State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, People's Republic of China.
Plant Physiol. 2012 May;159(1):169-83. doi: 10.1104/pp.112.194217. Epub 2012 Mar 6.
An R2R3 MYB transcription factor, OsMYB2P-1, was identified from microarray data by monitoring the expression profile of rice (Oryza sativa ssp. japonica) seedlings exposed to phosphate (Pi)-deficient medium. Expression of OsMYB2P-1 was induced by Pi starvation. OsMYB2P-1 was localized in the nuclei and exhibited transcriptional activation activity. Overexpression of OsMYB2P-1 in Arabidopsis (Arabidopsis thaliana) and rice enhanced tolerance to Pi starvation, while suppression of OsMYB2P-1 by RNA interference in rice rendered the transgenic rice more sensitive to Pi deficiency. Furthermore, primary roots of OsMYB2P-1-overexpressing plants were shorter than those in wild-type plants under Pi-sufficient conditions, while primary roots and adventitious roots of OsMYB2P-1-overexpressing plants were longer than those of wild-type plants under Pi-deficient conditions. These results suggest that OsMYB2P-1 may also be associated with the regulation of root system architecture. Overexpression of OsMYB2P-1 led to greater expression of Pi-responsive genes such as Oryza sativa UDP-sulfoquinovose synthase, OsIPS1, OsPAP10, OsmiR399a, and OsmiR399j. In contrast, overexpression of OsMYB2P-1 suppressed the expression of OsPHO2 under both Pi-sufficient and Pi-deficient conditions. Moreover, expression of OsPT2, which encodes a low-affinity Pi transporter, was up-regulated in OsMYB2P-1-overexpressing plants under Pi-sufficient conditions, whereas expression of the high-affinity Pi transporters OsPT6, OsPT8, and OsPT10 was up-regulated by overexpression of OsMYB2P-1 under Pi-deficient conditions, suggesting that OsMYB2P-1 may act as a Pi-dependent regulator in controlling the expression of Pi transporters. These findings demonstrate that OsMYB2P-1 is a novel R2R3 MYB transcriptional factor associated with Pi starvation signaling in rice.
一个 R2R3 MYB 转录因子，OsMYB2P-1，是通过监测水稻（Oryza sativa ssp. japonica）幼苗在缺磷（Pi）培养基中表达谱的微阵列数据鉴定出来的。OsMYB2P-1 的表达受 Pi 饥饿诱导。OsMYB2P-1 定位于细胞核，并表现出转录激活活性。在拟南芥（Arabidopsis thaliana）和水稻中过表达 OsMYB2P-1 增强了对 Pi 饥饿的耐受性，而在水稻中通过 RNA 干扰抑制 OsMYB2P-1 使转基因水稻对 Pi 缺乏更敏感。此外，在 Pi 充足条件下，OsMYB2P-1 过表达植物的主根比野生型植物的主根短，而在 Pi 缺乏条件下，OsMYB2P-1 过表达植物的主根和不定根比野生型植物的主根和不定根长。这些结果表明，OsMYB2P-1 可能也与根系结构的调节有关。OsMYB2P-1 的过表达导致 Pi 反应基因如 UDP-半乳糖硫酸酯合酶、OsIPS1、OsPAP10、OsmiR399a 和 OsmiR399j 的表达增加。相反，在 Pi 充足和缺乏条件下，OsMYB2P-1 的过表达均抑制 OsPHO2 的表达。此外，在 Pi 充足条件下，OsPT2（编码低亲和力 Pi 转运体）的表达在 OsMYB2P-1 过表达植物中上调，而在 Pi 缺乏条件下，高亲和力 Pi 转运体 OsPT6、OsPT8 和 OsPT10 的表达被 OsMYB2P-1 的过表达上调，表明 OsMYB2P-1 可能作为一种 Pi 依赖性调节剂在控制 Pi 转运体的表达中发挥作用。这些发现表明，OsMYB2P-1 是一种与水稻 Pi 饥饿信号转导相关的新型 R2R3 MYB 转录因子。
