利用生物信息学技术、RNA-Seq转录组测序方法获得了8 个干旱胁迫显著差异表达的玉米MAPKKK 基因。对11个玉米自交系进一步RT-PCR分析表明，ZmMKKK18基因表达水平差异极显著，且与植株生物量的耐旱系数呈显著相关。利用玉米自然变异群体对ZmMKKK18基因的遗传变异和苗期耐旱性表型的关联分析发现，该基因的遗传变异和苗期耐旱性显著关联。本研究拟通过分析ZmMKKK18基因的玉米干旱响应的精细表达模式、开展该基因在玉米中的过表达及基因敲除研究，以及通过关联分析与连锁分析方法分析ZmMKKK18基因与植株耐旱性的关系，鉴定ZmMKKK18基因在干旱胁迫逆境下的的生物学功能；同时通过转录调控分析以及干旱应答调控的互作蛋白鉴定分析等方法，明晰玉米ZmMKKK18基因响应干旱胁迫的作用机理。

In this study, eight MAPKKK genes have been identified to show a significant differences of the expression level responsive to drought stress in maize using the in silico analysis and RNA-Seq technology. Further qRT-PCR analysis in 11 maize inbred lines indicated, among 8 genes, ZmMKKK18 showed the significantly up-regulated trend in response to drought stress. Correlation analysis revealed that there was a significant correlation between expression levels of ZmMKKK18 and relative biomass responsive to drought. Association analysis between genetic variation of ZmMKKK18 gene and plants drought tolerance at seedling stage in a natural variation maize population showed that the genetic variation of ZmMKKK18 was significantly associated with drought tolerance of plants. In this study, we will analyze the biological function with respect to drought tolerance of target gene through the expression pattern analysis of ZmMKKK18 responsive to drought stress, the over-expression of ZmMKKK18 and gene knock-out analysis in maize. The correlation of ZmMKKK18 gene sequence variation with plant drought tolerance will be analyzed in various maize inbred lines to identify the genetic effect of ZmMKKK18 on drought tolerance. Meanwhile, the transcription regulation of ZmMKKK18 and interaction protein analysis responsive to drought stress will be studied to investigate the mechanism of drought stress tolerance of ZmMKKK18 gene.