Fuente: WIPO "tobacco agriculture" The invention discloses an application of a tobacco FLS gene to regulate and control metabolism of plant flavonoid, and application of an NtFLS1 synthetase gene and an NtFLS2 synthetase gene, whose nucleotide sequences are shown in sequence tables of SEQ ID NO:1 and SEQ ID NO:2, to regulate and control metabolism of plant flavonoid. When the function of the tobacco FLS gene is studied at an early stage, a strain, the FLS gene expression level of which is obviously inhibited, is found in a tobacco plant for transferring an FLS gene overexpression vector. In the invention, the phenomenon that metabolism of flavonoid is affected due to inhibition of expression of the tobacco FLS gene, and the foundation is laid for further studying metabolic pathways of tobacco flavonoid.