内生真菌促布顿大麦分蘖的内源激素调控机理研究

Tillering is the determinant factor of the phenotype and development for gramineae plants, as well as one of the most important agronomic traits that affect plant productivity. Growth and development of tillers are strictly regulated by genetic factors. The initiation and elongation of tiller bud are mainly regulated through plant hormone signaling pathways. We have found that an endophytic fungus, Epichloe bromicola significantly enhanced the tillers in host plant Hordeum bogdanii. We hypothesize that the enhanced tiller in Hordeum bogdanii is the result of modified hormone signaling by Epichloe bromicola colonization. In this proposal, we are going to verify this hypothesis. endophyte-free Hordeum bogdanii will be used as material. Epichloë bromicola hyphae will inoculate the endophyte-free plants. Comparison of plant tillering, phytohormone dynamics, mycelial concentration in endophyte-infected (E+) and endophyte-free (E-) plants will be employed. We will identify involved phytohormones that regulate the enhanced tillering associated with endophytic fungi infection and clarify the modified phytohormone signaling in this process caused by endophytic fungi colonization. The proposed project will provide informative data for creating new gramineous plants with increased tillering in both grass and crop breeding.

禾本科植物分蘖是决定植物株型发育的主要因素，也是影响产量的重要农艺性状。分蘖的生长发育受到遗传因素的严格调控，其主要调控机制是通过植物激素信号通路协调分蘖芽的起始与伸长。申请者课题组前期研究发现Epichloë bromicola内生真菌具有显著提高宿主布顿大麦分蘖的作用，因此项目提出内生真菌能提高其分蘖基于此内生真菌改变了宿主植物激素信号通路这一假设。项目拟采用来源同一基因型的无菌布顿大麦为材料，通过回接布顿大麦内生真菌菌丝的方法获得带菌植株，然后进行带菌和不带菌植株在分蘖形态、激素含量、共生体菌丝浓度的对比研究，探索内生真菌感染与分蘖形态的相关性；揭示内生真菌如何调控宿主植株的激素含量，进一步阐明内生真菌促植株分蘖的相关激素作用机理。通过本课题的研究可为禾本科植物提高分蘖提供新思路，也为此内生真菌用于高产牧草或作物育种奠定理论基础。

禾本科植物分蘖是决定植物株型发育的主要因素，也是影响产量的重要农艺性状。分蘖的生长发育受到遗传因素的严格调控，其主要调控机制是通过植物激素信号通路协调分蘖芽的起始与伸长。项目以Epichloë bromicola内生真菌具有显著提高宿主布顿大麦分蘖为基础，研究该内生真菌布顿大麦共生后对宿主分蘖相关植物激素的影响。项目以来源两个地方基因型的无菌布顿大麦为材料，通过回接温宿布顿大麦内生真菌的方法获得带菌植株，进行了带菌和不带菌植株在分蘖形态、激素含量、共生体菌丝浓度的对比研究，得到内生真菌感染显著提高宿主分蘖数，离体菌中分蘖相关激素含量比共生体中显著低，通过perA基因检测菌丝浓度也验证此结果。内生真菌通过与宿主共生，抑制宿主茎基部的吲哚乙酸，赤霉素、脱落酸含量，促进茎基本细胞分裂素，油菜素内酯和独脚金内酯积累，对茉莉酸含量影响不大。因此得出，内生真菌感染宿主布顿大麦后，是通过调控多激素平衡来促进宿主分蘖的。本课题的结果为禾本科植物提高分蘖提供新思路，也为此内生真菌用于高产牧草或作物育种奠定了理论基础。