链霉菌JD211诱导水稻抗真菌性病害的生理及分子机理

So far, a variety of bacterial and fungal taxa have been found, which can promote the growth of higher plants as well as improve their disease resistance and stress tolerance.However,the Streptomyces with rich secondary metabolites that could promote disease resistance ability of plants were rarely systematic reported. In the preliminary research, cycloheximide from Streptomyces naraensis JD211 could strongly inhibit the plant pathogenic fungi.Streptomyces JD211 has disease prevention and control, and growth promotion effects on rice, and changed the rhizosphere microbial community structure, but the mechanism of promoting disease resistance in the soil- plant system is unclear.In this project, Streptomyces JD211 was used as the research object.we have researched on Streptomyces JD211's defense role in regulating gene and related proteins of rice through the interaction process of rice and rice blast fungus from the perspective of physiological, biochemical and molecular biology,respectively.Thus, we can clearly define its ecological function of Streptomyces JD211 and its interaction mechanism with plants, which is very important significance in the mechanism of action about Streptomyces disease prevention and promotion. This project not only has a theoretical value of the development of environmental protection and safety production of anti-microbial agent, but also provides a feasible way for the sustainable development of agriculture.

迄今为止，已发现了多种能够促进高等植物生长、提高抗病和耐逆的细菌、真菌类群，但具有丰富次级代谢产物的链霉菌对植物的促生抗病作用却少见系统的报道。前期研究发现奈良链霉菌JD211所产次级代谢产物环己酰亚胺类物质对植物病原真菌有较强的抑菌作用，链霉菌JD211对水稻有抗病促生效应，且改变了根际微生物群落结构。但该菌在土壤-植物体系中抗病促生的作用机理不清楚。本项目以链霉菌JD211为研究对象，分别从生理生化和分子生物学的角度，研究水稻与稻瘟病菌互作过程中链霉菌JD211对水稻防卫基因及相关蛋白调控作用的影响，在此基础上阐明链霉菌JD211对水稻的促生抗病机制，为明确拮抗菌的生态功能及其与植物互作的机理奠定理论基础。此项研究不仅对开发环保、安全的生防菌具有理论价值，而且可为农业可持续发展提供一条可行途径。

在同一生育时期，接种低浓度链霉菌JD211的水稻秧苗在叶长、叶宽、苗高、整齐度、基宽、主根长、根数、白根数、根活力、地上鲜重、地下鲜重、根冠比、充实度、茎叶NPK积累量、茎叶及根可溶性糖含量等方面均存在明显优势。.施加链霉菌JD211栽培水稻降低了水稻秧苗的稻瘟病发病率，提高防效。同时提高了叶片过氧化氢酶活性、脂氧合酶活性、H2O2含量及叶片细胞膜透性；链霉菌JD211能够有效调控植物细胞过敏性反应，诱发植物细胞过敏性坏死，阻止病原菌侵染；提高了水稻木质素、类黄酮、总酚含量以及过氧化物酶、多酚氧化酶、苯丙氨酸解氨、几丁质酶、β-1,3-葡聚糖酶活性，促进了酚类物质积累，诱导酶活性上升，提高水稻抗病性。.链霉菌JD211对编码水稻过氧化氢酶、苯丙氨酸解氨酶、几丁质酶、病程相关蛋白PR-1的基因CatA、PAL、Rcht2、Prla表达量均有影响，链霉菌JD211对CatA、PAL基因表达有一定的促进作用，提高了Rcht2基因表达量，且加入链霉菌JD211浓度越大，越快激发Rcht2的表达。.利用iTRAQ定量蛋白组学技术分析水稻叶片蛋白差异，共鉴定到3062个可信蛋白，其中链霉菌JD211诱导产生213个差异蛋白，主要涉及乙醛酸盐代谢、碳合成、卟啉与叶绿素代谢等途径。在接种稻瘟病菌链霉菌JD211诱导产生158个差异蛋白，主要涉及乙醛酸盐代谢、碳代谢、光合作用、光合作用天线蛋白代谢等途径。发现链霉菌JD211诱导抗性主要与叶绿素合成、乙醛酸盐代谢、信号传导以及酚类物质合成有关，说明链霉菌JD211可快速激活水稻对病原菌的识别，激发水稻自身抗性反应，合成酚类物质，同时促进植物能量合成，共同对植物起保护作用。.本项目研究了水稻与稻瘟病菌互作过程中链霉菌JD211调控水稻过敏性反应；影响酚类物质代谢和病程相关蛋白活性；调控有关防卫基因及相关蛋白。在此基础上阐明了链霉菌JD211对水稻的促生抗病机制，为明确拮抗菌的生态功能及其与植物互作的机理奠定坚实的理论基础，对进一步研发具有我国自主知识产权的生防菌剂，具有重大的理论研究和实践应用价值。