棉花是重要的纤维作物，成熟棉纤维的次生壁含有已知植物中最高比例的纤维素含量（超过90%）。尽管已经分离了多个编码棉纤维次生壁纤维素合酶（Cellulose Synthase A, GhCESA）的基因，但它们精确的转录调控机制还不清楚，到目前为止还未见特异调控GhCESA的转录因子的报道。我们在前期工作中识别了1个可能特异调控棉纤维次生壁纤维素合成的GhFSM1转录因子，初步实验分析显示它能激活次生壁GhCESA启动子，也能影响棉纤维次生壁厚度。本项目拟从该基因入手，深入分析其在棉纤维次生壁纤维素合成过程中的功能，鉴定GhFSM1与次生壁GhCESA启动子结合的特异元件，识别GhFSM1的上游调控蛋白及互作蛋白，揭示GhFSM1调控次生壁纤维素合成的基因调控网络。本研究结果不仅为纤维作物的次生壁调控机制提供理论依据，也为改良棉纤维品质分子育种提供基因元件。

Cotton is one of the most important fiber crops worldwide. The mature cotton fiber secondary wall has the highest percentage of cellulose known in plants (>90%).Though progress on secondary cell wall cellulose synthase A (CESA) genes involved in cellulose synthesis has been made, our knowledge of the precise regulatory mechanisms that give rise to cellulose remains a mystery. Up to now,transcription factors that specifically regulate secondary cell wall cellulose synthesis has not been identified. Our previous studies identified one GhFSM transcription factor that might specifically govern cotton fiber secondary cell wall cellulose biosynthesis. Our preliminary experimental results showed that this transcription factor was able to activate the promoters of secondary cell wall GhCESAs, and affected fiber cell wall thickness as well. In this study, the roles of this GhFSM1 in fiber secondary cell wall cellulose synthesis will be clarified in detail, the specific core cis-element in GhCESA promoters that GhFSM1 bind to will be characterized; Furthermore, upstream regulatory proteins and interacting partners of GhFSM1 will be identified and gene regulatory network which controls fiber secondary cell wall formation will be revealed. Our findings are not only beneficial to understand the regulation of secondary wall cellulose biogenesis for numerous cellulose-rich fiber crops, but also provide strategies to improve the quantity and quality of cotton fiber.