玉米叶枕发育及茎叶夹角形成关键基因的挖掘及功能分析

Leaf angle directly affects the size of the planting density, thereby affecting the yield of maize. Understanding the formation and regulation mechanisms of leaf angle has important theoretical significance for maize architecture modification and close planting. Ligule is a key part in maize, whose size, developmental degree and mechanical strength directly affect leaf angle. Therefore, studying the development of leaf ligule, building the networks that control the regulation of ligule development, will greatly facilitate our understanding of the regulation of maize leaf angle. Thus, the project designs to use the classical maize liguleless mutants, e.g. liguleless1, liguleless2 and ligule narrow; polar auxin transporting mutant br2, as well as 31 inbred lines with leaf angle variation, combined with the rapid development of TRAP-seq sequencing technology to study the development of maize leaf ligule. We expect the combination of methods from molecular biology, cell biology, functional biology and bioinformatics will help to understand the regulation mechanisms of ligule development, facilitate the screening of the key genes that control the leaf angle, and provide useful information and candidate genes for maize breeding.

茎叶夹角的大小直接影响玉米种植密度，进而影响玉米的产量。对玉米茎叶夹角进行详细研究，了解其形成和调控的分子机理对玉米株型改良及密植具有重要的理论意义。叶枕是影响玉米茎叶夹角的关键部位。叶枕的大小、发育程度及机械强度直接影响着茎叶夹角的大小。研究叶枕的发育，构建叶枕发育网络调控系统，发掘影响茎叶夹角形成的关键基因，将极大促进我们对玉米茎叶夹角调控的认识。因而，本项目设计利用经典玉米叶枕突变体liguleless1、 liguleless2、ligule narrow, 生长素极性运输突变体br2及31个具有茎叶夹角大小差异的自交系群体，结合快速发展的TRAP-seq技术，对玉米叶枕发育进行详细研究。希望通过分子生物学、细胞生物学、功能基因组学、生物信息学相结合的方法，初步了解叶枕发育的网络调控系统，筛选到调控茎叶夹角的关键基因并对其进行深入研究，为玉米的耐密分子育种提供理论基础和候选基因。

茎叶夹角是决定玉米株型紧凑程度的主要形态指标，叶枕是影响玉米茎叶夹角的关键部位。因而，挖掘影响玉米叶枕生长发育的关键基因，解析玉米茎叶夹角建成的分子机理对玉米株型改良、培育耐密高产玉米新品种具有重要的理论和实践意义。本项目首先采用RNA-Seq高通量测序技术，通过对比平展型和紧凑型自交系以及野生型和茎叶夹角变化突变体叶枕部位的基因表达，明确细胞壁发育相关基因及转录因子表达变化和叶枕发育紧密相关；其次，采用SELEX-seq和ChIP-seq技术相结合的方法筛选出调控叶枕发育的关键转录因子LG2的DNA结合位点，进一步鉴定出LG2可能调控的下游基因；最后，以LG2、LGN蛋白为诱饵，采用酵母双杂交技术（Y2H）筛选出与LG2、LGN互作的蛋白，并通过BiFC和CoIP技术进行了进一步验证。本项目从转录到蛋白水平分析了影响叶枕生长发育的关键基因，为进一步研究叶枕的生长发育进而解析玉米茎叶夹角调控的分子机理奠定了基础。