The present application belongs to the technical field of
genetic engineering, and particularly relates to a
methyltransferase gene CmCMT2 and CmDRM2 application in regulating chrysanthemum flowering. The present application constructs an RNAi silencing
expression vector by isolating CmCMT2 and CmDRM2 genes in a chrysanthemum variety "Jinma", and obtains CmCMT2 -RNAi and CmDRM2 -RNAi transgenic "Jinma" plants by using a genetic transformation method, then performs
phenotype observation and statistics on the transgenic plants, and explores CmCMT2 and CmDRM2 the mechanism of the genes affecting early flowering of chrysanthemum by using an
RNA-seq method. The CmCMT2 and CmDRM2 genes are cloned from the chrysanthemum variety "Jinma", and spatiotemporal
expression analysis shows that CmCMT2 and CmDRM2 the genes are highly expressed during the process of "Jinma" from
bud development to color change; and CmCMT2 and CmDRM2 the expression level in leaves gradually decreases during the growth and development of "Jinma". The research results show that CmCMT2 and CmDRM2 the content of GA1 is changed by negatively regulating the expression of CmG20ox2a and CmG20ox2b , so that the flowering period of chrysanthemum is advanced by 15 and 8 days, respectively.