The transcription factor StMYB113 regulates light-induced greening by modulating steroidal glycoalkaloid biosynthesis in potatoes (Solanum tuberosum L.)

AbstractDuring harvesting, storage, transportation, and processing, potato (Solanum tuberosum L.) tubers undergo greening after exposure to light, leading to the accumulation of toxic glycoside alkaloids, resulting in quality deterioration and economic losses. However, the underlying mechanisms are unclear. This study compared the transcriptome and proteome differences among four potato cultivars during the light-induced greening process, identifying 3,751 unique proteins (high confidence; ≥91.7%). The levels of enzymes involved in steroidal glycoalkaloid biosynthesis varied among the cultivars. In addition, coexpression network analysis of the transcriptomic data identified the transcription factor MYB113 (Soltu.DM.10G020780.1) as a potential positive regulator of steroidal glycoalkaloid biosynthesis. The dual-luciferase assay revealed that StMYB113 could bind to the promoters of steroidal glycoalkaloid biosynthesis-related genes and activate them. The transgenic lines overexpressing Solanum tuberosum L. Myb domain protein (StMYB113) exhibited greater mRNA abundance of these genes and elevated levels of steroidal glycoalkaloids. This study provided a theoretical basis for exploring the impact of light on the synthesis of solanine in potatoes.