拟南芥类萌发素蛋白AtGLP3的功能分析及其在BR信号途径中的作用研究

油菜素甾醇类物质（Brassinosteroids, BRs）通过调节下游靶基因的表达影响植物生长发育，因此研究BR信号网络的精细调控对于解析植物激素信号转导网络具有重要意义。本课题组在前期工作中筛选到一个BZR1靶基因- - 类萌发素家族成员AtGLP3，其表达受BR和IAA抑制。过量表达AtGLP3增强转基因植株对BR和IAA的敏感性，同时部分抑制BR不敏感突变体bri1-5的表型；此外，AtGLP3还参与调控BR响应基因DWF4和生长素响应基因SAUR-AC1的表达，说明AtGLP3参与BR和生长素的信号途径。本项目拟利用遗传、分子和生化手段对AtGLP3的功能及其与激素（如BR、生长素等）的关系进行研究，初步探讨AtGLP3在激素（如BR、生长素等）介导的生理反应中的作用机制，为阐明激素调控植物生长发育的分子机制和农作物重要农业性状改良提供依据。

Brassinosteroids (BRs) affects growth and development of plants by regulating the expression of downstream genes, which is of great importance for investigating the elaborate regulations on hormone signaling pathways and improving agronomic traits of crops. We identified a member of germin-like protein family, AtGLP3, as one of the BZR1 target genes in our preliminary studies. BR and IAA treatments decrease AtGLP3 mRNA level, while overexpression of AtGLP3 could increase the sensitivity of transgenic seedlings to both BR and IAA, and partially inhibit the dwarf phenotype of BR-insensitive mutant bri1-5. In addition, AtGLP3 involved in the regulation of BR- and aunxin-response genes as DWF4 and SAUR-AC1 expressed oppositely in GLP3-OX and RNAi seedlings, suggesting that AtGLP3 might be involved in BR and auxin signaling pathway. The present study is designed to investigate potential functions of AtGLP3 and correlations with other phytohormones, and identify its interacting components by genetic and biochemical tools. The results will help us in further elucidating the molecular mechanism of phytohormone signaling regulation and provide further evidence for increasing crop production by modulating phytohormone signaling network.