Molecular mechanisms of resistance genes from wheat and barley recognizing the blast fungus

• Project/Area Number: 22K20580
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0602:Agricultural and environmental biology and related fields
• Research Institution: Kobe University
• Principal Investigator: Asuke Soichiro 神戸大学, 農学研究科, 助教 (90882514)
• Project Period (FY): 2022-08-31 – 2024-03-31
• Project Status: Completed (Fiscal Year 2023)
• Budget Amount: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000); Fiscal Year 2023: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2022: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
• Keywords: いもち病菌 / 抵抗性遺伝子 / オオムギ / コムギ / 非病原力遺伝子

Outline of Research at the Start

オオムギの各種いもち病菌に対する抵抗性は、7H染色体上に座乗する単一の遺伝子座Rmo2のalleleによって支配されている。これまでに本遺伝子の単離に成功し、その病原菌認識範囲は、各alleleが有する特定のドメインによって決定されていることが示唆された。また、Rmo2のコムギホモログはいもち病菌群－コムギ間特異性を決定する抵抗性遺伝子の一つであるRwt7であることが判明し、本遺伝子はムギ類の病害抵抗性において基幹的な役割を担うことが示唆された。本研究では、これら抵抗性遺伝子の病原菌認識機構の解明及びその遺伝子機能進化過程の解明を目指す。

Outline of Final Research Achievements

The barley blast resistance gene Rmo2 and the wheat resistance gene Rwt7 recognize the avirulence genes PBY2 and PWT7, respectively. It was hypothesized that the integrated domain at the N-terminus of Rmo2 and Rwt7 plays an important role in effector recognition. Using protoplast assays with domain swap constructs, it was revealed that the integrated domain of Rmo2 specifically recognizes PBY2, while the integrated domain of Rwt7 specifically recognizes PWT7. Additionally, by screening the effectors of rice and foxtail millet blast fungi based on the three-dimensional structure, we successfully identified an avirulence effector gene recognized by Rmo2.

Academic Significance and Societal Importance of the Research Achievements

NBS-LRR型抵抗性遺伝子に見られるintegrated domainによるエフェクター認識メカニズムが明らかにされる中、本研究では、protein kinase型抵抗性遺伝子における同ドメインのエフェクター認識機構の一端を解明した。
その結果、統合ドメインによる認識拡張が、分子種に依存せず抵抗性遺伝子の分子機能進化において重要な役割を果たすことが示唆された。
この認識機構を応用することで、新たなエフェクターを標的としたムギ類の分子抵抗性育種技術の開発が期待される。

Research Products

• [Journal Article] Loss of <i>PWT7</i>, Located on a Supernumerary Chromosome, Is Associated with Parasitic Specialization of <i>Pyricularia oryzae</i> on Wheat (2023)
  • Author(s): Asuke Soichiro、Horie Akiko、Komatsu Kaori、Mori Ryota、Vy Trinh Thi Phuong、Inoue Yoshihiro、Jiang Yushan、Tatematsu Yuna、Shimizu Motoki、Tosa Yukio
  • Journal Title: Molecular Plant-Microbe Interactions Volume: 36 Issue: 11 Pages: 716-725
  • DOI: 10.1094/mpmi-06-23-0078-r
  • Peer Reviewed / Open Access
• [Presentation] Cloning of Rmo2, a gene for resistance in barley to various host species-specific pathotypes of the blast fungus (2023)
  • Author(s): Soichiro Asuke
  • Organizer: The third barley mutant conference (3BMC)
  • Int'l Joint Research / Invited
• [Presentation] A novel resistance resource found in Sv196, a Turkish accession of barley (Hordeum vulgare), conferring resistance against Triticum isolates of Pyricularia oryzae (2023)
  • Author(s): M Thoihidul Islam, Soichiro Asuke, Hiroshi Hisano, Kazuhiro Sato, Yukio Tosa
  • Organizer: The third barley mutant conference (3BMC)
  • Int'l Joint Research
• [Presentation] Evolution of the wheat blast fungus through stepwise losses of function of avirulence genes partially accompanied by inter-chromosomal translocations (2023)
  • Author(s): Soichiro Asuke
  • Organizer: 12th international congress of plant pathology (ICPP2023 Lyon)
  • Int'l Joint Research
• [Presentation] Molecular basis of the host specificity of Pyricularia oryzae at the plant genus level (2023)
  • Author(s): Soichiro Asuke
  • Organizer: TSL seminar
  • Int'l Joint Research / Invited