水稻磷转运蛋白OsPT8参与低磷调控根系生长的机制研究

OsPT8 played very important roles in Pi uptake and translaction at each stage of rice development.Functional analysis of a phosphate transporter gene OsPT8 in rice will provide theoretical and material foundation for breeding new rice varieties with ideal-plant architecture and efficient phosphorus utilization. Previous research results indicated that OsPT8 played very important roles in Pi uptake and translaction at each stage of rice development. Notably, OsPT8 was also found to be involved in regulation of root growth in low Pi in rice. In an attempt to get a better understanding of the OsPT8's funtion in regulation of root growth under Pi starvation , we tried to further analysis the phenotype of OsPT8-Oe transgene lines in high Pi and low Pi from cellular level at first. Secondly, analysis the expression of OsPT8 under different exogenous hormone ;At last, Free IAA in various organs of the transgenic and WT plants was quantified by high-performance liquid chromatography (HPLC) and visualized by pDR5::GUS. Preliminary study on the regulation of pattern of OsPT8, expression of auxin transporter, content of auxin. All these results will clarify the regulation mechanism of OsPT8 involved in root growth under phosphate stravtion in rice.

高亲和磷转运蛋白OsPT8是水稻在低磷条件下吸收和转运磷酸盐的关键基因，深入研究水稻OsPT8基因的功能对提高水稻的磷肥利用率具有重要意义。我们前期研究已证实OsPT8参与调控水稻体内磷元素的动态平衡，并且影响水稻根系构型的变化。目前关于OsPT8如何参与低磷调控水稻根系生长的机制仍不清楚。因此，本项目以OsPT8转基因突变体为试材，首先从植株和细胞水平研究OsPT8转基因根系对外源激素的响应；其次，利用pOsPT8::GUS转基因水稻研究OsPT8表达模式与生长素信号的关系；同时利用pDR5::GUS转化OsPT8转基因材料的二次转基因水稻染色观察法，结合生长素的HPLC直接测定法研究OsPT8表达模式与生长素分布的关系；最后，从转录水平上研究OsPT8对生长素极性运输相关基因的调控作用。从而阐明OsPT8与生长素在低磷调控根系生长中的相互关系，揭示OsPT8参与低磷调控根系生长的机制。

高亲和磷转运蛋白OsPT8是水稻在低磷条件下吸收和转运磷酸盐的关键基因。前期研究已证实OsPT8参与调控水稻体内磷元素的动态平衡，并且影响水稻根系构型的变化。为了进一步明确OsPT8参与低磷调控水稻根系生长的作用机制，本项目以OsPT8转基因突变体为试材，首先研究OsPT8转基因根系对外源激素和缺磷信号的响应，明确了OsPT8-Oe在正常供磷条件下失去了对外源生长素和缺磷信号的敏感性；其次，利用pOsPT8::GUS转基因水稻研究OsPT8表达模式与生长素信号的关系，明确了OsPT8受缺磷信号和生长素信号诱导增强表达；同时利用pDR5::GUS转化OsPT8转基因材料的二次转基因水稻染色观察法，结合生长素含量的测定，明确了OsPT8-Oe根系构型的改变主要是由根系不同区域生长素的含量发生改变导致的；最后，从转录水平上研究OsPT8对生长素极性运输相关基因的调控作用，明确了OsPT8-Oe转基因株系根系生长素的变化主要是由于生长素的极性运输发生改变导致的。此研究阐明OsPT8在低磷调控根系生长中的功能，OsPT8也是植物中第一个阐明的通过生长素参与调控根系发育的磷转运蛋白，为今后的磷营养高效利用研究提供了新的思路。