School of Bioscience and Biotechnology, Tokyo University of Technology, 1404-1 Katakura, Hachioji, Tokyo 192-0982, Japan.
School of Bioscience and Biotechnology, Tokyo University of Technology, 1404-1 Katakura, Hachioji, Tokyo 192-0982, Japan.
Plant Sci. 2023 Feb;327:111540. doi: 10.1016/j.plantsci.2022.111540. Epub 2022 Nov 19.
Although attempts to improve the phosphate (Pi) uptake and use efficiency by constitutively overexpressing phosphate transporters have resulted in enhanced Pi or total phosphorous contents, growth promotion by Pi acquisition was observed in only a few cases. This study examined the effect of the tissue-specific overexpression of phosphate transporter on Pi acquisition and plant growth. We cloned cDNA for a wheat phosphate transporter, TaPT2, using PCR and confirmed its Pi transport activity in Arabidopsis suspension cells. The overexpression of TaPT2 by the Arabidopsis Shaker family inward rectifying potassium channel 1 (AKT1) promoter, dominantly expressed in root epidermal cells, resulted in increased root and shoot growth of transgenic Arabidopsis under Pi-replete and Pi-depleted conditions. However, their Pi and total P contents did not increase. The overexpression of TaPT2 by the constitutive promoter, actin8 (ACT8), increased shoot total P contents in transgenic plants, but did not promote their growth. These results suggested that enhanced Pi uptake in root epidermal cells is suitable as a driving force for Pi transport from roots to shoots, improving subsequent Pi use in shoots. Thus, the root epidermal cell-specific expression of TaPT2 may be a simple and promising strategy for enhancing plant Pi uptake and efficiency.
尽管通过组成型过表达磷酸盐转运体来提高磷酸盐（Pi）的吸收和利用效率，导致 Pi 或总磷含量增加，但仅在少数情况下观察到通过 Pi 摄取促进生长。本研究探讨了组织特异性过表达磷酸盐转运体对 Pi 吸收和植物生长的影响。我们使用 PCR 克隆了小麦磷酸盐转运体 TaPT2 的 cDNA，并在拟南芥悬浮细胞中证实了其 Pi 转运活性。TaPT2 通过拟南芥 Shaker 家族内向整流钾通道 1（AKT1）启动子的过表达，在根表皮细胞中优势表达，导致转基因拟南芥在 Pi 充足和 Pi 缺乏条件下根和地上部分的生长增加。然而，它们的 Pi 和总 P 含量并没有增加。TaPT2 通过组成型启动子 actin8（ACT8）的过表达增加了转基因植物地上部分的总 P 含量，但没有促进其生长。这些结果表明，增强根表皮细胞中的 Pi 吸收适合作为 Pi 从根部运输到地上部分的驱动力，从而提高地上部分的 Pi 利用效率。因此，TaPT2 在根表皮细胞中的特异性表达可能是增强植物 Pi 吸收和利用效率的一种简单而有前途的策略。
