Zheng Rong, Wang Jugang, Liu Min, Duan Guozhen, Gao Xiaomin, Bai Shulan, Han Yachao
College of Forestry, Inner Mongolia Agricultural University, Hohhot, 010019, Inner Mongolia, China.
College of Life Science and Technology, Inner Mongolia Normal University, Hohhot, 010020, Inner Mongolia, China.
Mycorrhiza. 2016 Oct;26(7):633-44. doi: 10.1007/s00572-016-0702-7. Epub 2016 Apr 21.
Inorganic phosphorus (Pi) is essential for plant growth, and phosphate (P) deficiency is a primary limiting factor in Pinus tabulaeformis development in northern China. P acquisition in mycorrhizal plants is highly dependent on the activities of phosphate transporters of their root-associated fungi. In the current study, two phosphate transporter genes, RlPT and LbPT, were isolated from Rhizopogon luteolus and Leucocortinarius bulbiger, respectively, two ectomycorrhizal fungi forming symbiotic interactions with the P. tabulaeformis. Phylogenetic analysis suggested that the sequence of the phosphate transporter of L. bulbiger is most closely related to a phosphate transporter of Hebeloma cylindrosporum, whereas the phosphate transporter of R. luteolus is most closely related to that of Piloderma croceum. The subcellular localization indicated that RlPT and LbPT were expressed in the plasma membrane. The complementation assay in yeast indicated that both RlPT and LbPT partially compensated for the absence of phosphate transporter activity in the MB192 yeast strain, with a K m value of 57.90 μmol/L Pi for RlPT and 35.87 μmol/L Pi for LbPT. qPCR analysis revealed that RlPT and LbPT were significantly up-regulated at lower P availability, which may enhance P uptake and transport under Pi starvation. Our results suggest that RlPT and LbPT presumably play a key role in Pi acquisition by P. tabulaeformis via ectomycorrhizal fungi.
无机磷（Pi）对植物生长至关重要，而磷（P）缺乏是中国北方油松发育的主要限制因素。菌根植物对磷的获取高度依赖于其根际真菌的磷酸盐转运蛋白的活性。在本研究中，分别从黄须腹菌和黄白乳牛肝菌中分离出两个磷酸盐转运蛋白基因RlPT和LbPT，这两种外生菌根真菌与油松形成共生关系。系统发育分析表明，黄白乳牛肝菌的磷酸盐转运蛋白序列与柱状环柄菇的磷酸盐转运蛋白关系最为密切，而黄须腹菌的磷酸盐转运蛋白与黄褐皮伞的关系最为密切。亚细胞定位表明RlPT和LbPT在质膜中表达。酵母中的互补试验表明，RlPT和LbPT都部分补偿了MB192酵母菌株中磷酸盐转运蛋白活性的缺失，RlPT的Km值为57.90 μmol/L Pi，LbPT的Km值为35.87 μmol/L Pi。qPCR分析显示，在较低的磷有效性下，RlPT和LbPT显著上调，这可能会在磷饥饿条件下增强磷的吸收和运输。我们的结果表明，RlPT和LbPT可能在油松通过外生菌根真菌获取磷的过程中起关键作用。
