氨基酸转运蛋白OsATL4在水稻氮素吸收及再分配中的调控作用研究

氨基酸转运蛋白对植物氨基酸吸收、转运和利用具有重要的作用，影响生长发育和产量形成等多个方面。前期研究发现，氨基酸转运基因OsATL4的启动子序列在水稻自然变异品种中有三种主要类型，不同类型转录水平与单株分蘖数和产量存在显著关联。提高基因表达抑制了水稻分蘖数、引起叶片衰老并降低单株产量，而基因敲除则相反。为了探明该基因在氨基酸吸收和再分配中的调控机制，本项目拟：1）通过探究基因的组织表达、亚细胞定位和氨基酸底物等了解其在水稻有机氮适应中的作用；2）通过转基因植株在不同氮源水培，并对各部位氨基酸和总氮测定、转录组分析等确定其对氮吸收及分蘖芽生长的影响；3）通过氨基酸和总氮动态测定、组织形态观察和转录组等确定基因对水稻氮素再分配和叶片衰老与种子产量的调控作用。本项目旨在揭示OsATL4基因在氨基酸营养吸收与利用上的调控作用，为水稻分蘖和产量的形成提供理论和实践基础。

Amino acid transporters play an important role in the absorption, transport and utilization of amino acids in plants, affecting plant growth, development and yield formation. In this study, we found that the promoter sequences of the amino acid transporter gene OsATL4 had three types in natural variation of rice, and there was a correlation between transcription expression levels in these Haps with tiller number and grain yield. Over-expression of OsATL4 resulted in decreasing of tiller number and grain yield, promoting of leaf senescence, whereas knock-out of OsATL4 exhibited the opposite result. In order to find out the regulatory mechanism of the gene in amino acid absorption and reallocation, firstly, gene expression in tissues, subcellular localization and amino acid specific substrate transport will be performed for understanding the role of gene in rice organic nitrogen adaptation. Secondly, the growth of rice transgenic plants under different nitrogen treatments, amino acid concentration, total nitrogen and RNA-seq will be measured for effection of nitrogen absorption and tiller bud growth. Finally, dynamic amino acid and total nitrogen concentration, morphology observation, and RNA-seq will be determined for nitrogen reallocation, leaf senescence and grain yield. This study would be helpful to further understand the regulatory role of OsATL4 in the regulation of amino acid absorption and utilization. Besides, it would also provide valuable theoretical and practical basis for improving rice tillering and grain yield in rice.