Purple Acid Phosphatases (PAPs): Molecular Regulation and Diverse Physiological Roles in Plants

Abstract

Purple acid phosphatases (PAPs) represent the largest group of acid phosphatases (APases) that hydrolyze phosphorus from phosphate monoesters/anhydrides. PAPs exist as a multigene family in nearly all plant species and have been widely characterized for their roles in tolerance to phosphate (Pi) deficiency. PAPs are majorly involved in Pi uptake and recycling, thus influencing Pi acquisition and utilization efficiency of plants. Posttranscriptional and posttranslational regulation of PAPs is a complex phenomenon involving several key regulators. Though most of the PAPs are low Pi inducible, Pi deficiency is not found to affect the expression of few PAPs. Functional analysis of these PAPs uncovered their diverse functional roles. Apart from low Pi tolerance, several studies indicate broad functions of PAPs in the regulation of seed traits, root development, osmotic, oxidative, and salt stress tolerance. This chapter provides more in-depth understanding and insights into the broader physiological functions of PAPs in plants and their molecular regulation and finally, discusses their possible deployment in crop improvement.