浅黄根须腹菌磷酸盐转运蛋白基因异源表达分析

为探究外生菌根真菌对油松磷吸收作用的分子机理,以油松优良乡土外生菌根真菌——浅黄根须腹菌Rhizopogon luteolus的磷酸盐转运蛋白基因（RlPT）为对象,在缺陷酵母MB192中进行了异源表达研究。结果显示,该cDNA编码的蛋白质能够互补高亲和力磷酸盐转运蛋白pho84的功能;由不同pH条件下生长试验可知,该蛋白是一个与质子相偶联的运输蛋白;RlPT测算的K_m值为57.90μmol/L磷酸盐;通过酸性磷酸酶的活性检测,进一步验证该基因是具有高亲和力磷酸盐转运蛋白功能的基因。激光共聚焦显微观察表明,该蛋白在低磷条件下多定位于酵母细胞膜上发挥其功能。

Heterologous expression of a phosphate transporter gene from Rhizopogon luteolus

For a better understanding of the molecular mechanism involved in uptaking orthophosphate (Pi) in Pinus tabulaeformis, cDNA of a putative phosphate transporter gene from Rhizopogon luteolus, an excellent native ectomycorrhizal fungus associated with P. tabulaeformis, was expressed in the yeast mutant strain MB192. The complementation assay in yeast showed that RlPT could compensate the pho84 phosphate transporter activity in yeast. The pH experiment under different growth conditions suggested that RlPT was a proton-coupled protein, and the K_m of RlPT was 57.90µmol/L. The detection results of acid phosphatase enzyme activities indicated that the RlPT encoded a high affinity phosphatase transporter, which was located on plasma membrane of yeast and functioned at low P concentration through the observation of laser scanning confocal microscope.