The changes in chlorophyll, solanine, and phytohormones during light-induced greening in postharvest potatoes

The changes in chlorophyll, solanine, and plant hormones during greening in postharvest potatoes exposed to light were investigated. The results showed that as potatoes under light turned green, the contents of chlorophyll and solanine sharply increased due to the upregulation of genes involved in their biosynthesis. At the end of storage, the chlorophyll and solanine content in potatoes stored under light were approximately 25.44 times and 1.62 times higher, respectively, compared to those stored in the dark. Light exposure inhibited the accumulation of indole-3-acetic acid (IAA) and gibberellin in potatoes, which was associated with the downregulation of their anabolic genes and the positive regulation of their catabolic genes. In contrast, light treatment increased the levels of ethylene, melatonin, brassinosteroid, abscisic acid and 6-benzylaminopurine compared to dark-stored potatoes. Correlation analysis revealed that solanine content was negatively correlated with IAA (r = −0.93) during greening, while chlorophyll content was positively associated with ethylene production (r = 0.91) but negatively related to IAA (r = −0.89). Our results suggested potential roles of phytohormones in regulating chlorophyll and solanine during greening in light exposed potatoes, which deserves further investigation.