Genome-wide identification and expression analysis of the WRKY gene family in five legumes

Abstract Background: WRKY is a transcription factor with 60 highly conserved amino acid region, regulating physiological processes and development in many plants and respond to a variety of abiotic stresses. However, the WRKY gene family has not been systematically studied in multiple legumes.Results: In this study, genome-wide analysis of five legumes (Phaseolus vulgaris, Medicago truncatula, Lotus japonicus, Glycine max, Cicer arietinum) identified 90, 108, 83, 185 and 61 WRKY genes, respectively. Besides, the chromosomal localization, phylogenesis, conserved motifs, gene structure and gene replication analysis were proceed for WRKY genes. The results showed that the legumes WRKY gene branches from the same evolutionary system have similar protein structures. In addition, by analyzing the transcriptome data we figured out that the expression level of WRKY differed in each tissue. Meanwhile, qRT-PCR was carried out to investigate the expression patterns of WRKY under abiotic stress. The results show that WRKY protein play crucial regulatory roles under salt and drought stress. Conclusions: In summary, these results comprehensively describes the WRKY gene of five legumes, which provides a theoretical basis for further exploring the biological functions of members of the WRKY gene family in legumes.