Fuente: WIPO "tobacco agriculture" The invention discloses a tobacco nicotine content regulation gene NtCLC-b. The gene is capable of encoding a polypeptide for regulating the tobacco nicotine content. An amino acid sequence contained in the polypeptide is shown as SEQ ID: No.2; a nucleotide sequence contained in the tobacco nicotine content regulation gene NtCLC-b is shown as SEQ ID: No.1. The invention further discloses a cloning method and application of the regulation gene NtCLC-b. Due to over-expression of the gene NtCLC-b in tobacco plants, the content of nicotine in tobacco can be obviously reduced, and the tobacco nicotine content regulation gene has wide application prospects in actual production.