Genome-wide identification and expression analysis of the VQ gene family in Cucurbita pepo L.

VQ protein is a plant specific protein, which plays an important role in plant growth and development and biological and abiotic stress response. This study aimed to systematically analyze for the first time the VQ of Cucurbita pepo and understand their expression patterns in response to different stimuli. Herein, 44 VQ genes were identified, which were divided into eight groups (I–VIII) based on phylogenetic analysis. Two genes (CpVQ1 and CpVQ2) could not be located on the chromosome, whereas the remaining CpVQ genes were randomly distributed on the chromosomes, except for chromosomes 15 and 18. Noteworthy, the main event driving the expansion of the VQ gene family was chromosome fragment duplication. Based on qRT-PCR analysis, VQ genes are expressed in different tissues, and VQ genes are differentially regulated under a variety of abiotic stresses and powdery mildew stress, indicating that they play an important role in plant stress response and other aspects. This report presents the first systematic analysis of VQ genes from C. pepo and provides a solid foundation for further research of the specific functions of VQ proteins.