Phosphoproteins regulated by heat stress in rice leaves

Huaqin He,Jiechao Zhou,Xinhai Chen,Yongfei Wang,Wenfeng Zhang,Qiaobin Yang,Yuqin Ke,Baoqian Zhang

doi:10.1186/1477-5956-9-37

Abstract

BackgroundHigh temperature is a critical abiotic stress that reduces crop yield and quality. Rice (Oryza sativa L.) plants remodel their proteomes in response to high temperature stress. Moreover, phosphorylation is the most common form of protein post-translational modification (PTM). However, the differential expression of phosphoproteins induced by heat in rice remains unexplored.MethodsPhosphoprotein in the leaves of rice under heat stress were displayed using two-dimensional electrophoresis (2-DE) and Pro-Q Diamond dye. Differentially expressed phosphoproteins were identified by MALDI-TOF-TOF-MS/MS and confirmed by Western blotting.ResultsTen heat-phosphoproteins were identified from twelve protein spots, including ribulose bisphos-phate carboxylase large chain, 2-Cys peroxiredoxin BAS1, putative mRNA binding protein, Os01g0791600 protein, OSJNBa0076N16.12 protein, putative H(+)-transporting ATP synthase, ATP synthase subunit beta and three putative uncharacterized proteins. The identification of ATP synthase subunit beta was further validated by Western-blotting. Four phosphorylation site predictors were also used to predict the phosphorylation sites and the specific kinases for these 10 phosphoproteins.ConclusionHeat stress induced the dephosphorylation of RuBisCo and the phosphorylation of ATP-β, which decreased the activities of RuBisCo and ATP synthase. The observed dephosphorylation of the mRNA binding protein and 2-Cys peroxiredoxin may be involved in the transduction of heat-stress signaling, but the functional importance of other phosphoproteins, such as H+-ATPase, remains unknown.

Highlights

High temperature is a critical abiotic stress that reduces crop yield and quality
Lee et al [8] found that Heat shock proteins (HSPs) and energy- and metabolism-associated proteins were the major proteins affected by a high temperature of 42°C in leaves
Pro-Q diamond staining of phosphoproteins Total proteins extracted from the leaves of rice in response to heat stress were separated by 2-DE and stained with Pro-Q Diamond dye

Summary

Introduction

High temperature is a critical abiotic stress that reduces crop yield and quality. Rice (Oryza sativa L.) plants remodel their proteomes in response to high temperature stress. The inherent immobility of plants limits their abilities to avoid stress, requiring them to cope with abiotic stresses through innate defense mechanisms [1] Some abiotic stresses, such as drought, salinity, extreme temperatures, chemical toxicity and oxidative stresses, are serious threats to agriculture and abiotic stresses have become the primary cause of crop loss worldwide, reducing average yields for most major crop plants by more than 50% [2]. The overall global temperature has Several physiological mechanism of rice plants for heat tolerance had been identified, including the selectively upregulated of Rubisco activase large isoform, the increase of multiple enzymes of the Calvin Cycle, a fall in FerredoxinNADP(H) oxidoreductase (FNR) and a consistent increase in expression of a thiamine biosynthesis protein (THI1) [11]. Lignification-related proteins were regulated by high temperature, and distinct proteins related to protection were up-regulated at different high temperatures, indicating that different strategies were adopted at different levels of high temperature: the higher the temperature, the greater the involvement of the protection machineries [6]

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