Supplemental Lighting Enhances Blueberry Fruit Quality and Flavonoid Accumulation Associated with VcMYBPA1 Expression in Greenhouses.

The efficient utilization of light energy is a powerful guarantee to improve the production efficiency of agricultural and forestry facilities. This study investigated the effects of early-morning supplemental lighting on the yield and fruit quality of greenhouse-grown blueberry and examined the physiological and transcriptional responses associated with anthocyanin accumulation. The findings indicate that supplemental lighting significantly promoted fruit development, accelerated maturation, and increased fruit size, weight, sugar, vitamin C content and the antioxidant capacity of the fruits, especially the anthocyanin content. Transcriptomic analysis revealed that, during fruit ripening, the differentially up-regulated genes activated by supplemental lighting primarily involved transmembrane transport functions, membrane components, and redox enzyme activity. Conversely, the down-regulated genes were mainly involved in organic acid metabolism, photosynthesis and photosystem functions. Pathways associated with the up-regulated genes were largely connected to anthocyanin biosynthesis and galactose metabolism. Furthermore, the anthocyanin biosynthesis showed affiliations with several distinct genes (such as 4CL and UFGT) that were differentially up-regulated, along with the MYB transcription factor. Notably, in blueberries exposed to supplemental lighting, VcMYBPA1 showed a strong positive correlation with UFGT. Further investigations demonstrated that VcMYBPA1 was mainly localized in the nucleus, and its overexpression significantly increased the expression levels of AtDFR, AtANS, and AtUFGT in Arabidopsis. This study highlights the crucial role of supplemental lighting in enhancing blueberry yield and quality and provides an effective way to further improve the utilization of light-assisted agricultural technologies.