Promoter of alfalfa HPPD gene as well as preparation method and application of promoter

The invention discloses a promoter of alfalfa HPPD gene as well as a preparation method and an application of the promoter. The gene sequence of the promoter is shown in SEQ NO: 1 in the sequence. The preparation method of the promoter comprises steps as follows: (1) acquiring genomic DNA; (2) designing specific primer; (3) performing a first PCR reaction; (4) performing a second PCR reaction; (5) performing a third PCR reaction; (6) performing electrophoresis on 5 mu l of each of first, second and third PRC reaction liquids with 1% agarose gel; (7) recovering clear electrophoretic bands through gel cutting, performing DNA sequencing on PCR products with SP3Primer as a primer; splicing sequences obtained through sequencing, and removing overlapped sequences to finally obtain a promoter sequence of the alfalfa HPPD gene. The promoter of the HPPD gene plays important roles in regulating light/dark reactions as well as multiple stress reactions of the gene and can be used as a promoter of stress response, particularly light control response.