植物伯克霍尔德氏菌（Burkholderia plantarii）是引起水稻秧苗细菌性立枯病的重要病原菌之一，其侵染性强、繁殖力强、适应性强，严重威胁我国水稻生产。目前，如何有效防治水稻秧苗细菌性立枯病仍是一个有待于解决的难题。Burkholderia heleia PAK1-2为申请人从水稻根际筛选的一株能高效防治水稻秧苗细菌性立枯病的生防细菌，但其生防机制仍不清楚。前期研究发现B. heleia PAK1-2分泌的次生代谢产物中含非抗菌性的种间信号分子，其可能通过干扰B. plantarii群体感应（QS）系统来抑制致病力。本项目将分离、纯化和解析B. heleia PAK1-2种间信号分子的结构和相对构象，明确其对B. plantarii QS系统的作用机制及病害防治效果。研究结果将为进一步构建水稻秧苗细菌性立枯病的防治体系提供重要基础，也为开发新型的微生物杀菌剂提供一种重要途径。

Burkholderia plantarii is an important causal agent of bacterial seedling blight of rice. This pathogen is of strong infectivity, reproductive capacity and adaptability, and thus poses a serious threat to rice production in China. However, it is still obscure how to effective control bacterial seedling blight of rice caused by B. plantarii. To address this issue, Burkholderia heleia PAK1-2 was isolated from rice rhizosphere and found to be a potent biocontrol agent against B. plantarii, of which the mechanism remains to be elucidated. During the previous investigation, the non-antibacterial interspecies signaling molecule from secondary metabolites produced by B. heleia PAK1-2 was preliminarily focused, since this principle suppressed the pathogenicity of B. plantarii through possible inactivation of the quorum sensing system. In the current work, we aim to isolate, purify and identify the active interspecies signaling molecule from B. heleia PAK1-2, and also elucidate the mechanism of action by which quorum sensing system of B. plantarii was targeted. Our results will serve as an important basis for development of control strategy against seedling blight of rice and also provide an important mean for exploration of novel microbial bactericide.