2013 Fiscal Year Final Research Report

Study of zygomycete fungus-endobacterium symbiosis

Research Project

Project/Area Number	24780115
Research Category	Grant-in-Aid for Young Scientists (B)
Allocation Type	Multi-year Fund
Research Field	Bioproduction chemistry/Bioorganic chemistry
Research Institution	Osaka Prefecture University
Principal Investigator	KAI Kenji 大阪府立大学, 生命環境科学研究科(系), 助教 (40508404)
Project Period (FY)	2012-04-01 – 2014-03-31
Keywords	エンドバクテリア / 接合菌 / Mortierella alpina / クオラムセンシング / 共生
Research Abstract	Increasing evidence indicates that certain bacteria, namely endobacteria, inhabit fungal cells and establish symbiotic relationships with hosts. However, it has not been clear whether bacterial QS acts in developing the relationships. We isolated and identified C7-HSL and C8-HSL from the culture broth of Mortierella alpina A-178. This suggested the presence of endobacteria in the fungus, which was confirmed by PCR, FISH, and TEM. Two major bands detected by PCR-denaturing gradient gel electrophoresis showed sequence identity with Castellaniella defragrans and Cryobacterium sp. The production ofAHLs depended on the presence of endobacteria and was induced in response to the increase in the concentration of AHLs, suggesting that the bacterium conducts AHL-mediated QS in the fungus. This research is the first to report the production of AHLs by endofungal bacteria and raises the possibility that QS plays roles in the development of fungus-endobacterium symbiosis.