Molecular Mechanisms Of Phosphate Starvation Influencing The Growth In Rice Regulated By OsCYCP4;2

Inorganic phosphate(Pi)is one of the essential elements for plant growth.Phosphate plays important roles in the process of plant growth and metabolism.Phosphate starvation leads to a strong reduction in shoot growth and yield of crops.Previous research has demonstrated that the reduced shoot growth is not a direct consequence of low levels of shoot phosphorus,but is caused by extensive gene expression reprogramming triggered by phosphate deficiency.Our recent work has showed that OsCYCP1;1,one of the PHO80 homologs in rice,negatively regulates phosphate starvation signaling in the root.Here,we found out,(1)The proliferation of epidermal cells in rice were suppressed under Pi sufficient by microscope.(2)We found that the transcriptional and translational levels of OsCYCP4;2 were induced by phosphate starvation.(3)Overexpression of the phosphate starvation induced OsCYCP4;2 suppressed the rice growth by reducing cell proliferation.(4)The loss-of-function mutant cycp4;2 displayed lower sensitivity to phosphate starvation induced growth inhibition.(5)The phosphate starvation induced OsCYCP4;2 may involve in phosphate starvation signaling,as the loss-of-function mutants displayed elevated phosphate concentrations under normal condition.Under Pi sufficient the induced expression of PSI genes was enhanced in mutants and inhibited in over-expression plants.Besides,the expression of PSI genes was also inhibited by the over-expression of OsCYCP4;2 under normal condition.OsCYCP4;2 negatively regulated phosphate starvation signaling.Together,our findings demonstrate that phosphate starvation induced OsCYCP4;2 might coordinate phosphate starvation signaling and cell cycle progression under phosphate starvation stress.