Insights into the functions of MYB29 and MYB28.1 involved in glucosinolate biosynthesis from Isatis indigotica Fort

Glucosinolates (GSLs) have garnered substantial attention for their essential functions in bolstering plant defense responses and potential anti-cancer effects. It was reported that MYB29 and MYB28 contribute to the accumulation of aliphatic GSLs in Arabidopsis thaliana, yet their roles in Isatis indigotica Fort. remain elusive. In this study, IiMYB29 and IiMYB28.1 were cloned, the expression patterns, subcellular localization and their functions in GSL biosynthesis were carried out. The results revealed that IiMYB29 exerted a stimulatory effect on plant growth and development, whereas IiMYB28.1 displays a negative regulatory influence. In GSL biosynthesis process, a comprehensive analysis identified 9 differentially expressed genes (DEGs) in the transgenic IiMYB29 plant, whereas 19 DEGs detected in the transgenic IiMYB28.1 plant. Furthermore, IiMYB29 induced a notable decline in GSL content, plummeting to a minimum level of 0.166 times of wild type. Conversely, IiMYB28.1 elicited a substantial increase in GSL content, peaking at a maximum of 2.264 times of wild type. The experimental results initially revealed the regulatory mechanisms of IiMYB29 and IiMYB28.1 on GSL synthesis, and laid the foundation for molecular breeding of I. indigotica.