Root secretory purple acid phosphatase is involved in the utilization of phosphorus from organic fertilizer in rice

Abstract Background and aims Organic fertilizer (OF) is beneficial for crop yield and quality, however, most phosphorus in OF are in organic forms, and cannot be utilized until they are hydrolyzed to inorganic phosphate (Pi). Although root-secreted acid phosphatases (APases) play an important role in hydrolyzing organic phosphorus (Po), it is unclear whether they improve the utilization efficiency of OF, and whether purple acid phosphatase (PAP) genes function in plants’ utilization of OF. Methods We report on a 10-year field study of OF application to rice, and the response of rice root-secreted APase activity to organic fertilization. Wild type (WT), OsPAP10c overexpressing, and OsPAP10c deficient rice were used to evaluate the role of this gene on the regulation of root-secreted APase activity in response OF and its subsequent utilization. Results Over 10 years of OF application, the APase activity of rice root secretions increased, over rice that had been fertilized with chemical fertilizer (CF). The APase activity in the rhizosphere soil of OF treated rice increased as well compared to CF treated rice. In PAP10c-OE rice, APase activity in the root secretions was greater than in WT rice, the activity in pap10c rice was less than in WT in OF treatment. Conclusion OF application enhances the APase activity of rice root secretions and improves the APase activity in the rhizosphere soil, which facilitates the hydrolysis of Po in OF. This hydrolysis generated sufficient available Pi for rice growth and production. OsPAP10c positively regulates root-secreted APase activity and Po utilization efficiency in rice in OF treated fields.