Regulation of phosphate starvation-mediated induction and secretion of Arabidopsis purple acid phosphatases AtPAP10 through local and systemic signaling
Dong  Liu

School of Life Sciences, Tsinghua University

Abstract
Induction and secretion of acid phosphatase (APases) is a universal response of plants to phosphate (Pi) starvation. The secreted APases are believed to scavenge Pi from organophosphate compounds in the external environment, thus increase the availability of Pi for root absorption. The molecular mechanism that regulates this adaptive response, however, is largely unknown. Arabidopsis purple acid phosphatase 10 (AtPAP10) is a Pi starvation-induced APase which is predominantly associated with root surface after its secretion and plays an important role in plant adaptation to Pi starvation. Sucrose and ethylene are involved in Pi starvation-mediated induction of AtPAP10 activity. The AtPAP10 APase activity on the root surface is dependent on the external rather than internal Pi concentration. Induction of AtPAP10 activity by Pi starvation is controlled at multiple levels: transcription, translation, and secretion. Using root-split experiments, we demonstrated that transcription of AtPAP10 gene is regulated through systemic signalling whereas translation of AtPAP10 mRNA and secretion of AtPAP10 protein are regulated through local signalling.