豆科植物和根瘤菌形成的共生固氮体系是植物高效获取氮素最经济环保的途径，同时宿主植物为根瘤菌提供生命活动所必须的能源和碳源。因此，协助植物中碳代谢产物转运至根瘤对维持共生固氮体系以及固氮酶活性具有重要意义。本项目拟以研究百脉根根瘤中特异表达的编码多元醇转运蛋白的LjPLT基因功能为切入点，探讨多元醇转运蛋白在根瘤形成与发育中的作用机制。研究内容包括（1）三个在根瘤中特异表达的LjPLT基因的基本分子生物学特性。（2）这三个基因影响百脉根根瘤固氮的机理。该研究将阐明百脉根多元醇转运蛋白的生理生化功能，揭示多元醇转运蛋白影响共生固氮体系的机理；帮助研究者深入了解根瘤的固氮分子机制；为提高豆科植物根瘤的固氮酶活性及培育高固氮效率的植物品种奠定基础。

Legume-Rhizobia symbiotic cooperation is a biochemical processes which consume massive energy, and carbon resource in symbiotic nitrogen fixation is mainly from the carbohydrate in host carbon metabolism. Therefore, the transport of the carbohydrate from host to bacterial could be vital to maintain the nodule nitrogenase activity. Here, the function of three LjPLT genes encoding polyol transporter which high or specifically express in nodules will be investigated. It contains: (1) the physiological and biochemical characteristic of these three genes. (2) the effect of these three genes on nodule organogenesis and development. The results we are going to get will help us to illuminate the function of polyol transporters in Lotus japonicas and also reveal the mechanisms of polyols in nodulation. In additional, the results would help researches to further understand the molecular mechanism of nodule nitrogen fixing and provide a sound theoretical basis for improving symbiotic efficiency of nitrogen-fixing rhizobia and host plants.