玉米雄性不育基因male sterility 54的生物学功能与作用机理解析

Male sterility is a widespread phenomenon in angiosperms, which has been successfully applied to achieve heterosis. Early research in our team found a mutant which shows male sterility with abnormal pollen, termed as male sterility 54 (ms54). Furthermore, we isolated the gene by map-base cloning, which encodes a Lysin motif (LysM)-containing protein. In the project, our objectives are: i) to construct the over-expressed and CRISPR vectors of candidate genes Ms54, and then introduce into maize C01 line. Next, we will examine the phenotype carefully to reveal the biological function. ii) to explore the localization and pattern of Ms54 expressed during the development of anthers and microspores by qRT-PCR and RNA in situ hybridization, reveal the interacting proteins by immunoprecipitation assay and validate the interaction by yeast-two hybrid system and/or the bimolecular fluorescence complementation (BiFC) assays. iii) to comparative analyze the differentially-expressed genes in mutant anther compared to wild-type by mRNA-seq to indicates a Ms54-involved regulatory pathway. These researched are contributed to clarify the biological function of Ms54 and molecular regulatory mechanism of maize anther development, to provide germplasm resources and theoretical basis for maize heterosis utilization.

雄性不育是一种在被子植物中广泛存在的现象，也是研究作物杂种优势利用的重要农艺性状。本项目组前期发现一个玉米花粉异常发育的雄性不育突变体，暂命名为male sterility 54 (ms54)，并通过图位克隆技术确定该基因编码一个含有LysM基序的蛋白。本项目拟通过遗传转化及转基因后代遗传分析解析Ms54的生物学功能；采用qRT-PCR和RNA原位杂交分析明确Ms54特异表达的组织区域；使用免疫沉淀、酵母双杂交和双分子荧光互补技术鉴定与Ms54互作蛋白；结合突变体和野生型转录组比较分析，明确Ms54的调控途径以期阐明Ms54生物学功能和作用网络及其调控玉米花药发育的分子机理，为玉米杂种优势利用提供种质资源和理论依据。

玉米是重要的粮食作物，杂种优势的利用可以显著提高玉米的产量，而雄性不育系的利用是玉米杂种优势利用的有效手段。本研究发现一个玉米核不育突变体ms54，在花粉母细胞减数分裂中有一对同源染色体滞留赤道板附近，迁移速率明显滞后，导致小孢子液泡化严重，花粉细胞皱缩降解；遗传分析发现是由一对隐性基因控制，图位克隆该基因编码一个含有LysM结构域的GPI锚定蛋白，主要在花粉母细胞减数分裂过程的绒毡层和小孢子母细胞中表达；遗传转化证明该基因的生物学功能并能互补突变体表型；多组学证明Ms54与GPI锚定蛋白互作，调控HD-ZIPs等转录因子家族的表达，通过调节花药及小孢子母细胞中激素信号转导以及脂肪、类胡萝卜素等次生代谢物的合成控制绒毡层和花粉形成。不仅有助于解析玉米花药发育的分子机理，而且也为玉米杂种优势利用提供种质资源和理论依据。