Overexpression of TkMYC2 enhances drought tolerance and rubber-producing capacity in transgenic Taraxacum kok-saghyz.

MAIN CONCLUSION: TkMYC2 mediates jasmonate-induced drought resistance and rubber biosynthesis simultaneously in Taraxacum kok-saghyz. Taraxacum kok-saghyz (T. kok-saghyz) is an important natural rubber-producing plant, yet its cultivation is often limited by drought stress, and the regulatory mechanisms underlying rubber biosynthesis and laticifer development remain incompletely understood. This study focused on TkMYC2, a core transcription factor in the jasmonate (JA) signaling pathway. Through homologous and heterologous genetic transformation, we systematically elucidated its dual functions in conferring drought tolerance and driving rubber biosynthesis. TkMYC2 expression was induced by both drought and methyl jasmonate (MeJA). Overexpression of TkMYC2 significantly enhanced the tolerance of transgenic plants to osmotic and drought stress by activating the antioxidant system (SOD, POD, CAT), maintaining ROS homeostasis, and reducing membrane lipid peroxidation. Using yeast two-hybrid and bimolecular fluorescence complementation assays, we demonstrated a direct physical interaction between TkMYC2 and TkJAZ11, a key repressor in the JA pathway. Phenotypic analyses showed that TkMYC2 overexpression promoted root thickening, laticifer development, and natural rubber accumulation, functionally supporting the hypothesis that rubber biosynthesis drives laticifer development. In summary, TkMYC2 acts as a critical molecular hub concurrently regulating drought stress response and rubber biosynthesis, providing new insights into jasmonate-mediated coordination of stress resilience and secondary metabolism, and offering a genetic resource for molecular breeding of T. kok-saghyz with enhanced yield and stress tolerance.