Two rice phosphate transporters, OsPht1;2 and OsPht1;6, have different functions and kinetic properties in uptake and translocation
Two rice phosphate transporters, OsPht1;2 and OsPht1;6, have different functions and kinetic properties in uptake and translocation
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两种水稻磷酸盐转运蛋白 OsPht1;2 和 OsPht1;6 在摄取和转运方面具有不同的功能和动力学特性
DOI：
10.1111/j.1365-313x.2008.03726.x
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发表时间：
2009-03-01
期刊：
影响因子：
7.2
通讯作者：
Xu, Guohua
中科院分区：
文献类型：
--
作者：
Ai, Penghui;Sun, Shubin;Xu, Guohua
植物磷酸盐 (Pi) 转运蛋白介导植物内这种养分的吸收和转运。水稻（Oryza sativa）基因组中共有 13 个序列可被鉴定为属于 Pi 转运蛋白（Pht1）家族。在这里，我们报告了该家族两个成员的表达模式、生物学特性和生理作用：OsPht1;2 (OsPT2) 和 OsPht1;6 (OsPT6)。在缺磷条件下，根和芽中这两个基因的表达均显着增加。通过使用在启动子驱动下表达GUS报告基因的转基因水稻植物，我们检测到OsPT2仅定位于初生根和侧根的中柱，而OsPT6在较年轻的初生根和侧根的表皮和皮层细胞中表达。 OsPT6（而非 OsPT2）能够在高亲和力浓度范围内补充酵母 Pi 摄取突变体。当提供 mM 外部浓度时，注射 OsPT2 mRNA 的非洲爪蟾卵母细胞显示 Pi 积累增加，并且 Pi 引起细胞膜电位去极化。两项结果均表明 OsPT2 介导卵母细胞对 Pi 的摄取。在转基因水稻中，通过RNA干扰敲低OsPT2或OsPT6的表达会显着降低Pi从根部到地上部的吸收和长距离运输。总而言之，这些数据表明 OsPT6 在整个植物中的 Pi 吸收和易位中发挥着广泛的作用，而 OsPT2 是一种低亲和力的 Pi 转运蛋白，在植物中储存的 Pi 的易位中发挥作用。
Plant phosphate (Pi) transporters mediate the uptake and translocation of this nutrient within plants. A total of 13 sequences in the rice (Oryza sativa) genome can be identified as belonging to the Pi transporter (Pht1) family. Here, we report on the expression patterns, biological properties and the physiological roles of two members of the family: OsPht1;2 (OsPT2) and OsPht1;6 (OsPT6). Expression of both genes increased significantly under Pi deprivation in roots and shoots. By using transgenic rice plants expressing the GUS reporter gene, driven by their promoters, we detected that OsPT2 was localized exclusively in the stele of primary and lateral roots, whereas OsPT6 was expressed in both epidermal and cortical cells of the younger primary and lateral roots. OsPT6, but not OsPT2, was able to complement a yeast Pi uptake mutant in the high-affinity concentration range. Xenopus oocytes injected with OsPT2 mRNA showed increased Pi accumulation and a Pi-elicited depolarization of the cell membrane electrical potential, when supplied with mM external concentrations. Both results show that OsPT2 mediated the uptake of Pi in oocytes. In transgenic rice, the knock-down of either OsPT2 or OsPT6 expression by RNA interference significantly decreased both the uptake and the long-distance transport of Pi from roots to shoots. Taken together, these data suggest OsPT6 plays a broad role in Pi uptake and translocation throughout the plant, whereas OsPT2 is a low-affinity Pi transporter, and functions in translocation of the stored Pi in the plant.