水稻品种间根系化感互作诱导水稻抗稻瘟病的机制

Intercropping can effectively control the occurrence and expansion of field diseases. Numerous studies demonstrated that intercropping can significantly induce the up-regulation of defense-related genes expression in plants and increase resistance against pathogens. Intraspecies intercropping of rice can also effectively reduce disease incidence and severity. However, the mechanism of root allelopathic interactions in rice intercropping system to regulate rice resistance is still unclear. Our previous studies have shown that rice resistance to rice blast can be induced in different rice/rice intercropping combinations, especially the intercropping pattern between Nipponbare and IR64 can significantly increase the defence-related expression of Nipponbare. Meanwhile, exogenous application of root exudates of IR64 into Nipponbare can also significantly increase the resistance of Nipponbare to blast. Therefore, it is speculated that there might be root allelopathic interactions and signal transduction between different rice varieties to regulate rice resistance. Based on the result, we will focus on the mechanism of root allelopathic interaction induce defence against rice blast fungus in rice intraspecies intercropping system. The study will be conducive to further improve the mechanism of biodiversity for disease control, and it will also provide theoretical support for the construction of modern agro-ecological technologies.

多样性间作能够有效控制田间病害的发生和扩展。众多研究发现作物多样性间作能够显著诱导植物防御相关基因的表达上调进而提高作物的抗性水平。不同水稻品种间作也能有效减缓田间病害的发生，然而水稻品种间作系统中根系化感互作诱导调控水稻对病害抗性的机制还不清楚。前期研究发现，不同水稻品种间作能够显著提高水稻对稻瘟病的抗性，尤其是日本晴与IR64间作能够显著提高日本晴的防御表达，同时IR64的根系分泌物也能显著提高日本晴对稻瘟病的抗性，因此推测间作水稻不同品种之间存在根系化感互作及信号转导诱导调控水稻抗性。本项目拟在此基础上深入研究水稻品种间作系统根系化感互作诱导调控水稻抗性水平的机制。本研究的开展有利于对进一步完善利用作物多样性控制病害的原理，也能为利用作物品种多样性间作构建现代农业生态控病技术提供理论支撑。

间作栽培模式下植物根系之间相互作用应答并诱导植物抵抗病原菌侵染是作物多样性种植控制病害的重要机制。课题组前期研究发现，水稻品种多样性间作能够有效减缓水稻稻瘟病在田间的发生流行，然而关于品种间作系统中不同品种之间是否存在根系化感互作并诱导作物提高抗病能力的研究鲜有报道。本项目拟针对水稻品种间根系化感互作诱导水稻抗病性的机制开展研究，探明水稻多样性间作对植株免疫应答和代谢水平的影响，明确根系分泌物在诱导过程中的活性，并探索其作用机制。具体研究结果如下：.（1）水稻品种间作能够诱导植株提高对病原菌的抗性。不同品种间作能够诱导植株体内POX223、CHI、Pr1b、RBBI2等防御相关基因的表达显著上调，通过外源添加间作系统的根系分泌物，证明了根系化感物质是诱导植株抗性的重要物质。.（2）水稻品种间作对植株防御相关的转录和代谢途径调控显著。差异表达基因富集在植物激素转导、植物-病原互作、MAPK信号及苯丙烷生物合成等与植物防御相关途径。同时筛选到月桂酸、反油酸等26种可能与植株抗性相关的差异代谢物质。.（3）月桂酸可能是水稻品种间作系统中诱导植株抗性的关键物质。通过根系分泌物回浇验证其能有效诱导植株抗性基因的表达，利用转录组和代谢组联合分析，挖掘与防御表达显著相关的根系化感物质，并初步验证月桂酸具有显著的抗性诱导活性。.（4）根际微生物可能在根系分泌物的介导下调控植株抗性。不同水稻品种根际微生物区系结构存在显著差异，可能与遗传背景或根系代谢差异有关，这可能为根系化感互作介导调控植物抗性提供帮助。.本项目的顺利开展揭示了品种间作系统中根系化感互作诱导调控作物抗性的机制，对进一步完善利用作物多样性控制病害的原理提供了理论依据，也对利用作物品种多样性间作构建现代农业生态控病技术提供了理论支撑。研究结果能够为进一步科学合理布局和规划遗传多样性种植模式提供理论指导，对保障国家粮食安全，构筑边境生态安全屏障具有重要的理论和实践价值。