Genome-Wide Characteristics of GH9B Family Members in Melon and Their Expression Profiles under Exogenous Hormone and Far-Red Light Treatment during the Grafting Healing Process.

β-1,4-glucanase can not only promote the wound healing of grafted seedlings but can also have a positive effect on a plant's cell wall construction. As a critical gene of β-1,4-glucanase, is involved in cell wall remodeling and intercellular adhesion and plays a vital role in grafting healing. However, the family members have not yet been characterized for melons. In this study, 18 were identified from the melon genome, and these were located on 15 chromosomes. Our phylogenetic analysis of these genes and genes from other species divided them into three clusters. The gene structure and conserved functional domains of in different populations differed significantly. However, responded to cis elements such as low temperature, exogenous hormones, drought, and injury induction. The expression profiles of were different. During the graft healing process of the melon scion grafted onto the squash rootstock, both exogenous naphthyl acetic acid (NAA) and far-red light treatment significantly induced the upregulated expression of related to the graft healing process. The results provided a technical possibility for managing the graft healing of melon grafted onto squash by regulating expression.