Genome-wide analysis of antioxidant enzyme gene families involved in drought and low-temperature responses in Apple (Malus domestica)

Antioxidant enzymes were well-known for reactive oxygen scavenging and protecting cells from oxidative damage in multiple biotic and abiotic stresses. Aimed to overview of antioxidant enzyme gene families and screen for drought and low-temperature response members, the whole apple antioxidant enzyme genes in apple genome were studied. Out of 73candidates in seven antioxidant enzyme gene families among the entire apple genome, a total of 49 genes were identified, showed more antioxidant enzyme gene members than those in other plant species. A phylogenetic tree based on predicted functional domains and motifs of apple and Arabidopsis antioxidant enzymes revealed 19 putative drought or low-temperature response genes, and 9 out 19 genes belong to five families responded to both drought and low-temperature stresses. Subsequently, cis-elements in those nine antioxidant enzyme gene promoters were examined and abundant elements involved in multiple hormone regulation and abiotic stresses response, including drought and low-temperature were found. The tissue expression specificity for those nine members in eight kinds of tissues was also examined. Screening and identifying both drought and low-temperature response genes provide useful information to understand gene functions and promote application of antioxidant enzyme genes in apple abiotic resistance breeding.