根际有益菌在作物根表形成生物膜的机理模型与调控研究

项目名称： 根际有益菌在作物根表形成生物膜的机理模型与调控研究

项目编号： No.31330069

项目类型： 重点项目

立项/批准年度： 2014

项目学科： 植物保护学、园艺学与植物营养学

项目作者： 沈其荣

作者单位： 南京农业大学

项目金额： 312万元

中文摘要： 根际有益菌在促进植物生长及防控土传病害方面的应用日益受到重视，施用根际有益菌是减少农用化学品投入的重要途径之一，有益菌在植物根际的有效定殖和成膜是其发挥功能的前提。芽孢杆菌拥有一整套复杂的生物膜形成调控机制，而根系分泌物中的信号分子能通过调控其生物膜形成而影响根际定殖和成膜行为。本项目以实验室分离并已广泛应用的根际有益菌Bacillus amyloliquefacien SQR9（SQR9）为材料，研究其不同突变体在不同作物根系的定殖和成膜特征，及其促生和防控土传病害的效果；DegU不同磷酸化水平、转录因子AbrB及其他因子在SQR9成膜中的分子机制及与根系分泌物的互作效应；SQR9及突变体响应不同作物根系分泌物的转录组差异。揭示根系分泌物调控SQR9在作物根表定殖及成膜的分子机理模型，为增强SQR9在根际的定殖和成膜能力提供理论依据，也为国内开展PGPR的分子研究提供思路与技术支撑。

中文关键词： 根际有益菌;根表;定殖;生物膜;调控机理

英文摘要： Application of plant growth-promoting rhizobacteria (PGPR) in stimulation of plant growth and suppression of soil-borne diseases is receiving more and more attention. Effective application of PGPR is an important strategy for decreasing of chemicals input. Efficient colonization of beneficial microbes on plant roots or rhizosphere plays vital role for their function performance. Bacillus spp. hold a complex regulation model for biofilm formation, as the signal molecular in the root exudates of plant could affect the colonization behavior of Bacillus by regulating their biofilm formation. Bacillus amyloliquefacien SQR9 (SQR9) has been screened and successfully used as a PGPR in bio-organic fertilizers. The strain can significantly promote plant growth and has a high antagonistic ability to soil-born pathogens as well. This project will study the rhizosphere colonization of SQR9 in different plants, such as cucumber, maize, and banana and biocontrol behavior of its differernt mutants (the mutants with different phosphorylation level of DegU, deficient of abrB, deficient of bmyD, and so on). The influence and related mechanism of different phosphorylation level of DegU, transcription factor AbrB, as well as other regulators on biofilm formation of SQR9 will be evaluated. The interaction mechanism between root exudates and the several mutants will also be investigated, especially on the roles of different root exudates on the transcriptional profiling of SQR9 and the mutants. The main goal of this study is to reveal the detailed molecular mechanism regarding colonization and biofilm formation of SQR9 on plant roots. This research will provide the theoretical instructions for improving the root colonization and agricultural application of SQR9. Also we can provide domestic researchers with molecular technology on PGPR.

英文关键词： Rhizosphere beneficial microbe;Root surface;Colonization;Biofilm;Regulation mechanism