蓝铜蛋白(BCP)调控棉纤维细胞发育的机制研究

Cotton is the most important fiber crop for the textile industry in China. Apart from their economic importance, cotton fiber also provides a unique single-celled model system for studying regulatory mechanisms of cell elongation in the absence of cell division. Blue copper-binding proteins (BCPs), which are ancient and widely distributed throughout the microorganism and plant kingdom, include a single polypeptide chain that binds a single type I copper atom. However the molecular mechanisms of this type of proteins regulating fiber cell development still remains largely unclear. In our previous study, we identified several cotton BCP genes which are involved in fiber development. And it was found that these proteins (BCPs) can interact with PIP2 proteins and regulate their activities through yeast two-hybrid analysis. In this project, we will investigate the roles of the isolated BCPs and their signaling pathway in fiber development. The mechanism of the interaction between BCP and PIP2 proteins will also be further studied to reveal how it affects the quality of fiber through in vitro, Arabidopsis and cotton systems. This study will be benefit to understanding the molecular mechamism of fiber cell differentiation and development, and also provide some new scientific data and genes (proteins) for improving cotton fiber quality.

棉纤维细胞起源于单个种子表皮细胞，它不仅是重要的纺织原料，也是研究细胞极性生长的理想模型之一。蓝铜蛋白(BCP)是一类铜离子结合蛋白，广泛存在于植物和微生物中，这类小分子调节蛋白在棉纤维发育中的作用目前尚无报道。在前期工作中，我们鉴定了多个棉纤维发育相关的BCP蛋白，研究发现该类蛋白能够调节PIP2 类水孔蛋白的活性。在此基础上，本项目将着重研究BCP 蛋白在棉纤维发育中的功能，拟选择体外、拟南芥和棉花三种体系研究BCP对PIP2蛋白活性的调控机理及其影响棉纤维细胞发育及品质性状的信号调控途径。本研究将有助于深入了解BCP蛋白调控棉纤维细胞发育的分子机制。同时, 也可为棉纤维品质改良提供重要科学资料及重要功能基因。

棉纤维细胞起源于单个种子表皮细胞，它不仅是重要的纺织原料，也是研究细胞极性生长的理想模型之一。蓝铜蛋白(BCP)是一类铜离子结合蛋白，在前期工作中我们从棉花中分离得到了一个纤维优势表达基因GhBCP4。该项目拟从棉纤维优势表达基因GhBCP4入手，研究目标基因在纤维发育中的作用，同时分离鉴定目标蛋白的相互作用蛋白，研究BCP蛋白对棉纤维细胞发育的调控机理。过量表达GhBCP4的转基因棉花植株纤维长度增加，而GhBCP4-RNAi转基因植株棉纤维长度变短。对WT、GhBCP4-OE及GhBCP4-RNAi 的12DPA纤维的总RNA进行转录组测序，分析三者间差异表达基因，结果显示在GhBCP4-OE纤维细胞中，上调基因主要包括与乙烯、生长素、JA等激素的合成及信号传导相关基因，而下调基因主要为次生壁合成相关基因及参与次生壁发育调控的转录因子。这些基因在GhBCP4-RNAi样品中表达趋势刚好相反。为阐明GhBCP4调控棉纤维细胞发育的分子机理，我们利用酵母双杂交系统和双分子荧光互补技术筛选鉴定了多个GhBCP4的互作蛋白，其中包含两个CrRLK激酶（GhCrRLK1 和GhCrRLK3）。CrRLK激酶定位于细胞壁上，负责接收细胞壁信号并调控植物细胞次生壁的发育。以上结果表明GhBCP4过量表达能促进纤维细胞中乙烯、生长素的合成，激发乙烯、生长素应答基因的表达；同时GhBCP4还可能协同CrRLK激酶，抑制或延缓次生壁的发育，从而促进细胞的伸长，提高棉纤维的长度。