Expression and function of stress-response gene induced during rhizobial and arbuscular mycorrhizal symbioses in soybean roots

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K07637
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Plant nutrition/Soil science
• Research Institution: Chiba University
• Principal Investigator: Sakamoto Kazunori 千葉大学, 大学院園芸学研究科, 教授 (10225807)
• Co-Investigator(Kenkyū-buntansha): 園田 雅俊 千葉大学, 大学院園芸学研究科, 講師 (70376367)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 二重共生 / ストレス応答 / メタロチオネイン遺伝子 / ダイズ / 根粒菌 / アーバスキュラー菌根菌 / 活性酸素種

Outline of Final Research Achievements

We investigated the expression and function of type 1 metallothionein gene (GmMT1) induced during rhizobial and arbusculer mycorrhizal (AM) symbioses in soybean roots. The results obtained were as follows. (1) The expression level of GmMT1 of root and nodule at pod formation stage were higher than that at flowering stage. (2) The expression of GmMT1 in the root was found at the surrounding host cell of arbuscule of AM fungi colonized. Meanwhile, the expression of GmMT1 in the nodule was found at the surrounding host cell of bacteroidal infection area. (3) RNAi knock-down of GmMT1 led to significant suppression of AM fungal colonization and nodule formation and an increase in hydrogen peroxide content in soybean root. Based on the results obtained, we suggest that GmMT1 eliminates reactive oxygen species occurred in AM root and nodule, and protects symbiotic organs from oxidative stress.

Free Research Field

植物栄養学　根圏微生物学　土壌微生物学

Academic Significance and Societal Importance of the Research Achievements

本研究によって得られたType1メタロチオネイン遺伝子の発現特性とその役割に関する知見によってダイズの根粒・菌根二重共生系の成立メカニズムの一端が分子レベルで明らかにされ、高い学術的貢献がなされた。本研究の成果は、今後二重共生系を強化した低肥料性・ストレス耐性ダイズの分子育種に関する研究に発展させることができ、土壌劣化や異常気象に対応した農業技術への貢献が期待される。