Provided is a method for synthesizing a flavonoid compound. The method comprises providing a recombinant prokaryotic cell, wherein, in the prokaryotic cell, the transmembrane protein rhodanese Ygap of Escherichia coli is up-regulated or a target gene or target gene combination selected from the following groups is down-regulated: pyrB, accC, accB, purC, glyA, tktA, fabB, leuD, leuC, glpC, folK and leuA. Also provided are a prokaryotic cell for synthesizing a flavonoid compound and the use thereof, and the use of a kit and a regulation and control reagent. The present disclosure achieves significant improvement in the yield of the flavonoid compound.

Provided is: a transgenic plant that has a modified flower color; a self- or cross-fertilized descendant of the transgenic plant; or a propagule, a portion of a plant body, tissue, or cells from the transgenic plant or the self- or cross-fertilized descendant of the transgenic plant. The present invention causes both anthocyanin delphinidin and a flavone C-glycoside that is methylated at the hydroxyl group at the 7 position to be present in the cells of a plant.