Genome-wide identification of the radiation sensitivity protein-23 (RAD23) family members in apple (Malus×domestica Borkh.) and expression analysis of their stress responsiveness

Radiation sensitivity proteins-23 (RAD23) are DNA repair factors participate in the ubiquitin/proteasome system (UPS). Although the genome-wide analysis of RAD23 family members has been conducted in some species, little is known about RAD23 genes in apple (Malus×domestica Borkh.). We analyzed this gene family in M. domestica in terms of genomic locations, protein and promoter structures, and expressions in response to stresses. Various members showed a ubiquitous pattern of expression in all selected apple parts. Their expressions were altered under chilling, heat, and hydrogen peroxide treatments, as well as abscisic acid (ABA) treatment and water deficiency, suggesting their possible roles in plant stress responses. These results provide essential information about RAD23 genes in apple and will contribute to further functional studies.