Quantitative proteomics analysis reveals the tolerance of wheat to salt stress in response to Enterobacter cloacae SBP-8.

Rajnish Prakash Singh,Shahid Khan,Prabhat Nath Jha,Ashish Runthala,Guangxiao Yang

doi:10.1371/journal.pone.0183513

Abstract

Salinity stress adversely affects the plant growth and is a major constraint to agriculture. In the present study, we studied the role of plant growth promoting rhizobacterium (PGPR) Enterobacter cloacae SBP-8 possessing ACC deaminase activity on proteome profile of wheat (Triticum aestivum L.) under high salinity (200 mM NaCl) stress. The aim of study was to investigate the differential expressed protein in selected three (T-1, T-2, T-3) treatments and absolute quantification (MS/MS analysis) was used to detect statistically significant expressed proteins. In this study, we investigated the adaptation mechanisms of wheat seedlings exposed to high concentration of NaCl treatment (200 mM) for 15 days in response to bacterial inoculation based on proteomic data. The identified proteins were distributed in different cellular, biological and molecular functions. Under salt stress, proteins related to ion-transport, metabolic pathway, protein synthesis and defense responsive were increased to a certain extent. A broader comparison of the proteome of wheat plant under different treatments revealed that changes in some of the metabolic pathway may be involved in stress adaption in response to PGPR inoculation. Hierarchical cluster analysis identified the various up-regulated/down-regulated proteins into tested three treatments. Our results suggest that bacterial inoculation enhanced the ability of wheat plant to combat salt stress via regulation of transcription factors, promoting antioxidative activity, induction of defense enzymes, lignin biosynthesis, and acceleration of protein synthesis.

Highlights

Soil salinity is a major problem in the agriculture sector that inhibits the crop growth and productivity
Bacterial inoculation enhanced the expression of ‘Casparian strip membrane protein’(CASP) and ‘Xyloglucanendo transglycosylase (XET)’ as compared to uninoculated plants treated with salt stress
Based on protein profiling using gel-free method, the present study reports the amelioration of salt stress in wheat by a plant growth promoting bacterium Enterobacter cloacae SBP-8 which modulates expression of different proteins involved in maintenance of cell structure, division, protein synthesis, proteolysis, photosynthesis, defense, fatty acid synthesis, homeostasis, and other metabolic pathways

Summary

Introduction

Soil salinity is a major problem in the agriculture sector that inhibits the crop growth and productivity. It is estimated that around 20% of cultivated land, and up to 50% of all irrigated land are severely affected by high salinity effects worldwide. Most of this salt-affected land has arisen from the accumulation of salts over long periods of time in arid and semiarid zones [1]. The irrigation with salinized water and scarce rain fall contribute to further increased salt stress that leads to decrease in crop productivity [2].

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