The carotenoid cleavage dioxygenase (CCD) gene family in plants comprises two subfamilies: CCD and 9-cis-epoxycarotenoid dioxygenase (NCED). Genes in the
NCED subfamily are mainly involved in plant responses to abiotic stresses such as salt, low temperature, and drought. Members of the
NCED subfamily are the most important rate-limiting enzymes in the biosynthesis of abscisic acid (ABA). In the present study, genome-wide analysis was performed to identify
CCD gene members in six Cucurbitaceae species, including watermelon (
Citrullus lanatus), melon (
Cucumis melo), cucumber (
C.sativus), pumpkin (
Cucurbita moschata), bottle gourd (
Lagenaria siceraria), and wax gourd (
Benincasa hispida). A total of 10, 9, 9, 13, 8, 8
CCD genes were identified in the six species, respectively, and these genes were unevenly distributed in different chromosomes. Phylogenetic analysis showed that
CCD genes of the six species clustered into two subfamilies:
CCD and
NCED, with five and three independent clades, respectively. The number of exons ranged from 1 to 15, and the number of motifs were set to 15 at most. The cis-acting elements analysis showed that a lot of the cis-acting elements were implicated in stress and hormone response. Melon seedlings were treated with salt, low temperature, drought, and ABA, and then tissue-specific analysis of
CCDs expression were performed on the root, stem, upper leaf, middle leaf, female flower, male flower, and tendril of melon. The results showed that genes in
CCD family exhibited various expression patterns. Different
CCD genes of melon showed different degrees of response to abiotic stress. This study presents a comprehensive analysis of
CCD gene family in six species of Cucurbitaceae, providing a strong foundation for future studies on specific genes in this family.
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