玉米ZmYGL-1基因在叶绿体发育中的功能研究

Leaf is the main organ of maize photosynthesis and leaf color is the important factor that affects the efficiency of photosynthesis, improving the efficiency of photosynthesis is of great significance to improve the dry matter accumulation. Our research group obtained a novel yellow-green leaf mutant ygl-1 in maize, its chloroplast development was retarded and the efficiency of photosynthesis significantly reduced. The candidate gene ZmYGL-1 of the yellow-green leaf mutant ygl-1 was obtained through map-based cloning, encoding the chloroplast signal recognition particle 43kDa protein, and genetic transformation complementary experiments also verified the functional gene. On this basis, the aims of this proposal are: exploring the functions of ZmYGL-1 during chloroplast development in maize using the double mutant; constructing vectors of over-expression and RNAi, CRISPR/Cas9 gene edit for ZmYGL-1, and genetic transforming into maize, clarifying the effects of the different expression levels of ZmYGL-1 on chloroplast development, photosynthetic efficiency and dry matter accumulation; revealing the regulatory networks by identifying differentially expressed genes between parents and their NILs(near isogenic lines) by the transcriptome sequencing; clarifying the metabolic pathways by screening of interaction protein molecules of ZmYGL-1 by yeast two-hybrid. This project will reveal the functions and molecular regulatory networks of ZmYGL-1 during chloroplast development in maize, and lay the foundations for the elite alleles mining and molecular design breeding.

叶片是玉米光合作用的主要器官，而叶色是影响光合作用效率的重要因素，提高光合效率对提高干物质积累具有重要意义。课题组获得一个新的玉米黄绿叶突变体ygl-1，其叶绿体发育受阻，叶片光合效率显著降低。采用图位克隆技术获得了该突变体的候选基因ZmYGL-1，该基因编码叶绿体信号识别颗粒43kDa蛋白，遗传转化互补实验也验证了功能基因。在此基础上，本项目拟研究：利用双突变体探讨ZmYGL-1在玉米叶绿体发育中的作用；构建ZmYGL-1的过表达和RNAi、CRISPR/Cas9基因编辑载体，并遗传转化玉米，明确其不同表达水平对叶绿体发育、叶片光合效率以及干物质积累的影响；利用转录组技术研究亲本及其近等基因系间差异表达基因，揭示其调控网络；利用酵母双杂交筛选与其互作的蛋白分子，明确其代谢途径。本项目将揭示ZmYGL-1在玉米叶绿体发育中的功能及其分子调控网络，并为优异等位基因挖掘和分子设计育种奠定基础。

叶绿体是玉米进行光合作用的重要场所，而有关叶绿体发育相关基因及其功能的研究较少。课题组前期通过图位克隆技术获得了玉米叶绿体发育相关基因ZmYGL-1。在这儿，构建了ZmYGL-1的转基因载体，并遗传转化玉米，明确了其分子生物学功能；对近等基因系进行了RNA-Seq，鉴定差异表达基因并揭示了其遗传调控网络；构建了酵母文库，并筛选到与其互作的蛋白分子；构建了双突变体，并明确了ZmYGL-1在玉米叶绿体发育中的重要地位和作用；构建了亚细胞定位载体并进行原生质体转化，明确了其在细胞中的定位和作用位点。这些结果揭示了玉米ZmYGL-1基因在叶绿体发育中的功能及其调控网络，将为选择理想的玉米育种提供基础。