玉米褐色叶中脉突变体Brown Midrib 6 (bm6)的图位克隆和功能解析

木质素是玉米中重要的存储物质，其合成通路中的关键酶和调控机制已有大量报道，然而与其协同互作的调控途径还未有报道。玉米褐色叶中脉突变体（Brown Midrib bm6）能够显著降低木质素合成单体的含量和比例，申请人团队在前期的基础上通过图位克隆的方法克隆了bm6突变体候选基因（GRMZM2G062420），编码一个GTP环水解酶，推测bm6参与调控一碳代谢合成通路，影响甲基的供体合成。在此基础上本项目拟利用Mu突变体插入系统、EMS诱变、转录组、代谢组和甲基化等多种遗传学和组学的手段，深入解析bm6在一碳代谢途径的核心调控模式和互作方式，明确一碳代谢与木质素合成途径的协同作用和互作机制，进而在源头上改变G型和S型木质素单体的含量及比例，为培育优质高效的能源型和饲用型玉米新品种奠定理论基础。

Lignin is one of the most important storage materials in maize. Previous studies on lignin biosynthesis have found the key enzymes and its regulatory mechanisms. However, little is known about potential pathway synergistically interacted with lignin. The maize brown midrib 6 (bm6) can significantly reduce the content and the ratio of monomer in lignin. Based on our previous studies, the bm6 candidate gene (GRMZM2G062420) was cloned by map-based cloning method. Due to its role of encoding a GTP cyclohydrolase, the bm6 may regulate the synthesis of methyl in one carbon metabolism pathway. Here, we are going to integrate the Mu mutant insertion system, EMS mutagenesis, transcriptome, metabolism, and methylation analyses to decipher the potential key regulatory network of bm6 as well as its synergistically interacted network in one carbon metabolism pathway, thus genetically modify the proportion of lignin monomer G/S type. This study highlights the bm6 regulatory network of important lignin pathway and provides potential targets for silage-variety breeding applications.