Hydrogen peroxide receptors regulate chilling injury of banana fruit during low-temperature storage

Low temperature is widely used for most postharvest fruit storage, but the occurrence of chilling injury (CI) in banana fruit stored at below 13 degrees C severely reduces the marketability. The excess accumulation of reactive oxygen species (ROS) can result in the CI occurrence of banana fruit during low-temperature storage, but the roles of ROS mediated by hydrogen peroxide receptors (hydrogen peroxide-induced Ca2+ increases (HPCA)-LIKE, HPCALs) remain unclear. In this study, banana fruit were treated with hydrogen peroxide scavenger (1,3dimethylthiourea, DMTU) to investigate the mechanism by which HPCALs mediate ROS to participate in the CI initiation in banana fruit during storage at 6 degrees C. Application of 5.0 mM DMTU significantly decreased the CI index and the respiration rate, and activated the antioxidant system of banana fruit during low-temperature storage. The transcript levels of HPCAL genes were significantly affected by the DMTU treatment. Further analyses suggested that some transcription factors, such as NAC, MYB, WRKY, Dof and CBF families, may regulate the expressions of HPCAL genes, thereby contributing to the regulation of CI of banana fruit during lowtemperature storage. These findings provide new insights into the roles of HPCALs in the ROS-mediated CI of banana fruit during low-temperature storage.