Genome-wide analysis of WRKY gene family in the sesame genome and identification of the WRKY genes involved in responses to abiotic stresses

Donghua Li,Yanxin Zhang,Linhai Wang,Pan Liu,Rong Zhou,Komivi Dossa,Jingyin Yu,Xiurong Zhang,Xin Wei

doi:10.1186/s12870-017-1099-y

Abstract

BackgroundSesame (Sesamum indicum L.) is one of the world’s most important oil crops. However, it is susceptible to abiotic stresses in general, and to waterlogging and drought stresses in particular. The molecular mechanisms of abiotic stress tolerance in sesame have not yet been elucidated. The WRKY domain transcription factors play significant roles in plant growth, development, and responses to stresses. However, little is known about the number, location, structure, molecular phylogenetics, and expression of the WRKY genes in sesame.ResultsWe performed a comprehensive study of the WRKY gene family in sesame and identified 71 SiWRKYs. In total, 65 of these genes were mapped to 15 linkage groups within the sesame genome. A phylogenetic analysis was performed using a related species (Arabidopsis thaliana) to investigate the evolution of the sesame WRKY genes. Tissue expression profiles of the WRKY genes demonstrated that six SiWRKY genes were highly expressed in all organs, suggesting that these genes may be important for plant growth and organ development in sesame. Analysis of the SiWRKY gene expression patterns revealed that 33 and 26 SiWRKYs respond strongly to waterlogging and drought stresses, respectively. Changes in the expression of 12 SiWRKY genes were observed at different times after the waterlogging and drought treatments had begun, demonstrating that sesame gene expression patterns vary in response to abiotic stresses.ConclusionsIn this study, we analyzed the WRKY family of transcription factors encoded by the sesame genome. Insight was gained into the classification, evolution, and function of the SiWRKY genes, revealing their putative roles in a variety of tissues. Responses to abiotic stresses in different sesame cultivars were also investigated. The results of our study provide a better understanding of the structures and functions of sesame WRKY genes and suggest that manipulating these WRKYs could enhance resistance to waterlogging and drought.

Highlights

Sesame (Sesamum indicum L.) is one of the world’s most important oil crops
Identification of WRKY family genes in sesame All Arabidopsis WRKY protein sequences were used as queries for the Basic Local Alignment Search Tool (BLAST) to identify sesame WRKY proteins
A Hidden Markov Model (HMM) search was performed against the sesame protein database using the WRKY-domain PF03106

Summary

Introduction

Sesame (Sesamum indicum L.) is one of the world’s most important oil crops. it is susceptible to abiotic stresses in general, and to waterlogging and drought stresses in particular. Sesame (Sesamum indicum L.) is an important, and probably the most ancient, oil crop and is grown widely in tropical and subtropical regions of the world [1]. Average sesame yields were alarmingly low between 2010 and 2014, with only 576.1 kg/ha being produced in 73 countries (http://faostat.fao.org). This low yield may be attributable to a variety of factors, abiotic stresses are certainly one of the most significant. The most important abiotic stresses that limit plant growth, development, and yield are drought and waterlogging. There is an urgent requirement to understand the molecular mechanisms that underlie the ability of sesame plants to tolerate both drought and waterlogging stresses

Results

Discussion

Conclusion