内生吡咯伯克霍尔德氏菌诱导杨树抗病性及其机制

Endophytic bacteria are important strain resources of biocontrol, which can effectively colonize internal tissues in plant, play a role of growth enhancement and disease control. Here, the high-efficient endophytic antagonistic bacteria Burkholderia pyrrocinia JK-SH007 with biocontrol activity against poplar canker will be advantaged. Firstly, the inductive substance of JK-SH007 strain will be studied. Secondly, induction of defence responses and genes expression induced in poplar upon colonization by this strain will be carried through transcriptome resequencing technology. Thirdly, assocoated antagnistic genes induced in JK-SH007-colonized poplar will be chosen to make functional verification, helping to explain biocontrol activity of strain JK-SH007. All of these may open the way to explore novel strategies to control poplar diseases. The study will contribute to improve and promote the research associated with molecular mechanisms of induced systemic resistance upon interactions between endophytic bacteria and woody plants, provide a scientific basic for the exploitation and utilization of biological control resources to control poplar diseases, and have important theoretical and practical significance for the promotion of the poplar industry and sustainable economic development.

内生细菌是一类植物病害生物防治的重要菌种资源，能定殖在植物组织内而发挥抗病促生作用。吡咯伯克霍尔德氏菌JK-SH007是一株能高效防治杨树溃疡病，且对杨树具促生长作用的内生细菌，本项目拟以JK-SH007为出发菌株，探索该菌株对杨树诱导抗病性的诱抗物质；采用转录本高通量测序及分析技术研究杨树与JK-SH007菌株互作过程中所发生的遗传反应，获得因JK-SH007菌株定殖而引起杨树表达发生变化的相关抗病基因并进行功能验证，以期在分子水平上揭示JK-SH007菌株对杨树抗病促生机制，为杨树病害的综合防治开辟新的途径。该项研究的深入将有助于完善和推动探究内生细菌与植物互作诱导抗病性的分子机制，将对充分利用植物内生菌资源，提高杨树病害的生物防治能力奠定重要基础。

吡咯伯克霍尔德氏菌JK-SH007是一株能高效防治杨树溃疡病，且对杨树具促生长作用的内生细菌，本项目以该菌株为出发菌株，探索其对杨树诱导抗病性的诱抗物质；并采用转录本高通量测序及分析技术研究杨树与JK-SH007菌株互作过程中所发生的遗传反应，获得因JK-SH007菌株定殖而引起杨树表达发生变化的相关抗病基因并进行功能验证。研究发现，JK-SH007菌株的挥发性物质不仅对JK-SH007菌株产生的VOCs对3种杨树溃疡病病原菌(金黄壳囊孢菌、拟茎点霉菌和七叶树壳梭孢菌)有强烈的抑菌作用，而且对杨树具有明显的诱导抗病性。采用顶空SPME-GC-MS法分析JK-SH007菌株发酵液中VOCs，主要包括13种成分，其中，二甲基二硫化物（DSDM）所占的比例最大。与其他挥发性物质相比，DSDM为诱导杨树产生诱导的最佳诱导物质，DSDM对病原菌具有强拮抗作用。DSDM作用杨树组培苗后导致杨树防御酶活性和多酚含量增加，MDA含量下降；同时，该物质对杨树具有一定的促生长作用。将DSDM作用的杨树苗进行转录组测序，获得与抗病相关的差异表达候选基因共129个,生长相关基因129个。通过RNA干扰技术最终确定了2个候选抗病基因的功能分别与杨树β-1,3 葡聚糖酶合成及细胞壁木质素合成相关。以上研究结果在分子水平上揭示了JK-SH007菌株对杨树抗病促生机制，为杨树病害的综合防治开辟新的途径。该项研究的深入将有助于完善和推动探究内生细菌与植物互作诱导抗病性的分子机制，将对充分利用植物内生菌资源，提高杨树病害的生物防治能力奠定重要基础。