The mechanism of gibberellins treatment suppressing kiwifruit postharvest ripening processes by transcriptome analysis

Gibberellins (GAs) control numerous processes in plants, including fruit ripening. However, the role of GAs in kiwifruit ripening is not well characterized. Here, we noticed that GA3 treatment in postharvest kiwifruit delayed the ripening process and many physiological traits were detected such as firmness, starch/total soluble solid content, cell-wall components (pectin, cellulose and hemicellulose), ethylene and ester production, and ascorbic acid (vitamin C) concentration. Transcriptome analysis supplied a molecular basis for investigating the inhibiting mechanism of GA3 and metabolic variations during kiwifruit ripening. A total of 3116 differently expressed genes (DEGs) were identified, including 51 genes involved in plant hormone signal transduction pathways and 36 structural genes related to these physiological traits. 16 major DEGs were analyzed by real-time PCR during the whole storage period. The expression of most of them was significantly suppressed by GA3 treatment, such as two ethylene biosynthesis genes (ACOs ), two β-amylase (BAMs), five cell-wall modification genes, one GA2ox, and one GA receptor GID1, whereas the expression of Actinidia29942 (JAZ) was enhanced by GA3 treatment. Correlation analysis between multiple physiological indicators and candidate genes showed that GA3 could regulate kiwifruit postharvest ripening effectively and comprehensively. Together, these GA-responsive genes may play important roles in controlling kiwifruit ripening, and GA treatment could be a promising approach for the preservation of postharvest kiwifruit.