Chemical communication mechanisms involved in the symbiosis of actinolizal trees and Frankia

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H02254
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 40020:Wood science-related
• Research Institution: Shizuoka University
• Principal Investigator: Shingo Kawai 静岡大学, 農学部, 教授 (70192549)
• Co-Investigator(Kenkyū-buntansha): 米田 夕子 静岡大学, 農学部, 准教授 (90638595)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: アクチノリザル共生 / フランキア / オオバヤシャブシ / 相利共生シグナル化合物 / 環状ジアリールヘプタノイド / 二重結合還元酵素 / ポリケチド合成酵素 / 根毛変形因子

Outline of Final Research Achievements

Actinorhizal trees acquire nitrogen sources early and grow through symbiosis with the nitrogen-fixing actinomycete Frankia. This symbiosis involves cyclic diarylheptanoids (CDH, alnasonol), which are specifically biosynthesized by the tree, as the initial signal substance. We examined polyketide synthase (PKS III), a condensing enzyme of this CDH, and identified the enzyme AsPKS1 involved in diarylheptanoid biosynthesis. In addition, we characterized the enzymes involved in the double bond reductase (DBR) of the diarylheptanoid side chain.
The root hair deformation factor from the Frankia side was partially purified successfully, but its structure could not be analyzed.

Free Research Field

森林生物化学

Academic Significance and Societal Importance of the Research Achievements

アクチノリザル樹木は、窒素固定能を有する放線菌フランキアと根粒共生することで窒素源を早期に獲得し生長することができる。この共生機構の解明は、マメ科とは異なる新しい根粒共生の仕組みを明らかにするとともに、木質バイオマス利用を目指した早生樹の育種に向けた基礎研究となることが期待できる。