode a nucleotide-binding leucine-rich repeat immune receptor and a tandem kinase, respectively. Molecular isolation of these genes will enable study of the molecular interaction between pathogen effector and host resistance genes.
2023年02月16日, Nature plants, 英語, 国際誌[査読有り]
研究論文（学術雑誌）
- Wiley, 2022年08月11日, Molecular Plant Pathology, 23 (11), 1658 - 1670, 英語
[査読有り]
研究論文（学術雑誌）
MAIN CONCLUSION: MLP-PG1, identified in Cucurbita pepo, plays a crucial role in resistance against fungal pathogens through the induction of pathogenesis-related genes. ASTRACT: MLP-PG1, a major latex-like protein (MLP) from zucchini (Cucurbita pepo), was identified as a transporting factor for hydrophobic organic pollutants. MLPs are members of the Bet v 1 family, similar to pathogenesis-related class 10 proteins (PR-10s). However, the biological functions of MLPs remain unclear. Herein, we show that MLP-PG1 induces the expression of pathogenesis-related (PR) genes and indirectly promotes resistance against pathogens. The activity of the MLP-PG1 promoter in leaves of transgenic tobacco plants was significantly enhanced by inoculation with Pseudomonas syringae pv. tabaci. However, MLP-PG1 did not induce direct resistance through RNase activity. Therefore, we examined the possibility that MLP-PG1 is indirectly involved in resistance; indeed, we found that MLP-PG1 induced the expression of defense-related genes. Overexpression of MLP-PG1 highly upregulated PR-2 and PR-5 and decreased the area of lesions caused by Botrytis cinerea in the leaves of transgenic tobacco plants. Our results demonstrate that MLP-PG1 is involved in indirect resistance against plant diseases, especially caused by fungal pathogens, through the induction of PR genes. This study is the first report to show the induction of PR genes by the expression of MLP from the RNA sequencing analysis and the involvement of MLP-PG1 in the resistance.
2021年11月30日, Planta, 255 (1), 10 - 10, 英語, 国際誌[査読有り]
研究論文（学術雑誌）
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 A. 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. A. 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11月14日, Phytopathology, 111 (11), PHYTO02210080R - 2029, 英語, 国際誌[査読有り]
研究論文（学術雑誌）
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.
Springer Science and Business Media LLC, 2021年07月, Journal of General Plant Pathology, 87 (4), 201 - 208, 英語[査読有り]
研究論文（学術雑誌）
The specificity between pathotypes of Pyricularia oryzae and genera of gramineous plants is governed by gene-for-gene interactions. Here, we show that avirulence genes involved in this host specificity have undergone different modes of functional losses dependent on or affected by genomic compartments harboring them. The avirulence of an Eleusine pathotype on wheat is controlled by five genes, including PWT3, which played a key role in the evolution of the Triticum pathotype (the wheat blast fungus). We cloned another gene using an association of its presence or absence with pathotypes and designated it as PWT6. PWT6 was widely distributed in a lineage composed of Eleusine and Eragrostis isolates but was completely absent in a lineage composed of Lolium and Triticum isolates. On the other hand, PWT3 homologs were present in all isolates, and their loss of function in Triticum isolates was caused by insertions of transposable elements or nucleotide substitutions. Analyses of whole-genome sequences of representative isolates revealed that these two genes were located in different genomic compartments; PWT6 was located in a repeat-rich region, while PWT3 was located in a repeat-poor region. These results suggest that the course of differentiation of the pathotypes in P. oryzae appears to be illustrated as processes of functional losses of avirulence genes but that modes of the losses are affected by genomic compartments in which they reside.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
2021年06月, Molecular plant-microbe interactions : MPMI, 34 (6), 680 - 690, 英語, 国際誌[査読有り]
研究論文（学術雑誌）
Wheat blast caused by the Triticum pathotype of Pyricularia oryzae is a serious threat to wheat production in South America and Asia. Rmg8 is a promising gene for resistance to the wheat blast fungus found in common wheat. To predict its durability, stability of its corresponding avirulence gene, AVR-Rmg8, was evaluated based on the genome structure around AVR-Rmg8 in an isolate from Triticum and on polymorphisms of AVR-Rmg8 in isolates from Lolium spp., which are closely related to Triticum isolates. AVR-Rmg8 was located in a gene-rich, repeat-poor region, suggesting that AVR-Rmg8 is not as easily lost as avirulence genes located in repeat-rich regions. This finding implies that Rmg8 is relatively durable compared with resistance genes corresponding to avirulence genes in repeat-rich regions. AVR-Rmg8 was widely distributed in Lolium isolates and comprised three types or variants, eL1, eL2, and eL3. Complementation tests revealed that eL1 and eL2 were functional and recognized by Rmg8. In eL3, however, retrotransposon Pyret was inserted into the ORF of AVR-Rmg8. Actually, three isolates carrying eL3 were virulent on common wheat cultivar S-615 carrying Rmg8, indicating that the insertion of Pyret caused a loss of function of AVR-Rmg8. Nevertheless, the three isolates have survived in nature, suggesting that AVR-Rmg8 is not indispensable for survival of Pyricularia isolates and, in turn, that Rmg8 is not likely to be completely durable.
SPRINGER JAPAN KK, 2021年01月, Journal of general plant pathology, 87 (1), 1 - 8, 英語[査読有り]
研究論文（学術雑誌）
Wheat blast caused by the Triticum pathotype of Pyricularia oryzae was first reported in 1985 in Brazil and recently spread to Bangladesh. We tested whether Rmg8 and RmgGR119, recently identified resistance genes, were effective against Bangladeshi isolates of the pathogen. Common wheat accessions carrying Rmg8 alone (IL191) or both Rmg8 and RmgGR119 (GR119) were inoculated with Brazilian isolates (Br48, Br5, and Br116.5) and Bangladeshi isolates (T-108 and T-109). Br48, T-108, and T-109 carried the eI type of AVR-Rmg8 (the avirulence gene corresponding to Rmg8) while Br5 and Br116.5 carried its variants, eII and eII' types, respectively. Detached primary leaves of IL191 and GR119 were resistant to all isolates at 25°C. At a higher temperature (28°C), their resistance was still effective against the eI carriers but was reduced to a low level against the eII/eII' carriers. A survey of databases and sequence analyses revealed that all Bangladeshi isolates carried the eI type which induced a higher level of resistance than the eII/eII' types. The resistance of IL191 (Rmg8/-) to the eI carriers was maintained even at the heading stage and at the higher temperature. In addition, GR119 (Rmg8/RmgGR119) displayed higher levels of resistance than IL191 at this stage. These results suggest that Rmg8 combined with RmgGR119 will be useful in breeding for resistance against wheat blast in Bangladesh.
2020年11月, Phytopathology, 110 (11), 1802 - 1807, 英語, 国際誌[査読有り]
研究論文（学術雑誌）
Eleusine isolates (members of the Eleusine pathotype) of Pyricularia oryzae are divided into two subgroups, EC-I and EC-II, differentiated by molecular markers. A multilocus phylogenetic analysis revealed that these subgroups are very close to Eragrostis isolates. EC-II and Eragrostis isolates were exclusively virulent on finger millet and weeping lovegrass, respectively, while EC-I isolates were virulent on both. The avirulence of EC-II on weeping lovegrass was conditioned by an avirulence gene, PWL1. All EC-II isolates shared a peculiar structure (P structure) that was considered to be produced by an insertion (or translocation) of a DNA fragment carrying PWL1. On the other hand, all EC-I and Eragrostis isolates were noncarriers of PWL1 and shared a gene structure that should have predated the insertion of the PWL1-containing fragment. These results, together with phylogenetic analyses using whole-genome sequences, suggest that the Eleusine-specific subgroup (EC-II) evolved through a loss of pathogenicity on weeping lovegrass caused by a gain of PWL1.
2020年02月, Molecular plant-microbe interactions : MPMI, 33 (2), 153 - 165, 英語, 国際誌[査読有り]
研究論文（学術雑誌）
Pyricularia oryzae is composed of pathotypes that show host specificity at the plant genus level. To elucidate the genetic mechanisms of the incompatibility between the Eleusine pathotype (pathogenic on finger millet) and common wheat, an Eleusine isolate (MZ5-1-6) was crossed with a Triticum isolate (Br48) pathogenic on wheat, and resulting F1 cultures were sprayed onto common wheat cultivars Hope, Norin 4 (N4), and Chinese Spring (CS). On Hope, avirulent and virulent cultures segregated in a 3:1 ratio, suggesting that two avirulence genes are involved. They were tentatively designated as eA1 and eA2. On N4 and CS, the segregation ratio was not significantly deviated from the 7:1, 15:1, or 31:1 ratios, suggesting that three or more genes are involved. A comparative analysis of the segregation patterns suggested that two of these genes were eA1 and eA2. A complementation test indicated that the third gene (tentatively designated as eA3) was the Ao9 type of the PWT3 gene controlling the avirulence of Avena and Lolium isolates on wheat. The fourth gene (tentatively designated as eA4) was detected by backcrossing 200R72, an F1 culture lacking eA1, eA2, and eA3, with Br48. Comparative analyses of phenotypes and the presence and/or absence of molecular markers in the F1 population revealed that some cultures were avirulent on N4/CS in spite of lacking eA1, eA2, eA3, and eA4, indicating the presence of the fifth gene (tentatively designated as eA5). Taken together, we conclude that at least five avirulence genes are involved in the incompatibility between MZ5-1-6 and N4/CS.
2020年02月, Phytopathology, 110 (2), 465 - 471, 英語, 国際誌[査読有り]
研究論文（学術雑誌）
The wheat blast fungus (Triticum pathotype of Pyricularia oryzae) first arose in Brazil in 1985 and has recently spread to Asia. Resistance genes against this new pathogen are very rare in common wheat populations. We screened 520 local landraces of common wheat collected worldwide with Br48, a Triticum isolate collected in Brazil, and found a highly resistant, unique accession, GR119. When F2 seedlings derived from a cross between GR119 and Chinese Spring (CS, susceptible control) were inoculated with Br48, resistant and susceptible seedlings segregated in a 15:1 ratio, suggesting that GR119 carries two resistance genes. When the F2 seedlings were inoculated with Br48ΔA8 carrying a disrupted allele of AVR-Rmg8 (an avirulence gene corresponding to a previously reported resistance gene, Rmg8), however, the segregation fitted a 3:1 ratio. These results suggest that one of the two genes in GR119 was Rmg8. The other, new gene was tentatively designated as RmgGR119. GR119 was highly resistant to all Triticum isolates tested. Spikes of GR119 were highly resistant to Br48, moderately resistant to Br48ΔA8 and a hybrid culture carrying avr-Rmg8 (nonfunctional allele), and highly resistant to its transformant carrying AVR-Rmg8. The strong resistance of GR119 was attributed to the combined effects of Rmg8 and RmgGR119.
2018年11月, Phytopathology, 108 (11), 1299 - 1306, 英語, 国際誌[査読有り]
研究論文（学術雑誌）
Rmg8 and Rmg7 are genes for resistance to the wheat blast fungus (Pyricularia oryzae), located on chromosome 2B in hexaploid wheat and chromosome 2A in tetraploid wheat, respectively. AVR-Rmg8, an avirulence gene corresponding to Rmg8, was isolated from a wheat blast isolate through a map-based strategy. The cloned fragment encoded a small protein containing a putative signal peptide. AVR-Rmg8 was recognized not only by Rmg8, but also by Rmg7, suggesting that these two resistance genes are equivalent to a single gene from the viewpoint of resistance breeding.
2018年05月, Molecular plant pathology, 19 (5), 1252 - 1256, 英語, 国際誌[査読有り]
研究論文（学術雑誌）
Wheat blast first emerged in Brazil in the mid-1980s and has recently caused heavy crop losses in Asia. Here we show how this devastating pathogen evolved in Brazil. Genetic analysis of host species determinants in the blast fungus resulted in the cloning of avirulence genes PWT3 and PWT4, whose gene products elicit defense in wheat cultivars containing the corresponding resistance genes Rwt3 and Rwt4 Studies on avirulence and resistance gene distributions, together with historical data on wheat cultivation in Brazil, suggest that wheat blast emerged due to widespread deployment of rwt3 wheat (susceptible to Lolium isolates), followed by the loss of function of PWT3 This implies that the rwt3 wheat served as a springboard for the host jump to common wheat.
2017年07月07日, Science (New York, N.Y.), 357 (6346), 80 - 83, 英語, 国際誌[査読有り]
研究論文（学術雑誌）
MISC
- 2022年, 樹木医学研究, 26 (2)国内2地域のアボカド(Persea americana)衰退木から検出されたキクイムシと菌類
速報，短報，研究ノート等（学術雑誌）
- 2022年, 日本森林学会大会学術講演集, 133rd国内植栽の熱帯果樹から検出された養菌性キクイムシと菌類
- 2022年, 樹木医学研究, 26 (3)南西諸島におけるデイゴ・マンゴー等の衰退枯死と養菌性キクイムシ随伴菌との関係
速報，短報，研究ノート等（学術雑誌）
- 2021年, 日本森林学会大会学術講演集, 132ndEuwallacea spp.が随伴するFusarium属菌のデイゴとマンゴーへの影響
- 2021年, 樹木医学研究, 25 (3)マンゴーの枯れ枝から検出されたEuwallacea属キクイムシに随伴するFusarium属菌の分類学的検討
速報，短報，研究ノート等（学術雑誌）
- 2020年, 日本農芸化学会大会講演要旨集(Web), 2020ズッキーニから同定された汚染物質輸送タンパク質のストレス応答への関与
- 2017年, 日本農芸化学会大会講演要旨集(Web), 2017ウリ科植物が持つ汚染物質輸送因子のストレス応答への関与
講演・口頭発表等
- Hands-on training on disease screening and surveillance of wheat blast (CIMMYT Bangladesh), 2023年03月02日, 英語Identification of genes for resistance to the wheat blast fungus
[招待有り]
公開講演，セミナー，チュートリアル，講習，講義等
- 日本育種学会第142回講演会, 2022年09月23日日本コムギ系統の圃場におけるコムギいもち病抵抗性の評価
- 日本植物病理学会令和４年度関西部会, 2022年09月21日コムギ近縁野生種におけるいもち病抵抗性遺伝子のスクリーニング
口頭発表（一般）
- 日本植物病理学会令和４年度関西部会, 2022年09月21日Identification of RmgSt19(t), a new gene for resistance to wheat blast with exceptional high-temperature insensitivity, in a tetraploid wheat accession
- 日本植物病理学会令和４年度関西部会, 2022年09月21日シコクビエいもち病菌と普通系コムギの非親和性を決定する PWT8 – Rwt8遺伝子相互作用の解析
口頭発表（一般）
- 12th Japan-US Seminar in Plant Pathology, 2022年08月31日Molecular basis of the resistance in wheat and barley against the blast fungus
[招待有り]
口頭発表（招待・特別）
- 12th Japan-US Seminar in Plant Pathology, 2022年08月29日Detection of resistance genes to wheat blast in oat, using a disruptant of PAT1 controlling the avirulence of the wheat blast fungus on oat.
ポスター発表
- 12th Japan-US Seminar in Plant Pathology, 2022年08月29日Cloning of PWT8, an avirulence gene of an Eleusine isolate of Pyricularia oryzae on common wheat
ポスター発表
- 令和４年度日本植物病理学会大会, 2022年03月28日いもち病菌非病原力遺伝子PWT7に対するコムギの抵抗性遺伝子Rwt7の単離
- 令和4年度日本植物病理学会大会, 2022年03月Characterization of Pwt2 locus reveals a virulence factor of the blast fungus for wheat infection
- 日本育種学会第140回講演会, 2021年09月25日コムギいもち病抵抗性系統のNBRP 六倍体コムギコアコレクションに おける探索：地理的分布、遺伝的 多様性とゲノムワイドアソシエー ション解析
- ムギ学オンラインセミナー, 2021年04月12日病理学的視点からみた普通系コムギのアジア進出に関する一考察
[招待有り]
- 令和3年度日本植物病理学会大会, 2021年03月普通系コムギならびにそのDゲノム供与種におけるいもち病抵抗性遺伝子の分布とそれらの起源に関する一考察
口頭発表（一般）
- 令和3年度日本植物病理学会大会, 2021年03月コムギいもち病菌に対するペフラゾエート及びイプコナゾールの抑制効果
口頭発表（一般）
- 令和2年度日本植物病理学会関西部会, 2020年11月コムギいもち病菌に対するベノミルの抑制効果
ポスター発表
- 令和2年度日本植物病理学会関西部会, 2020年11月シコクビエいもち病菌が保有するコムギに対する非病原力遺伝子の分子マッピング
ポスター発表
- 12th Japan-US Seminar in Plant Pathology, 2020年10月06日The effect of genomic compartments harboring PWT3 and PWT6, the host-genus specificity determinants of Pyricularia oryzae, on the distribution of their corresponding resistance genes in common wheat
[招待有り]
- 第132回日本森林学会大会, 2020年03月Euwallacea spp. が随伴するFusarium属菌のデイゴとマンゴーへの影響
ポスター発表
- 令和２年度日本植物病理学会大会, 2020年03月Rmg8 and RmgGR119 are effective against the wheat blast fungus (Pyriculari oryzae)in Bangladesh
口頭発表（一般）
- 令和２年度日本植物病理学会大会, 2020年03月シコクビエいもち病菌の非病原力遺伝子PWT6に対するコムギ抵抗性遺伝子Rwt6の詳細マッピング
口頭発表（一般）
- 日本農芸化学会2020年度大会, 2020年03月ズッキーニから同定された汚染物質輸送タンパク質のストレス応答への関与
ポスター発表
- 令和元年度日本植物病理学会関西部会, 2019年09月コムギいもち病菌のオオムギに対する非病原力遺伝子PBY2のクローニング
口頭発表（一般）
- 2019 IS-MPMI XVIII Congress, 2019年07月16日Identification of Rwt6, a wheat resistance gene corresponding to PWT6 which is distributed in Eleusine and Oryza isolates of Pyricularia oryzae.
[招待有り]
- The 8th International Rice Blast Conference, 2019年05月A model for the evolution of new pathotypes in Pyricularia oryzae inferred from host-specialization of the Eleusine subgroup.
ポスター発表
- 平成31年度日本植物病理学会大会, 2019年03月コムギいもち病抵抗性遺伝子Rmg8と相加的に働く新規抵抗性遺伝子RmgGR119の同定
口頭発表（一般）
- 第18回糸状菌分子生物学コンファレンス, 2018年11月コムギいもち病菌のエンバクに対する非病原性の分子解析
[招待有り]
口頭発表（一般）
- The International Training Course on Triticeae Genomics, 2018年10月17日Toward cloning of Rmo2, a barley gene for resistance to various pathotypes of Pyricularia oryzae
[招待有り]
- 第39回日本植物病理学会関西部会若手の会, 2018年09月28日いもち病菌のコムギへの寄生過程の解明と抵抗性育種の方向性
[招待有り]
- 平成30年度日本植物病理学会関西部会, 2018年09月オオムギの各種いもち病菌に対する抵抗性遺伝子Rmo2の１アリル候補配列の機能解析
口頭発表（一般）
- TSL Seminar, 2018年06月05日Elucidating the genetic mechanism of host parasitic specialization of Pyricularia oryzae to wheat
[招待有り]
- 神戸大学研究基盤センター若手フロンティア研究会, 2017年12月いもち病菌と普通系コムギ間の非親和性を支配する非病原力遺伝子のクローニング
ポスター発表
- 平成29年度日本植物病理学会関西部会, 2017年09月コムギいもち病菌に対する新規抵抗性遺伝子の探索
口頭発表（一般）
- NGS現場の会第五回研究会, 2017年05月次世代シーケンサーを用いたbulked segregant analysis法によるシコクビエいもち病菌の普通系コムギに対する非病原力遺伝子のマッピング
ポスター発表
- 平成29年度日本植物病理学会大会, 2017年04月いもち病菌集団内エフェクター分布解析によるシコクビエいもち病菌の普通系コムギに対する新規非病原力遺伝子のクローニング
口頭発表（一般）
- 平成29年度日本植物病理学会大会, 2017年04月コムギいもち病菌の保有するシコクビエに対する非病原力遺伝子の検出と分子マッピング
口頭発表（一般）
- 平成29年度日本植物病理学会大会, 2017年04月エンバクいもち病菌のコムギ品種Hopeに対する非病原力遺伝子のクローニング
口頭発表（一般）
- The 7th International Rice Blast Conference, 2016年10月Cloning of an avirulence gene of an Eleusine isolate of Pyricularia oryzae against common wheat
ポスター発表
- 2016 IS-MPMI XVII Congress, 2016年07月Identification of gene pairs involved in the incompatibility between Eleusine isolates of Pyricularia oryzae and common wheat.
ポスター発表
- 平成28年度日本植物病理学会大会, 2016年03月シコクビエいもち病菌が保有するPWT3ホモログの普通系コムギに対する非病原力遺伝子としての機能の検討
口頭発表（一般）
- 生命情報科学若手の会第7回研究会, 2015年10月次世代シーケンサを用いたbulked segregant analysis (BSA) 法によるシコクビエいもち病菌の普通系コムギに対する非病原力遺伝子の解析
ポスター発表
- 平成27年度日本植物病理学会関西部会, 2015年09月シコクビエいもち病菌の普通系コムギに対する非病原力遺伝子クローニングのためのBC1F1集団の作出および対応する抵抗性遺伝子の座乗候補染色体の検討
口頭発表（一般）
- 平成27年度日本植物病理学会大会, 2015年03月シコクビエいもち病菌が保有する普通系コムギに対する非病原力遺伝子数の遺伝学的推定
口頭発表（一般）
所属学協会
共同研究・競争的資金等の研究課題
- 日本学術振興会, 科学研究費助成事業 研究活動スタート支援, 研究活動スタート支援, 神戸大学, 2022年08月31日 - 2024年03月31日ムギ類－いもち病菌間特異性を支配する抵抗性遺伝子の病原菌認識機構の解明