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.

Keywords

Oryza sativa L. / OsPHR2 / OsPT2 / OsSPX1 / Pi homeostasis

References

[1] Ai P, Sun S, Zhao J, Fan X, Xin W, Guo Q, Yu L, Shen Q, Wu P, Miller A J, Xu G (2009). Two rice phosphate transporters, OsPht1;2 and OsPht1;6, have different functions and kinetic properties in uptake and translocation. Plant J, 57(5): 798-809

[2] Aung K, Lin S I, Wu C C, Huang Y T, Su C L, Chiou T J (2006). pho2, a phosphate overaccumulator, is caused by a nonsense mutation in a microRNA399 target gene. Plant Physiol, 141(3): 1000-1011

[3] Barabote R D, Tamang D G, Abeywardena S N, Fallah N S, Fu J Y, Lio J K, Mirhosseini P, Pezeshk R, Podell S, Salampessy M L, Thever M D, Saier M H Jr (2006). Extra domains in secondary transport carriers and channel proteins. Biochim Biophys Acta, 1758(10): 1557-1579

[4] Bari R, Datt Pant B, Stitt M, Scheible W R (2006). PHO2, microRNA399, and PHR1 define a phosphate-signaling pathway in plants. Plant Physiol, 141(3): 988-999

[5] Chen Y F, Li L Q, Xu Q, Kong Y H, Wang H, Wu W H (2009). The WRKY6 transcription factor modulates PHOSPHATE1 expression in response to low Pi stress in Arabidopsis. Plant Cell, 21(11): 3554-3566

[6] Chen Z H, Nimmo G A, Jenkins G I, Nimmo H G (2007). BHLH32 modulates several biochemical and morphological processes that respond to Pi starvation in Arabidopsis. Biochem J, 405(1): 191-198

[7] Chiou T J, Aung K, Lin S I, Wu C C, Chiang S F, Su C L (2006). Regulation of phosphate homeostasis by MicroRNA in Arabidopsis. Plant Cell, 18(2): 412-421

[8] Devaiah B N, Karthikeyan A S, Raghothama K G (2007a). WRKY75 transcription factor is a modulator of phosphate acquisition and root development in Arabidopsis. Plant Physiol, 143(4): 1789-1801

[9] Devaiah B N, Madhuvanthi R, Karthikeyan A S, Raghothama K G (2009). Phosphate starvation responses and gibberellic acid biosynthesis are regulated by the MYB62 transcription factor in Arabidopsis. Mol Plant, 2(1): 43-58

[10] Devaiah B N, Nagarajan V K, Raghothama K G (2007b). Phosphate homeostasis and root development in Arabidopsis are synchronized by the zinc finger transcription factor ZAT6. Plant Physiol, 145(1): 147-159

[11] Duan K, Yi K, Dang L, Huang H, Wu W, Wu P (2008). Characterization of a sub-family of Arabidopsis genes with the SPX domain reveals their diverse functions in plant tolerance to phosphorus starvation. Plant J, 54(6): 965-975

[12] Fujii H, Chiou T J, Lin S I, Aung K, Zhu J K (2005). A miRNA involved in phosphate-starvation response in Arabidopsis. Curr Biol, 15(22): 2038-2043

[13] Hamburger D, Rezzonico E, MacDonald-Comber Petétot J, Somerville C, Poirier Y (2002). Identification and characterization of the Arabidopsis PHO1 gene involved in phosphate loading to the xylem. Plant Cell, 14(4): 889-902

[14] Kang X, Ni M (2006). Arabidopsis SHORT HYPOCOTYL UNDER BLUE1 contains SPX and EXS domains and acts in cryptochrome signaling. Plant Cell, 18(4): 921-934

[15] Liu F, Wang Z Y, Ren H Y, Shen C J, Li Y, Ling H Q, Wu C Y, Lian X M, Wu P (2010). OsSPX1 suppresses the function of OsPHR2 in the regulation of expression of OsPT2 and phosphate homeostasis in shoots of rice. Plant J, 62(3): 508-517

[16] Nakanishi H, Okumura N, Umehara Y, Nishizawa N K, Chino M, Mori S (1993). Expression of a gene specific for iron deficiency (Ids3) in the roots of Hordeum vulgare. Plant Cell Physiol, 34(3): 401-410

[17] Poirier Y, Thoma S, Somerville C, Schiefelbein J (1991). Mutant of Arabidopsis deficient in xylem loading of phosphate. Plant Physiol, 97(3): 1087-1093

[18] Rubio V, Linhares F, Solano R, Martín A C, Iglesias J, Leyva A, Paz-Ares J (2001). A conserved MYB transcription factor involved in phosphate starvation signaling both in vascular plants and in unicellular algae. Genes Dev, 15(16): 2122-2133

[19] Sell S, Hehl R (2005). A fifth member of the tomato 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase gene family harbours a leucine zipper and is anaerobically induced. DNA Seq, 16(1): 80-82

[20] Wang C, Ying S, Huang H, Li K, Wu P, Shou H (2009a). Involvement of OsSPX1 in phosphate homeostasis in rice. Plant J, 57(5): 895-904

[21] Wang Y, Ribot C, Rezzonico E, Poirier Y (2004). Structure and expression profile of the Arabidopsis PHO1 gene family indicates a broad role in inorganic phosphate homeostasis. Plant Physiol, 135(1): 400-411

[22] Wang Z, Hu H, Huang H, Duan K, Wu Z, Wu P (2009b). Regulation of OsSPX1 and OsSPX3 on expression of OsSPX domain genes and Pi-starvation signaling in rice. J Integr Plant Biol, 51(7): 663-674

[23] Wu P, Xu J M (2010). Does OsPHR2, central Pi-signaling regulator, regulate some unknown factors crucial for plant growth? Plant Signal Behav, 5(6): 712-714

[24] Yi K, Wu Z, Zhou J, Du L, Guo L, Wu Y, Wu P (2005). OsPTF1, a novel transcription factor involved in tolerance to phosphate starvation in rice. Plant Physiol, 138(4): 2087-2096

[25] Zhou J, Jiao F, Wu Z, Li Y, Wang X, He X, Zhong W, Wu P (2008). OsPHR2 is involved in phosphate-starvation signaling and excessive phosphate accumulation in shoots of plants. Plant Physiol, 146(4): 1673-1686

[26] Zhou Y, Ni M (2009). SHB1 plays dual roles in photoperiodic and autonomous flowering. Dev Biol, 331(1): 50-57

[27] Zhou Y, Ni M (2010). SHORT HYPOCOTYL UNDER BLUE1 truncations and mutations alter its association with a signaling protein complex in Arabidopsis. Plant Cell, 22(3): 703-715

[28] Zhou Y, Zhao X Y, Kang X, Zhang X S, Ni M (2009). SHORT HYPOCOTYL UNDER BLUE1 associates with MINISEED3 and HAIKU2 promoters in vivo to regulate Arabidopsis seed development. Plant Cell, 21(1): 106-117

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.

RIGHTS & PERMISSIONS

2014 Higher Education Press and Springer-Verlag Berlin Heidelberg