Lignin and Flavonoid Biosynthesis are Regulated Cooperatively Under Uv-B Stress and Botrytis Cinerea Infection

Phenylpropanoid metabolism is one of the most important metabolisms in plants. Flavonoid biosynthesis and lignin biosynthesis are two branches of phenylpropanoid metabolism. They share the early steps and both play roles in the survival of plant under diverse biotic and abiotic stresses. However, a preference on lignin biosynthesis and suppression on flavonoid biosynthesis has been reported in studies of biotic stress. To verify whether this phenomenon is common in plant, a study of Morus leaf under UV-B stress and Botrytis cinerea infection was performed. Compared with changes after UV-B stress, no suppression of flavonoid biosynthesis was observed under B. cinerea infection, which is biotic stress, no matter on transcriptome level, proteome level or metabolome level. Results showed that lignin biosynthesis and flavonoid biosynthesis were regulated cooperatively both under UV-B stress and B.s cinerea infection. And the accumulation of flavonoids and flavonoid derivates might be a main strategy of B. cinerea resistance and UV-B resistance in Morus leaf.