Chinese bayberry fruit treated with blue light after harvest exhibit enhanced sugar production and expression of cryptochrome genes

• Blue light treatment increased sugar content in bayberries.
• Blue light treated bayberries manifested higher expression of MrSPSs.
• A hexokinase and two cryptochrome genes were isolated from bayberry fruit.
• The expression levels of MrHXK1 and MrCRYs were up-regulated by blue light.

The effect of blue light exposure on sugar metabolism and cryptochrome gene expression in postharvest Chinese bayberry fruit was investigated. Results showed blue light treatment significantly increased the contents of sucrose, fructose, and glucose in bayberries during storage. Expression analysis revealed that transcripts of three sucrose phosphate synthase (MrSPS1, MrSPS2, and MrSPS3) were markedly induced by blue light treatment throughout the storage period, but increases in expression of two acid invertase genes (MrINV2 and MrINV3) were detected only at the beginning of storage. Meanwhile, a hexokinase gene (MrHXK1) and two genes of cryptochrome (MrCRY1 and MrCRY2) were isolated from bayberry fruit. The expression levels of MrHXK1 and MrCRY1 were up-regulated during blue light exposure only at the end of storage; however, significantly higher amounts of MrCRY2 transcripts were found in blue light exposed-fruit throughout the storage period. Results suggest that blue light treatment increases the sugar content in postharvest bayberries during storage by regulating the expression levels of genes involved in sugar metabolism. Additionally, the enhancement of transcripts of MrCRY1 and MrCRY2 might also be associated with the increase in sugar content in blue light exposed fruit.