The use of a lignin monomer synthetic gene 4-CL encoding 4-coumarate: CoA ligase from Populus tomentosa in increasing Sclerotinia resistance and lodging resistance. The 4-CL gene is responsible for catalyzing various cinnamic acids and their derivatives to produce respective coenzyme A esters, involved in the synthesis of various downstream secondary products, and is the key gene in the regulation of lignin synthesis. Results of the study show that, increase of lignin content improves plant's resistance against pathogenic infection, enhances the stem strength of rape, and thus significantly improves the lodging resistance. Specifically, the result shows that lignin content of transgenic rape increases more than 10% compared to lignin content of recipient control; lesion extension area of transgenic plant leaves decreases around 30% compared to recipient control; and stem strength of transgenic plant increases up to around 20% compared to control.