紫花苜蓿是全球最重要的豆科牧草，干旱是其减产的重要原因。前期研究发现紫花苜蓿基因MsDIUP1（Drought Induced Unknown Protein 1），转录受干旱和ABA显著诱导、功能未知、启动子序列富含干旱响应元件，并且过表达该基因可提高拟南芥的耐旱性，但其详细机理尚不清楚。在此基础上，本研究拟通过过表达和RNAi干扰将MsDIUP1转入紫花苜蓿，利用激光共聚焦技术和GUS染色方法研究该蛋白的定位和表达、Realtime-PCR比较该基因对干旱和ABA的响应、异源过表达研究其功能保守性、酵母双杂交结合转录组测序挖掘下游基因，同时观察干旱胁迫下不同转基因紫花苜蓿内源ABA含量、气孔、根瘤以及相关生理指标的变化，从而揭示ABA介导下MsDIUP1参与紫花苜蓿响应干旱的分子机理，为紫花苜蓿耐旱育种提供新的候选基因。

Alfalfa is the most valuable forage legume in the world. Drought is the primary factor for the decrease of alfalfa production. In the previous research, we found the expression of alfalfa MsDIUP1(Drought Induced Unknown Protein 1) was significantly induced by drought or ABA treatment, and the promoter sequence of MsDIUP1 contains lots of drought responsive elements. Additionally, the overexpression of the MsDIUP1 improved the drought tolerance of Arabidopsis. However, the detailed mechanism of MsDIUP1 is unclear. Here, we plan to transfer the vectors of 35S:MsDIUP1 and RNAi-MsDIUP1 into alfalfa. To understand the cellular localization and the tissue expression of MsDIUP1, laser confocal microscopy and GUS staining will be used. And the expression of MsDIUP1 in response to drought and ABA will be elaboratively compared by Realtime-PCR. Furthermore, the function conservation of MsDIUP1 will be identified by the heterologous overexpression of MsDIUP1in Arabidopsis. The downstream genes of MsDIUP1 will be mined by the yeast two hybrid system and the transcriptome sequencing, and the changes of endogenous ABA content, stomata, nodule, and related plant physiological indexes in different transgenic alfalfa under drought stress will be surveyed. Together, the molecular mechanism of ABA-mediated MsDIUP1 in alfalfa drought response would be revealed. We believe that this study would contribute a candidate gene for the alfalfa drought tolerance improvement.