A novely assay of signal transduction on colonization of Ralstonia solanacearum

2015 Fiscal Year Final Research Report

• Project/Area Number: 26660036
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Plant protection science
• Research Institution: Kochi University
• Principal Investigator: HIKICHI YASUFUMI 高知大学, 教育研究部総合科学系環境医学部門, 教授 (70291507)
• Co-Investigator(Kenkyū-buntansha): KAI Kenji 大阪府立大学, 生命環境科学研究科, 助教 (40508404) ; OHNISHI Kouhei 高知大学, 総合科学系, 教授 (50211800) ; KIBA Akinori 高知大学, 総合科学系, 教授 (50343314)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: 植物細菌 / バイオフィルム / クオラムセンシング / 細胞間隙 / コロニー化

Outline of Final Research Achievements

After invading intercellular spaces of roots of tomato plants, Ralstonia solanacearum strain OE1-1 attached on the surfaces of tomato cells vigorously grew there, forming biofilms on tomato cells. The bacterial growth led to activation of the quorum sensing with methyl 3-hydroxymyristate as a QS signal. This led to functioned PhcA, a multi-transcription regulator, which positively regulated not only major extracellular polysaccharide, EPS I, and cell aggregation but also production of a lectin, RS-IIL and secondary metabolites, ralfuranones. RS-IIL was involved in feedback regulation of methyl 3-hydroxymyristate production. Ralfuranones was involved in feedback regulation of PhcA function. PhcA function was involved in biofilm formation which was required for virulence of strain OE1-1. These results indicated that OE1-1 produces mature biofilms on the surfaces of tomato cells after invasion into intercellular spaces, contributing to OE1-1 virulence.

Free Research Field

植物細菌学