Abstract：Plant WRKY transcription factors play important regulatory roles in plant response to low temperature. However, there are few researches about genome-wide identification and characterization of melon (Cucumis melo) WRKY genes and their expression patterns under low-temperature stress. Thus, in this study, the genome-wide identification of WRKY genes and bioinformatics analysis were carried out in melon, and the expression patterns under low-temperature stress were detected by qRT-PCR. The results showed that there were 59 CmWRKYs identified in melon, which unevenly distributed on the chromosomes. Based on phylogenetic analysis, the CmWRKY proteins were classified into 3 groups (Ⅰ~Ⅲ) and the second group was further divided into 5 subgroups (Ⅱa~e). Synteny analysis showed that there were 28 collinear gene pairs in melon and Arabidopsis thaliana WRKY gene family and 10 pairs of CmWRKYs were identified as segmental duplication. Cis-regulatory elements related to stress and hormone responses were found in the promoters of CmWRKYs. Gene Ontology (GO) analysis displayed that CmWRKYs widely participated in physiological processes such as biological process, cellular component and molecular function. The qRT-PCR detection showed that the expression of 11 CmWRKYs was significantly up-regulated under low temperature stress. The results of this study can provide reference for further cloning of CmWRKYs and analysis of low temperature tolerance function.
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