Molecular cloning and expression analysis of hydrogen peroxide sensors under H2O2 and ROS inhibitor treatment in 'Kyoho' grape berry.

• Four hydrogen peroxide sensors VvHPCA1-4 in grape are identified. • H 2 O 2 and ROS inhibitor change ROS scavenge system and VvHPCAs ' expression levels. • VvHPCA is cytomembrane protein with stress-responsive cis-acting elements in promoter. • VvHPCAs respond to ROS stress. Hydrogen peroxide is an important factor involved in the senescence and quality deterioration of postharvest fruit. However, few studies have examined hydrogen peroxide sensors and their expression patterns in grape. Here, postharvest grape berries were treated with H 2 O 2 and the ROS inhibitor hypotaurine (HT). HT reduced the H 2 O 2 content by increasing ROS-scavenging enzyme activity, whereas H 2 O 2 accelerated senescence. Four hydrogen peroxide sensors (VvHPCA1 , 2 , 3 , and 4) were identified and isolated from the grape genome. Sequence analysis indicated that VvHPCAs shared a conserved structure, including the LRR-RK and hydrogen peroxide (HP) domains, with other homologous hydrogen peroxide sensor genes. Furthermore, the expression patterns of the four VvHPCAs were investigated under H 2 O 2 and HT treatment in grape. The expression levels of the four VvHPCA s were lower in grape berries treated with HT than in grape berries treated with H 2 O 2 or water treatment (Control) in at least one of the sampling points during storage. VvHPCAs are cytomembrane proteins with stress-responsive cis-acting elements in their promoters, indicating that these four identified VvHPCAs might function as hydrogen peroxide sensors in grape and regulate hydrogen peroxide signaling and metabolism. Thus, VvHPCAs are capable of responding to postharvest ROS stress. These findings provided new insight into the function of these four VvHPCAs, which are potential candidate genes involved in regulating ROS stress in grape. [ABSTRACT FROM AUTHOR]