A Phosphate‐Starvation Enhanced Purple Acid Phosphatase, GmPAP23 Mediates Intracellular Phosphorus Recycling and Yield in Soybean

ABSTRACT Plant internal phosphorus (P) recycling is a complex process, which is vital for improving plant P use efficiency. However, the mechanisms underlying phosphate (Pi) release from internal organic‐P form remains to be deciphered in crops. Here, we functionally characterised a Pi‐starvation responsive purple acid phosphatase ( PAP ), GmPAP23 in soybean ( Glycine max ). GmPAP23 could hydrolyse a series of Pi‐containing compounds in vitro, such as trehalose‐6‐phosphate and glucose‐ l ‐phosphate. Moreover, GmPAP23 overexpression led to less P distribution in soybean source organs, including mature leaves and pod shells, but more P distribution in seeds under P sufficient conditions, although no effect was observed for transgenic soybean lines with its suppression. Metabolomic analysis found that a group of P‐containing metabolites exhibited differential accumulations in mature leaves between wild type (WT) and GmPAP23 overexpression lines, such as glucose‐ l ‐phosphate and trehalose‐6‐phosphate. Moreover, a MYB transcription factor, GmPHR14 was subsequently found to activate the transcription of GmPAP23 via directly binding to its promoter. Collectively, these findings could highlight that the GmPHR14‐GmPAP23 pathway, which controls internal P recycling in soybean, and thus affect yield.