Purple acid phosphatase 10c modifies the rice rhizobacterial community and its phosphorus cycling potential

Background and aimesPlant roots secrete acid phosphatases (ACPs) to mineralize rhizosphere organic phosphorus (Po) for absorption. However, the ecological effects of such exudates on the rhizobacterial community and function remain unclear.MethodsPurple acid phosphatase 10c (OsPAP10c) is the major root-secreted ACP under both Pi-sufficient and Pi-deficient conditions in rice. To study the effect of root-secreted ACP on rhizosphere phosphorus (P) cycling and succession of the bacterial community, the previously reported OsPAP10c mutant and overexpression lines were planted in paddy soils with or without P fertilizer (+ P or -P).ResultsThe results showed that the expression of OsPAP10c significantly influenced ACP activity in rhizosphere soil, which changed the bacterial composition by 6.72% to 9.54%. The expression of OsPAP10c helped to recruit P-solubilizing bacteria (PSB) at the filling stage under -P conditions. However, OsPAP10c increased bacterial P competition potentials and rhizosphere alkaline phosphatase (ALP) at the elongation and filling stages under + P conditions. Interestingly, overexpression of OsPAP10c relaxed bacterial P demand pressure and increased the relative abundance of bacteria with nitrogen, sulphur, and iron potential functions, which benefited rice nutrient uptake and growth at the early stages.ConclusionIn conclusion, this study indicated that P fertilizer and root-secreted ACPs cooperatively regulate rhizosphere P cycling potential by modifying the rhizobacterial composition.