Identification and Characterization of the Diverse Stress-Responsive R2R3-RMYB Transcription Factor from Hibiscus sabdariffa L.

Bahaeldeen Babikar Mohamed,Bushra Rashid,Zarnab Ahmad,Tayyab Husnain,Sameera Hassan,Muhammad Bilal Sarwar,Beenish Aftab

doi:10.1155/2017/2763259

Abstract

Various regulatory proteins play a fundamental role to manage the healthy plant growth under stress conditions. Differential display reverse transcriptase PCR and random amplification of cDNA ends (RACE) was used to explore the osmotic stress-responsive transcripts. We identified and characterized the salt stress-responsive R2R3 type RMYB transcription factor from Hibiscus sabdariffa which has an open reading frame of 690 bp, encoding 229 long chain amino acids. In silico analysis confirmed the conserved R2 and R3 domain as well as an NLS-1 localization site. The deduced amino acids of RMYB shared 83, 81, 80, 79, 72, 71, and 66% homology with Arabidopsis thaliana, Glycine max, Oryza sativa, Zea maize, Malus domestica, Populus tremula × Populus alba, and Medicago sativa specific MYB family, respectively. We observed the gene upregulation in stem, leaf, and root tissue in response to abiotic stress. Furthermore, RMYB gene was cloned into plant expression vector under CaMV35S promoter and transformed to Gossypium hirsutum: a local cotton cultivar. Overexpression of RMYB was observed in transgenic plants under abiotic stresses which further suggests its regulatory role in response to stressful conditions. The RMYB transcription factor-overexpressing in transgenic cotton plants may be used as potential agent for the development of stress tolerant crop cultivars.

Highlights

Drought and salinity are the most devastating environmental stresses, which cause major reductions in crop productivity and quality
MYB family of transcription factors is a large set of proteins that is mostly involved in an array of functions regarding growth and development, primary and secondary metabolism, cell fate regulation, and response to biotic and abiotic stresses [16]
Several biotic and abiotic stress-responsive transcripts have been identified from different plant species by this methodology such as tomato, rice, barley, Arabidopsis, sunflower, and cotton

Summary

Introduction

Drought and salinity are the most devastating environmental stresses, which cause major reductions in crop productivity and quality. About 20% of the total cultivated land and 33% of irrigated agricultural land are affected by salinity with 10% annual increase due to saline water supply and poor agricultural practices [1] These statistics make salinity a mighty abiotic stress factor that limits the plant growth root to shoot ratio due to limited photosynthetic activity. Regulation of gene expression under salinity stress includes a wide array of mechanisms that are used by plants to up or downregulate the production of specific gene products (mRNA to protein) These genes involve three major categories: (i) those that are involved in signaling cascade and in transcriptional control (transcription factor), such as MyC, MAP, and SOS kinases phospholipids and transcription factors such as HSF and CBF/DREB, MYB, bZIp, bHLH, WRKY, and NAC transcription factors; (ii) those that function directly in the protection of membranes and proteins, such as heat shock protein (HSPs) and chaperones, and late

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