Molecular mechanisms regulating Pi-signaling and Pi homeostasis under OsPHR2, a central Pi-signaling regulator, in rice

Abstract

Phosphorus (P) is one of the most important major mineral elements for plant growth and metabolism. Plants have evolved adaptive regulatory mechanisms to maintain phosphate (Pi) homeostasis by improving phosphorus uptake, translocation, remobilization and efficiency of use. Here we review recent advances in our understanding of the OsPHR2-mediated phosphate-signaling pathway in rice. OsPHR2 positively regulates the low-affinity Pi transporter BoldItalicthrough physical interaction and reciprocal regulation of OsPHO2 in roots. OsPT2 is responsible for most of the OsPHR2-mediated accumulation of excess Pi in shoots. OsSPX1 acts as a repressor in the OsPHR2-mediated phosphate-signaling pathway. Some mutants screened from ethyl methanesulfonate (EMS)–mutagenized M2 population of BoldItalic overexpression transgenic line removed the growth inhibition, indicating that some unknown factors are crucial for Pi utilization or plant growth under the regulation of OsPHR2.

Key words： Oryza sativa L.; OsPHR2; OsPT2; OsSPX1; Pi homeostasis

Acknowledgements

Work on Pi signaling and Pi homeostasis in plants is funded by the National Basic Research and Development Program of China (No. 2005CB120900), the Special Program of Rice Functional Genomics of China (No. 2006AA10A102), and the Science and Technology Department of Zhejiang Province, China.

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