棉花GbSTK基因调控开花和黄萎病抗性的功能研究

棉花是重要的经济作物,实现既抗病又早熟是棉花重要的育种目标,但棉花抗病与早熟基因之间的关联性研究报道甚少。本课题组前期鉴定到一个响应黄萎病菌诱导的丝氨酸/苏氨酸蛋白激酶基因GbSTK,可以提高转基因拟南芥的黄萎病抗性。本研究发现多个抗病棉花品种中STK基因的表达量显著高于感病对照品种H208。在抗病品种农大601中沉默STK基因,沉默植株在接菌后20d,其黄萎病抗性显著降低,病情指数由27.5(耐病)升高到63.2(感病),表明该基因正向调控棉花黄萎病抗性。对转GbSTK基因拟南芥表型鉴定发现,其开花时莲座叶片数平均为7.5个,显著低于空载体对照植株(11.9个),转基因植株开花时间较对照平均提早5~7 d。进一步对拟南芥开花途径标志基因FT、SOC1和LFY的转录水平检测发现,转基因不同株系中FT和SOC1的表达水平显著高于对照植株,而LFY基因的表达受影响较小,表明STK基因可以影响开花关键基因FT和SOC1的表达,进而调控植株提早开花。基于酵母双杂交互作蛋白筛选试验,初步获得30个与GbSTK具有互作关系的候选蛋白,为进一步揭示GbSTK的分子调控网络奠定了基础。本研究首次鉴定出可同时提高黄萎病抗性和提早开花的一个功能基因,为棉花抗病早熟遗传改良提供了参考依据。

Function study of cotton GbSTK gene in regulating flowering and Verticillium wilt resistance

Cotton is an important cash crop,and achieving disease resistance as well as early maturity is an important breeding goal.However,the molecular relationship between disease resistance and early maturity of cotton is still a research gap.In previous study,we identified a GbSTK gene response to V.dahliae that could enhance Verticillium wilt resistance in transgenic Arabidopsis.In this study,we found that GbSTK was more highly expressed in resistance and/or tolerant varieties than in susceptible varieties.Knocking down of GbSTK expression in Nongda 601 showed that the silenced plants displayed serious disease symptoms,with disease index from 27.5(tolerant)to 63.2(susceptible),suggesting that GbSTK positively regulates cotton Verticillium wilt resistance.More interesting,we found that GbSTK could promote the development of Arabidopsis.At the flowering time point,the average number of rosette leaves in transgenic lines was 7.5,significantly less than the mock plants,and the transgenic plants bloomed five to seven days earlier than the control.The FT and SOC1 gene,regarded as marker genes in Arabidopsis flowering signaling pathway,maintained higher expression level in transgenic lines than in the mock,indicating that GbSTK could accelerate flowering via regulating FT and SOC1 gene expression.We also obtained 30 candidate proteins that could interacted with GbSTK via yeast double hybrid test,which helped to further revealing the molecular regulatory network of GbSTK.Taken together,we first identified a functional gene that could improve disease resistance and early flowering,which would provide a reference for genetic improvement of cotton disease resistant and early maturity.