Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA.
Plant Signal Behav. 2011 Nov;6(11):1676-8. doi: 10.4161/psb.6.11.17906. Epub 2011 Nov 1.
The mobilization of inorganic phosphate (Pi) in planta is a complex process regulated by a number of developmental and environmental cues. Plants possess many Pi transporters that acquire Pi from the rhizosphere and translocate it throughout the plant. A few members of the high-affinity Pht1 family of Pi transporters have been functionally characterized and, for the most part, have been shown to be involved in Pi acquisition. We recently demonstrated that the Arabidopsis Pi transporter, Pht1;5, plays a key role in translocating Pi between tissues. Loss-of-function pht1;5 mutant seedlings accumulated more P in shoots relative to wild type but less in roots. In contrast, overexpression of Pht1;5 resulted in a lower P shoot:root ratio compared with wild type. Also, the rosette leaves of Pht1;5-overexpression plants senesced early and contained less P, whereas reproductive organs accumulated more P than those of wild type. Herein we report the molecular response of disrupting Pht1;5 expression on other factors known to modulate P distribution. The results reveal reciprocal mis-regulation of PHO1, miR399d, and At4 in the pht1;5 mutant and Pht1;5-overexpressor, consistent with the corresponding changes in P distribution in these lines. Together our studies reveal a complex role for Pht1;5 in regulating Pi homeostasis.
植物中无机磷酸盐（Pi）的动员是一个受许多发育和环境线索调节的复杂过程。植物拥有许多 Pi 转运蛋白，可以从根际获取 Pi 并将其转运到整个植物中。一些高亲和力 Pht1 家族 Pi 转运蛋白的成员已被功能表征，并且在大多数情况下，它们被证明参与 Pi 的获取。我们最近证明，拟南芥 Pi 转运蛋白 Pht1;5 在组织间转运 Pi 中发挥关键作用。与野生型相比，功能丧失型 pht1;5 突变体幼苗的地上部分积累了更多的 P，但根部则更少。相比之下，与野生型相比，Pht1;5 的过表达导致较低的 P 地上部分：根比值。此外，Pht1;5 过表达植物的莲座叶提前衰老，含 P 量较少，而生殖器官积累的 P 量多于野生型。在此，我们报告了破坏 Pht1;5 表达对其他已知调节 P 分布的因素的分子反应。结果表明，在 pht1;5 突变体和 Pht1;5 过表达系中，PHO1、miR399d 和 At4 的反向调节不一致，与这些系中 P 分布的相应变化一致。总之，我们的研究揭示了 Pht1;5 在调节 Pi 稳态中的复杂作用。
