Abstract
BackgroundThe WRKY transcription factor family plays significant roles in biotic and abiotic stress responses, which has been associated with various biological processes in higher plants. However, very little is known regarding the structure and function of WRKY genes in maize.ResultsIn this study, a total of 140 ZmWRKY proteins encoded by 125 ZmWRKY genes were eventually identified in maize. On the basis of features of molecular structure and a comparison of phylogenetic relationships of WRKY transcription factor families from Arabidopsis, rice and maize, all 140 ZmWRKY proteins in maize were divided into three main groups (Groups I, II and III) and the Group II was further classified into five subgroups. The characteristics of exon-intron structure of these putative ZmWRKY genes and conserved protein motifs of their encoded ZmWRKY proteins were also presented respectively, which was in accordance with the group classification results. Promoter analysis suggested that ZmWRKY genes shared many abiotic stress-related elements and hormone-related elements. Gene duplication analysis revealed that the segmental duplication and purifying selection might play a significant role during the evolution of the WRKY gene family in maize. Using RNA-seq data, transcriptome analysis indicated that most of ZmWRKY genes displayed differential expression patterns at different developmental stages of maize. Further, by quantitative real-time PCR analysis, twenty-one ZmWRKY genes were confirmed to respond to two different abiotic stress treatments, suggesting their potential roles in various abiotic stress responses. In addition, RNA-seq dataset was used to conduct weighted gene co-expression network analysis (WGCNA) in order to recognize gene subsets possessing similar expression patterns and highly correlated with each other within different metabolic networks. Further, subcellular localization prediction, functional annotation and interaction analysis of ZmWRKY proteins were also performed to predict their interactions and associations involved in potential regulatory network.ConclusionsTaken together, the present study will serve to present an important theoretical basis for further exploring function and regulatory mechanism of ZmWRKY genes in the growth, development, and adaptation to abiotic stresses in maize.
Highlights
The WRKY transcription factor family plays significant roles in biotic and abiotic stress responses, which has been associated with various biological processes in higher plants
As depicted in the constructed evolutionary tree (Fig. 1), the 140 ZmWRKY proteins were classified into three main Groups (I, II and III), and the Group II proteins were further categorized into 5 subgroups (IIa, IIb, IIc, IId and IIe)
To reveal how conservative the heptapeptide WRKYGQK and zinc-finger-like domains were in each group, the sequence logos were produced by the WebLogo online program to exhibit the conservation at each residue position, and the sequence alignment were further performed by DNAMAN 7.0 (Fig. S1)
Summary
The WRKY transcription factor family plays significant roles in biotic and abiotic stress responses, which has been associated with various biological processes in higher plants. As a result of the global environmental vagaries, various environmental stresses including biotic and abiotic stresses have brought huge threat to the global maize production [2, 3] Abiotic stresses, such as extreme temperature, high salinity and drought and so on, have been confirmed to be one of the main factors for the losses of corn yield worldwide. The Group I members contain two WRKY domains with C2H2 zinc-finger-like motifs. The Group II members contain a single WRKY domain including a C2H2 zinc-finger-like motif. The WRKY TFs containing a single WRKY domain with a C2HC zinc-finger-like motif belong to the Group III [8]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
