Fuente: WIPO "tobacco agriculture" The invention discloses a nicotine content controlling gene Ribosomal L4/ L1. The gene is used for coding polypeptide capable of controlling nicotine content in tobacco, wherein the amino acid sequence in the polypeptide is shown as SEQ ID: No.2; the nucleotide sequence in the nicotine content controlling gene Ribosomal L4/ L1 is shown as SEQ ID: No.1. The invention also discloses a cloning method and application of the controlling gene. The expression of the Ribosomal gene in the tobacco plant is inhibited, so that the nicotine content in the tobacco can be obviously decreased; the nicotine content controlling gene Ribosomal L4/ L1 has a good application prospect in actual production.