The LasmiR858-MYB111 module enhances the antioxidant capacity of green leaf lettuce by promoting flavonoid biosynthesis

Flavonoids are secondary metabolites found in plants that possess antioxidant properties. MicroRNAs are small non-coding RNAs that play a crucial role in regulating gene expression and are involved in both developmental and metabolic pathways. The study analysed the differences in indices of lettuce with different leaf colours, a STTM-miR858 silencing vector was constructed using molecular biology techniques, and genetically modified lettuce plants with reduced expression of Las-miR858 were obtained. The interaction mechanism between miR858 and MYB111 was predicted and verified. The study found that reduced expression of miR858 regulated its target MYB111, which subsequently stimulated the expression of key enzyme genes in the flavonoid biosynthesis pathway. This resulted in the accumulation of flavonoids in lettuce, enhancing its antioxidant capacity. This study is the first to explain the regulation of flavonoids by the LasmiR858 network, providing a theoretical and empirical basis and genetic resources for the study of lettuce flavonoid mechanisms.