抗青枯病菌活性成分的发掘及其抗菌机制研究

木麻黄和桉树是我国重要的生态林和经济林树种，而青枯病的大面积发生严重威胁我国的生态安全和相关产业发展，如何防控木麻黄和桉树青枯病是目前亟待解决的重大问题之一。宿主植物、内生菌、病原菌和根际微生物构成一个微生态系统，从微生物中寻找抗青枯病菌活性成分为本项目的研究提供了新的思路。本项目前期已分离并筛选出具有明显抗青枯病菌活性的菌株，而菌株中活性成分类型和化学结构尚不清楚，活性成分的抗菌机理和生物合成途径也亟需阐明。本项目将在前期研究的基础上，构建活性菌株次生代谢产物的分子网络，通过全基因组测序和生物合成基因簇分析发掘未知或沉默表达的化合物，阐明其化学结构，并筛选出有效的抗菌化合物或具有协同增效抗菌作用的化合物；进一步通过转录组测序（RNA-Seq）以及对青枯病菌生长和细胞形态的影响阐明活性化合物抗菌的生理和分子机制。本项目为木麻黄和桉树青枯病的防治以及微生物资源的开发和利用提供重要的理论依据。

Casuarina spp. and Eucalyptus spp. are important ecological and economic forest tree species in China, while bacterial wilt of a large area is a serious threat to our country's ecological security and related industry development. How to prevent and control bacterial wilt of Casuarina spp. and Eucalyptus spp. is one of the major problems to be solved at present. Host plants, endophytic, plant pathogen, and rhizosphere microorganisms constitute a micro-ecosystrm, and looking for active ingredient against Ralstonia solanacearum from microbes provides a new idea for this project. In the early, this project has isolated and screened the significant activity strains against Ralstonia solanacearum. While the types and chemical structures of the active ingredients are unclear, and the antibacterial mechanism and biosynthetic pathway of the active ingredients also need to be elucidated. Based on the previous studies, this project will build the molecular network of secondary metabolites from active strains and discover unknown or silent expression compounds through the whole genome sequencing and biosynthesis gene cluster analysis, and then clarify the chemical structures. In addition, active antibacterial compounds or have synergistic antibacterial compounds will be screened. The physiological and molecular mechanism of antibacterial compounds through the transcriptome sequencing (RNA-Seq) and the influence of cell growth and morphology will be further illustrated. This project will provide an important theoretical basis for the prevention and control of bacterial wilt of Casuarina spp. and Eucalyptus spp. and the development and utilization of microbial resources.