土壤中根系分泌物苯并噁嗪化合物对根结线虫的调控作用

土壤中的根系分泌物在调控根际生物和非生物过程中发挥着重要作用。利用根系分泌物与土壤因子的相互作用来定向控制土传线虫病害已成为新兴农业手段。然而，由于根系分泌物中调控线虫的关键代谢物质还知之甚少，分泌物对线虫的调控过程与土壤因子的相互关系也尚不明确，这严重制约了根系分泌物作为杀线虫剂在生产中的推广和应用。申请人前期研究表明，玉米根系分泌物中的苯并噁嗪类化合物(benzoxazinoids, BXs)能够强烈抑制南方根结线虫的侵染。基于此，本项目以BXs和南方根结线虫为模型，利用一系列BXs突变体植株和不同类型的土壤，剖析BXs中调控线虫侵染的关键组分，解析该组分对线虫的调控机理，并阐明土壤因子对该调控过程的影响，明确该关键组分在农业生产中的应用潜力。本项目的顺利实施不仅会在理论上推进根系分泌物与线虫互作的基础研究，也会在实践上为绿色植物源杀线虫剂的开发、土传线虫病害的克服提供依据和指导。

Root exudates are key regulators of rhizosphere processes. Even though researchers have used the regulating effects of root exudates and soil factors to control soil-borne nematodes in agricultural management, the bioactive metabolites in root exudates are largely unexplored. Our preliminary experiments have shown that benzoxazinoids (BXs) can strongly suppress the infection ability of root-knot nematode (Meloidogyne incognita) in maize (Zea mays) plants. However, which bioactive BX and how this BX mediating nematode suppression are still unknown. Besides, the impacts of the soil factors on this suppression process are unclear. To fill these gaps, we will use the BXs, M. incognita and soil factors as a model system. First, we will use a set of BX-deficient mutants to identify the bioactive metabolite. Then, we will dissect the impacts and mechanisms of this metabolite on the performance and physiology of nematode. Finally, we will investigate the influences of soil factors on the BX-mediated nematode suppression. Taken together, our project will not only push forward the fundamental studies of the molecular mechanisms underlying root exudate-nematode interactions, but also provide an effective and sustainable approach of soil-borne nematode disease management in the field.