Comparative genomic analysis of expansin superfamily gene members in zucchini and cucumber and their expression profiles under different abiotic stresses

Abstract

Zucchini and cucumber belong to the Cucurbitaceae family, a group of economical and nutritious food plants that is consumed worldwide. Expansin superfamily proteins are generally localized in the cell wall of plants and are known to possess an effect on cell wall modification by causing the expansion of this region. Although the whole genome sequences of cucumber and zucchini plants have been resolved, the determination and characterization of expansin superfamily members in these plants using whole genomic data have not been implemented yet. In the current study, a genome-wide analysis of zucchini (Cucurbita pepo) and cucumber (Cucumis sativus) genomes was performed to determine the expansin superfamily genes. In total, 49 and 41 expansin genes were identified in zucchini and cucumber genomes, respectively. All expansin superfamily members were subjected to further bioinformatics analysis including gene and protein structure, ontology of the proteins, phylogenetic relations and conserved motifs, orthologous relations with other plants, targeting miRNAs of those genes and in silico gene expression profiles. In addition, various abiotic stress responses of zucchini and cucumber expansin genes were examined to determine their roles in stress tolerance. CsEXPB-04 and CsEXPA-11 from cucumber and CpEXPA-20 and CpEXPLA-14 from zucchini can be candidate genes for abiotic stress response and tolerance in addition to their roles in the normal developmental processes, which are supported by the gene expression analysis. This work can provide new perspectives for the roles of expansin superfamily genes and offers comprehensive knowledge for future studies investigating the modes of action of expansin proteins.