Objectives:Established a JA-sensitivity assisted method to screen nicotine mutants from tobacco(N.tabacum L.)activation-tagging population.Methods:Seeds of 3000 tobacco mutant lines(T1)from an activation-tagging population were provided by the Chinese Tobacco Research Institute.The mutant lines were generated from T0 transgenic plants that were transformed with the activation tagging T-DNA vector pSKI015 with the tobacco(N.tabacum L.)cultivar "Honghuadajinyuan"(HD).In this screening approach,the mutants were firstly screened for abnormal JA responses in seed germination and root elongation,and then the nicotine content and expression levels of nicotine synthetic genes in the mutants with altered JA response were determined to select nicotine synthetic mutants.Result: Using 10μM MeJA as selection pressure,we screened out 48 mutants from 3000 T1 lines which exhibit abnormal germination time and root length.From these JA-response mutants,we obtained 10 nicotine synthetic mutants,which include 5 mutants maintaining stable low/high nicotine content in 3 generations and displaying altered expression patterns of nicotine synthetic genes.Conclusion:We have successfully obtained 5 nicotine mutants that maintained stable nicotine contents and similar JA responses in 3 generations.These results suggest a feasible approach to identify JA signaling regulators involved in nicotine biosynthesis via JA-sensitivity assisted mutant screening.