Objective WRKY transcription factor family plays an important role in plant growth, development and stress resistance. The biological functions of WRKY gene family members involved in abiotic stress of Benincasa hispida Cogn. (wax gourd) were explored.

Method WRKY members of wax gourd were identified based on the genome database of wax gourd. The protein physicochemical properties, phylogeny, conserved motifs and cis-acting elements of the members of the BhWRKY gene family was systematically analyzed by bioinformatics method. And the expression of wax gourd WRKY was analyzed by qPCR.

Result The results showed that there were 57 members in the BhWRKY gene family with amino acid numbers ranging from 126 to 650 and molecular weight ranging from 13.92 to 71.68 kD. The isoelectric point of protein ranged from 4.61 to 9.69. According to phylogenetic tree, the family was divided into 3 groups, and the second group was further divided into 5 subgroups. The number of WRKY exons of wax gourd ranged from 2 to 6. Chromosomal mapping analysis showed that 56 genes were located on 12 chromosomes, and one gene was not located on the chromosome. The conserved Motif 1 and Motif 3 were found in 56 genes, and the same group had similar conserved motif structure. Meanwhile, it was also found that the promoters of the BhWRKY genes all contained cis-responsive elements and hormone response elements related to stress response. WRKYs were specifically expressed in different tissues and fruit development stages of wax gourd. RT-PCR result showed that abiotic stress and hormone treatment could induce the expression of some BhWRKY genes.

Conclusion A total of 57 WRKY genes of wax gourd are identified and members of the same subgroup have similar structures. There are differences in the expression of 57 WRKY genes in different tissues. Among them, BhWRKY2, BhWRKY5, BhWRKY39, BhWRKY11, BhWRKY31 and BhWRKY53 participate in different stress responses.