The ACID PHOSPHATASE 1 regulates Pi stress adaptation by maintaining intracellular Pi homeostasis

Abstract

The concentration and homeostasis of intracellular phosphate (Pi) are crucial for sustaining cell metabolism and growth. During short-term Pi starvation, intracellular Pi is maintained relatively constant at the expense of vacuolar Pi. After the vacuolar stored Pi is exhausted, the plant cells induce the synthesis of intracellular acid phosphatase (APase) to recycle Pi from expendable organic phosphate (Po). In this study, the expression, enzymatic activity and subcellular localization of ACID PHOSPHATASE 1 (OsACP1) were determined. OsACP1 expression is specifically induced in almost all cell types of leaves and roots under Pi stress conditions. OsACP1 encodes an acid phosphatase with broad Po substrates and localizes in the endoplasmic reticulum (ER) and Golgi apparatus (GA). Phylogenic analysis demonstrates that OsACP1 has a similar structure with human acid phosphatase PHOSPHO1. Overexpression or mutation of OsACP1 affected Po degradation and utilization, which further influenced plant growth and productivity under both Pi-sufficient and Pi-deficient conditions. Moreover, overexpression of OsACP1 significantly affected intracellular Pi homeostasis and Pi starvation signalling. We concluded that OsACP1 is an active acid phosphatase that regulates rice growth under Pi stress conditions by recycling Pi from Po in the ER and GA.

Genome wide association studies for acid phosphatase activity at varying phosphorous levels in Brassica juncea L

“…Overexpression of PAP10 (that shows both SAP and IAP properties) in Arabidopsis and rice have been found to significantly increase the plant's ability to degrade Po and tolerance to low Pi stress (Wang et al, 2011;Deng et al, 2020). PNP and AT5G51260 regulate Pi tolerance by releasing Pi during polynucleotide synthesis from nucleotide diphosphates or triphosphates (Marchive et al, 2010;Deng et al, 2021). We also predicted several genes with roles in phytohormone and sugar signalling pathways and root modulation.…”

Identification of vacuolar phosphate influx transporters in Brassica napus

“…To adapt to P limitation, plants have evolved several mechanisms to fine‐tune cellular Pi homoeostasis. For example, under Pi‐limited conditions, organic acids and acid phosphatase exuded by plants can improve Pi availability (Deng et al, 2022; Joan et al, 2017; Wang et al, 2018; Yang et al, 2019; 2021). In addition, the core transcription factor PHOSPHATE STARVATION RESPONSE 1 (PHR1) is activated rapidly to up‐regulate PHOSPHATE TRANSPORTER 1 (PHT1) genes encoding high‐affinity Pi transporters (Chiou & Lin, 2011).…”

“…To adapt to P limitation, plants have evolved several mechanisms to fine-tune cellular Pi homoeostasis. For example, under Pi-limited conditions, organic acids and acid phosphatase exuded by plants can improve Pi availability (Deng et al, 2022;Joan et al, 2017;Wang et al, 2018;Yang et al, 2019;.…”