Fuente: WIPO "tobacco agriculture" The invention discloses a tobacco nicotine content regulation gene IAA27 and a cloning method and application thereof. The nucleotide sequence of the tobacco nicotine content regulation gene IAA27 isshown in SEQ ID NO: 1; The amino acid sequence of the encoding protein is shown in SEQ ID NO: 2. The cloning method comprises synthesizing tobacco leaf cDNA, extracting total RNA from tobacco leaf, and reversing transcribing to obtain first strand cDNA; performing PCR amplification of IAA27 gene; designing primers according to the IAA27 gene sequence, with the tobacco leaf cDNA being adopted as atemplate; performing PCR amplification; recovering and purifying a PCR amplification product; and sequencing the product. The tobacco nicotine content regulating gene IAA27 is used for obtaining transgenic tobacco plants with high nicotine content. Inhibition of the expression of IAA27 gene in tobacco plants can obviously improve the nicotine content in tobacco leaves, and has wide application prospect in actual production.