Fecha de publicación: 18/12/2020 Fuente: Wipo Tobacco Agriculture The invention relates to a method for increasing the leaf number and the biomass of tobacco by utilizing a tobacco cytochrome C gene NtCYP94B3s. The nucleotide sequence of the tobacco cytochrome C gene NtCYP94B3s is shown as SEQ ID NO:1 in a sequence table. The method comprises the following steps of: firstly, constructing a plant RNAi vector, then, identifying agrobacterium tumefaciens-mediated tobacco transformation and transgenic plants, then, extracting the total RNA of wild plants and 25 pHellsgate12-transformed RNA gene T0-generation plants, performing Real time-PCR analysis with reference genes of 26s, analyzing expression conditions of different strains, and selecting two plants with the lowest expression quantity. According to the method in the invention, inhibition of the expression of the tobacco endogenous gene NtCYP94B3s in tobacco plants can obviously improve the leaf number and the biomass of the tobacco. The method has a wide application prospect and huge economic benefit potential.