Phosphate and phosphite have a differential impact on the proteome and phosphoproteome of Arabidopsis suspension cell cultures. (19th December 2020)

• Record Type: Journal Article
• Authors: Mehta, Devang; Ghahremani, Mina; Pérez‐Fernández, Maria; Tan, Maryalle; Schläpfer, Pascal; Plaxton, William C.; Uhrig, R. Glen
• Is Part Of: Plant journal. Volume 105:Number 4(2021)
• Page Start: 924
• Page End: 941
• Publication Date: 2020-12-19
• Subjects: phosphorus -- phosphite -- quantitative proteomics -- phosphoproteomics -- protein phosphorylation -- phosphate starvation response; Plant molecular biology -- Periodicals; Plant cells and tissues -- Periodicals; Botany -- Periodicals; 580
• DOI: 10.1111/tpj.15078
• Languages: English
• ISSNs: 0960-7412

Abstract

SUMMARY: Phosphorus absorbed in the form of phosphate (H2 PO4 − ) is an essential but limiting macronutrient for plant growth and agricultural productivity. A comprehensive understanding of how plants respond to phosphate starvation is essential for the development of more phosphate‐efficient crops. Here we employed label‐free proteomics and phosphoproteomics to quantify protein‐level responses to 48 h of phosphate versus phosphite (H2 PO3 − ) resupply to phosphate‐deprived Arabidopsis thaliana suspension cells. Phosphite is similarly sensed, taken up and transported by plant cells as phosphate, but cannot be metabolized or used as a nutrient. Phosphite is thus a useful tool for differentiating between non‐specific processes related to phosphate sensing and transport and specific responses to phosphorus nutrition. We found that responses to phosphate versus phosphite resupply occurred mainly at the level of protein phosphorylation, complemented by limited changes in protein abundance, primarily in protein translation, phosphate transport and scavenging, and central metabolism proteins. Altered phosphorylation of proteins involved in core processes such as translation, RNA splicing and kinase signaling was especially important. We also found differential phosphorylation in response to phosphate and phosphite in 69 proteins, including splicing factors, translation factors, the PHT1;4 phosphate transporter and the HAT1 histone acetyltransferase – potential phospho‐switches signaling changes in phosphorus nutrition. Our study illuminates several new aspects of the phosphate starvation response and identifies important targets for further investigation and potential crop improvement. Significance Statement: Here we study the proteome and phosphoproteome of phosphate‐starved Arabidopsis thaliana cells that were re‐fed phosphate, an essential nutrient and phosphite, a phytotoxic phosphate analogue. The comparative analysis permitted us to identify molecular changes occurring in plants directly tied to phosphorus metabolism rather than ion sensing and transport. Our results show that the phosphorylation of RNA splicing proteins, kinases and chromatin‐modifying enzymes is an important, heretofore unstudied, component of the plant phosphate starvation response.