Genome-wide analysis of heat shock proteins in C4 model, foxtail millet identifies potential candidates for crop improvement under abiotic stress.

Roshan Kumar Singh,Mehanathan Muthamilarasan,Jananee Jaishankar,Manoj Prasad,Anand Dangi,Shweta Shweta

doi:10.1038/srep32641

Roshan Kumar Singh, Mehanathan Muthamilarasan + Show 4 more

Open Access

https://doi.org/10.1038/srep32641

Copy DOI

Abstract

Heat shock proteins (HSPs) perform significant roles in conferring abiotic stress tolerance to crop plants. In view of this, HSPs and their encoding genes were extensively characterized in several plant species; however, understanding their structure, organization, evolution and expression profiling in a naturally stress tolerant crop is necessary to delineate their precise roles in stress-responsive molecular machinery. In this context, the present study has been performed in C4 panicoid model, foxtail millet, which resulted in identification of 20, 9, 27, 20 and 37 genes belonging to SiHSP100, SiHSP90, SiHSP70, SiHSP60 and SisHSP families, respectively. Comprehensive in silico characterization of these genes followed by their expression profiling in response to dehydration, heat, salinity and cold stresses in foxtail millet cultivars contrastingly differing in stress tolerance revealed significant upregulation of several genes in tolerant cultivar. SisHSP-27 showed substantial higher expression in response to heat stress in tolerant cultivar, and its over-expression in yeast system conferred tolerance to several abiotic stresses. Methylation analysis of SiHSP genes suggested that, in susceptible cultivar, higher levels of methylation might be the reason for reduced expression of these genes during stress. Altogether, the study provides novel clues on the role of HSPs in conferring stress tolerance.

Highlights

Showed in vitro chaperone activity[12]
41 non-redundant proteins belonging to HSP100 (SiHSP100), HSP90 (SiHSP90), HSP70 (SiHSP70), HSP60 (SiHSP60) and small HSPs (sHSP) (SisHSP) classes, respectively in foxtail millet
Though the results suggest that the higher methylation in SiHSP-27 gene in susceptible cultivar might be the reason for their reduced expression in stress conditions, further functional characterization is required to validate this hypothesis

Summary

Introduction

Showed in vitro chaperone activity[12]. Among poaceae members, analysis of HSPs was performed only in rice and barley; no comprehensive investigation has been conducted in the C4 panicoid model species, foxtail millet (Setaria italica L.). Foxtail millet has gained popularity among millet research community and several comprehensive researches have been pursued to identify and characterize the role of important stress-responsive gene families including NAC, WD40, AP2/ERF, C2H2 zinc finger, MYB, DCL, AGO, RDR, WRKY and ADP-ribosylation factors in conferring abiotic stress tolerance[15,16,17,18,19,20,21,22,23,24]. The present study was conducted to identify the HSPs encoded in foxtail millet genome and characterize them using in silico tools, and analyze their expression patterns during stress treatments. The study identified a potential candidate showing several fold upregulation in stress tolerant foxtail millet cultivar, and its heterologous over-expression in yeast system conferred tolerance to several abiotic stresses

Methods

Results

Conclusion