Fuente: WIPO "tobacco agriculture" The invention discloses an NtMYC2a gene mutant capable of increasing nicotine content of tobacco leaves and application of the NtMYC2a gene mutant, the nucleotide sequence of the NtMYC2a gene mutant capable of increasing nicotine content of tobacco leaves is shown as SEQ ID NO: 3, and compared with an NtMYC2a gene with the nucleotide sequence shown as SEQ ID NO: 1, the NtMYC2a gene mutant capable of increasing nicotine content of tobacco leaves has G-A mutation at the 490th site. According to the NtMYC2a gene mutant capable of increasing the nicotine content of the tobacco leaves and the application thereof, the NtMYC2a gene mutant capable of increasing the nicotine content of the tobacco leaves is provided for the first time, according to the NtMYC2a gene mutant plant capable of increasing the nicotine content of the tobacco leaves, the nicotine content of the tobacco leaves is increased by about 58% compared with that of a control group, the nicotine content of the tobacco leaves is remarkably increased, and the nicotine content of the tobacco leaves is increased. The production cost of nicotine raw materials is reduced.