兰科植物防御系统蛋白PRs调控菌根形成的分子机制研究

兰科植物是典型的菌根共生植物，其整个生活史都与菌根真菌有着密切的联系。其中，兼具药用和观赏价值的石斛属植物同样需要通过与菌根真菌建立共生关系来完成生活史。前期研究表明，植物PRs蛋白作为植物启动的重要防卫反应系统成员，在防卫致病菌侵染的同时，也在菌根真菌与植物建立共生关系的过程中在免疫、防卫等方面起重要作用。为深入解析PRs蛋白参与兰科菌根共生的调控机制，本项目拟在已有转录组结果的基础上，利用qRT-PCR分析PRs在石斛-真菌共生前后及共生萌发过程的表达特征；以差异表达的PRs为诱饵与石斛-真菌共生体cDNA文库进行酵母双杂交，筛选互作子，利用BiFC技术进行互作验证；开展基因修饰回接试验，明确PRs及其互作子的具体作用。从兰科菌根共生防御策略角度着眼，探讨植物防御系统在兰科菌根共生关系中的发生及调控机制，为兰科植物-微生物互惠共生的协同关系研究提供基础性科学依据。

Orchidaceae are typical mycorrhizal plants, and they are closely related to mycorrhizal fungi during their whole life. Among them, Dendrobium species which have both medicinal and ornamental values, also need to establish mycorrhizal symbionts to complete their life cycles. Previous studies have shown that pathogenesis-related (PR) proteins, as important members of the defense response system in plants, played important roles in immunity and defense during the process of establishing symbiotic relationships between mycorrhizal fungi and plants, as well as in defense against pathogenic fungi. To further analyze the regulatory mechanism of PR proteins in orchid mycorrhiza, following the existing transcriptome results, the expression profiles of PRs during the Dendrobium-Tulasnella symbiotic germination will be studied by qRT-PCR. The interacting factors of the PRs will be screened and verified by yeast double hybridization and BiFC technology. Then the function of these genes will be analyzed by using the mutation/complementation assay and transgenic plant/strain tieback tests. From the perspective of the orchid mycorrhizal defense strategy, the occurrence and regulation mechanism of plant defense system in the growth-promoting relationship of orchid mycorrhiza will be revealed. The results of this study will lay a basic scientific foundation for the study of the synergistic relationship of orchid mycorrhizal mutualisms.