玉米抗茎腐病基因ZmAuxRP1的功能和抗病机理

A maize auxin regulated protein (AuxRP) encoding gene ZmAuxRP1was cloned by fine-mapping, the genomic variation and the different expression level of ZmAuxRP1 after inoculation were finished. The transgenic maize plants that contained the ZmAuxRP1 RNAi or enhanced expression under the control of promoter CaMV35S and the ZmAuxRP1 complement vector were obtained and self-crossed to produce different kinds of transgenic maize plant populations, which will be used to investigate the effect of different expression level of ZmAuxRP1 on maize resistance to Gibberella stalk rot and root growth. The subcellular localization of ZmAuxRP1 will be investigated. With the transgenic maize plants that contained increased or decreased expression level of ZmAuxRP1 and the near isogenic lines that obtained from high generation backcross populations, transcriptome analysis and metabonomic determination will be used to investigate the molecular mechanism of the candidate gene ZmAuxRP1 that confers resistance to Gibberella stalk rot in maize. At the same time, the transgenic Arabidopsis that contained ZmAuxRP1 or its Arabidopsis ortholog GFP fusions under CaMV35S were obtained and crossed with the reporter transgenic line DR5:GUS, the effects of AuxRPs on plant growth and development, the accumulation and distribution of auxin in different tissue during plant development will be investigated. With all these results obtained, the biological function and molecular mechanism of the candidate gene ZmAuxRP1 that confers resistance to Gibberella stalk rot in maize will be explained.

玉米茎腐病是全球范围内普遍发生，且严重危害玉米生产的真菌病害。经过连续多年研究,我们已通过精细定位克隆了一个玉米抗茎腐病基因ZmAuxRP1。本项目已完成该新型玉米生长素调节蛋白编码基因ZmAuxRP1的BAC文库筛选与BAC测序且明确其基因组结构变异为基础。以已经获得的含有ZmAuxRP1基因RNAi干扰、功能互补和过表达等载体转基因玉米群体以及抗感近等基因系为材料，详细分析并明确ZmAuxRP1表达变化对玉米根发育和抗病反应之间的关系。利用瞬时表达以及转基因稳定表达分析ZmAuxRP1基因在玉米原生质体以及不同玉米组织细胞中的亚细胞定位。同时依据其亚细胞定位结果，设计一系列代谢途径和生长素运输等抑制剂处理各种转基因玉米和抗感近等基因系，检测玉米生长发育和抗病等性状；同时以高代纯合的各种转基因玉米和接种后的抗感近等基因系为材料进行转录组测序和代谢组测定，探索ZmAuxRP1作用途径和机理

玉米茎腐病是全球范围内普遍发生，且严重危害玉米生产的真菌病害。经过连续多年研究,我们已通过精细定位克隆了一个玉米抗茎腐病基因ZmAuxRP1。本项目通过BAC文库筛选与BAC测序，以已经明确该新型玉米生长素调节蛋白编码基因ZmAuxRP1的基因组结构变异基础。以已经获得的含有ZmAuxRP1基因RNAi干扰、功能互补和过表达等载体转基因玉米群体以及抗感近等基因系为材料，详细分析并明确ZmAuxRP1表达与玉米根生长发育正相关，而与玉米抗病反应负相关。并确定该基因编码蛋白的亚细胞定位于叶绿体。与其叶绿体亚细胞定位结果相一致的是，该蛋白通过调控生长素与次生代谢物的生物合成而影响玉米根生长与抗病反应。相关的代谢途径和生长素运输等抑制剂处理各种转基因玉米和抗感近等基因系，也能验证其对玉米生长发育和抗病性状的作用；同时对高代纯合的各种转基因玉米和接种后的抗感近等基因系进行转录组测序和代谢组测定，鉴定了其中一些关键代谢物以及IAA含量变化与ZmAuxRP1表达变化直接的相关性。另一方面，构建了ZmAuxRP1和拟南芥同源基因与GFP融合的过表达载体，分析了所获得转基因拟南芥植株不同组织中编码蛋白的亚细胞定位以及各种组织中GUS活性以及生长发育性状变化。结合上述实验结果，揭示了该新型的、功能完全未知基因，ZmAuxRP1，通过在玉米茎腐病抗病中的作用机理及其在玉米生长发育过程中的生物学功能。