Genome-Wide Identification of the Dehydrin Genes in the Cucurbitaceae Species

Dehydrins (DHNs) are hydrophilic proteins with conserved lysine-rich K-segment, which belong to Group II of the late embryogenesis abundant (LEA) protein family. DHNs are considered as molecular chaperons playing important roles in abiotic stress tolerance. In this study, DHN genes were identified through genome-wide searches in five Cucurbitaceae species, including cucumber, wild cucumber, melon, watermelon, and bitter gourd. Three to five DHN genes were found in each of the five species, which were further divided into several protein architecture types based on the presence and order of the major conserved motifs such as K-, Y-, and S-segments. In silico expression profiling using RNA-Seq data revealed high expression of SK3-type DHN gene and low expression of other type DHN genes in cucumber and melon. In silico promoter analysis identified a number of cis-acting element-like sequences related to abiotic stress-response such as DRE and ABRE in 2-kb putative promoter sequences. DHN genes identified in this study will be valuable for understanding the stress response mechanism as well as assisting molecular breeding in Cucurbitaceae crops.