Identification of the host target of rhizobial effector and its activation of symbiosis signaling

• Project/Area Number: 19H02860
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 38010:Plant nutrition and soil science-related
• Research Institution: Tokyo University of Agriculture and Technology
• Principal Investigator: OKAZAKI SHIN 東京農工大学, (連合)農学研究科(研究院), 教授 (40379285)
• Co-Investigator(Kenkyū-buntansha): 田淵 光昭 香川大学, 農学部, 教授 (00294637) ; 下田 宜司 国立研究開発法人農業・食品産業技術総合研究機構, 生物機能利用研究部門, 上級研究員 (80415455) ; 林 誠 国立研究開発法人理化学研究所, 環境資源科学研究センター, チームリーダー (30291933) ; 箱山 雅生 国立研究開発法人理化学研究所, 環境資源科学研究センター, 研究員 (60422804)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Project Status: Completed (Fiscal Year 2021)
• Budget Amount: ¥17,290,000 (Direct Cost: ¥13,300,000、Indirect Cost: ¥3,990,000); Fiscal Year 2021: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000); Fiscal Year 2020: ¥6,370,000 (Direct Cost: ¥4,900,000、Indirect Cost: ¥1,470,000); Fiscal Year 2019: ¥6,630,000 (Direct Cost: ¥5,100,000、Indirect Cost: ¥1,530,000)
• Keywords: 共生 / 根粒菌 / マメ科植物 / 3型分泌系 / エフェクター / ダイズ / III型分泌系 / 根粒機

Outline of Research at the Start

申請者らは、マメ科植物と共生する根粒菌が３型分泌系という病原菌と類似の機構によりマメ科植物に感染するという新規共生経路を発見した。本研究では(1)根粒菌エフェクターORF5208の生化学的作用の解析、(2)根粒菌エフェクターの標的宿主植物タンパク質の同定、(3)根粒菌エフェクターにより活性化される宿主植物側遺伝子の同定、(4)ダイズ共生変異体への根粒形成試験、(5)根粒菌エフェクターを発現する形質転換ダイズの根粒形成試験、を行うことで、根粒菌エフェクターによるマメ科植物と根粒菌の新規共生経路の解明を目指す。

Outline of Final Research Achievements

Rhizobial Nod factors (NFs) have been long believed to be essential for legume - rhizobium symbiosis. Bradyrhizobium elkanii USDA61, however, establishes symbiosis with soybean by an effector protein Bel2-5 in the NF-independent manner. In this study, biochemical analysis of Bel2-5 revealed domains involved in interaction with host proteins and induction of nodule formation. In addition, we comprehensively identified host protein candidates that interact with Bel2-5 and host genes whose expression is regulated by Bel2-5. These results revealed the molecular basis of the NF-independent nodule formation mechanism by the effector.

Academic Significance and Societal Importance of the Research Achievements

マメ科植物と根粒菌の共生には根粒菌のNod factor (NF)が必須であると長い間考えられていた。本研究の成果は、根粒菌のエフェクター(Bel2-5)がNF非依存的にマメ科植物の標的タンパク質と相互作用して根粒形成を誘導する機構を世界で初めて明らかにしたものである。今後Bel2-5による根粒形成シグナルの解析をさらに進め、自然界における根粒形成エフェクターの分布や多様性を明らかにすることで、マメ科植物と根粒菌の共進化の一端を明らかにできると期待される。さらに、本エフェクターは、将来的にはイネやコムギなどNF受容機構のない非マメ科植物への根粒形成に貢献することが期待される。

Research Products

• [Int'l Joint Research] フランスの農業開発国際研究セ ンター(フランス)
• [Int'l Joint Research] ガーナ大学(ガーナ)
• [Int'l Joint Research] フランス国際開発研究センター(フランス)
• [Journal Article] Multiple Domains in the Rhizobial Type III Effector Bel2-5 Determine Symbiotic Efficiency With Soybean (2021)
  • Author(s): Ratu Safirah Tasa Nerves、Hirata Atsushi、Kalaw Christian Oliver、Yasuda Michiko、Tabuchi Mitsuaki、Okazaki Shin
  • Journal Title: Frontiers in Plant Science Volume: 12
  • DOI: 10.3389/fpls.2021.689064
  • Peer Reviewed / Open Access
• [Journal Article] Rhizobia use a pathogenic-like effector to hijack leguminous nodulation signalling (2021)
  • Author(s): Ratu Safirah Tasa Nerves、Teulet Albin、Miwa Hiroki、Masuda Sachiko、Nguyen Hien P.、Yasuda Michiko、Sato Shusei、Kaneko Takakazu、Hayashi Makoto、Giraud Eric、Okazaki Shin
  • Journal Title: Scientific Reports Volume: 11 Issue: 1 Pages: 2034-2034
  • DOI: 10.1038/s41598-021-81598-6
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Identification of Bradyrhizobium elkanii USDA61 Type III Effectors Determining Symbiosis with Vigna mungo (2020)
  • Author(s): Nguyen Hien P.、Ratu Safirah T. N.、Yasuda Michiko、Teaumroong Neung、Okazaki Shin
  • Journal Title: Genes Volume: 11 Issue: 5 Pages: 474-474
  • DOI: 10.3390/genes11050474
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Novel rhizobia exhibit superior nodulation and biological nitrogen fixation even under high nitrate concentrations (2019)
  • Author(s): Nguyen Hien P、Miwa Hiroki、Obirih-Opareh Jennifer、Suzaki Takuya、Yasuda Michiko、Okazaki Shin
  • Journal Title: FEMS Microbiology Ecology Volume: 96 Issue: 2
  • DOI: 10.1093/femsec/fiz184
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] The rhizobial type III effector ErnA confers the ability to form nodules in legumes (2019)
  • Author(s): Teulet Albin、Busset Nicolas、Fardoux Joel、Gully Djamel、Chaintreuil Clemence、Cartieaux Fabienne、Jauneau Alain、Comorge Virginie、Okazaki Shin、Kaneko Takakazu、Gressent Frederic、Nouwen Nico、Arrighi Jean-Francois、Koebnik Ralf、Mergaert Peter、Deslandes Laurent、Giraud Eric
  • Journal Title: Proceedings of the National Academy of Sciences Volume: 116 Issue: 43 Pages: 21758-21768
  • DOI: 10.1073/pnas.1904456116
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Presentation] マメ科植物- 根粒菌共生における新規共生経路の解明 (2022)
  • Author(s): 岡崎 伸
  • Organizer: 日本農芸化学会2022年度大会【BBB連携シンポジウム】(招待講演)
  • Invited
• [Presentation] The rhizobial type III effector Bel2-5 plays a dual role in symbiosis with soybean (2021)
  • Author(s): Safirah Tasa Nerves Ratu
  • Organizer: The 30th Annual Meeting Japanese Society of Plant-Microbe Interaction (Online conference: http://jspmi.brc.miyazaki- u.ac.jp/blog/30th-annual-meeting-2021)
• [Presentation] Type III effector of Bradyrhizobium elkanii USDA61 Bel2-5 possesses multiple domains determining symbiotic efficiency with soybeans (2021)
  • Author(s): Safirah Tasa Nerves Ratu
  • Organizer: 14th European Nitrogen Fixation Conference (Online conference: https://events.au.dk/enfc2021/conference)(国際学会)
  • Int'l Joint Research
• [Presentation] Functional analysis of rhizobial pathogenic-like effector hijacking soybean nodulation signaling (2020)
  • Author(s): Safirah Tasa Nerves Ratu, Christian Oliver Kalaw, Michiko Yasuda, Shin Okazaki
  • Organizer: International Conferences on Agriculture and Biological Sciences 2020
  • Int'l Joint Research
• [Presentation] Rhizobium utilizes a pathogenic effector to hijack leguminous nodulation signaling (2019)
  • Author(s): OKAZAKI SHIN
  • Organizer: 5th Asian Conference on Plant-Microbe Symbiosis & Nitrogen Fixation
  • Int'l Joint Research / Invited
• [Presentation] Bel2-5, a type III effector of Bradyrhizobium elkanii hijacking soybean nodulation signaling (2019)
  • Author(s): Safirah Tasa Nerves Ratu, Hien P. Nguyen, Michiko Yasuda, Shin Okazaki
  • Organizer: 5th Asian Conference on Plant-Microbe Symbiosis & Nitrogen Fixation
  • Int'l Joint Research
• [Remarks] 東京農工大学 岡崎研究室
  • URL: http://web.tuat.ac.jp/~okazaki/
• [Remarks] 植物微生物研究室 (岡崎研究室)
  • URL: http://web.tuat.ac.jp/~okazaki/