Betula platyphylla cycloartenol synthase gene BPX3 and application for regulation and control of betula platyphylla triterpene content

The invention belongs to the betula platyphylla transgenic technology field, and concretely relates to a betula platyphylla cycloartenol synthase gene BPX3 and an application for regulation and control of a betula platyphylla triterpene content. The betula platyphylla cycloartenol synthase gene BPX3 is characterized in that by utilization of designed primers BPX3R and BPX3F (shown in the graph 2), the cDNA full-length sequence of the cycloartenol synthase gene is obtained from betula platyphylla plants through clone, the sequence is shown in the graph 1 and is named after BPX3 temporarily, and the graph 1 and the graph 2 are shown in the specification. Genetic transformation of betula platyphylla clone is carried out by RNAi carriers of the constructed BPX3 gene p121-N4 and through agrobacterium tumefaciens mediation leaf disc transformation and transgenic strains are obtained through screening. In transgenic betula platyphylla saplings Y-12 and B-6, BPX3 is inhibited, the relative expression levels of BPY and BPW genes are raised substantially. The contents of betulinic acid and oleanolic acid in the transgenic betula platyphylla plant callus are higher than that of wild types substantially, which shows that BPX3 gene RNAs are inhibited and synthesis andaccumulation of object triterpene products betulinic acid and oleanolic acid are promoted. The deveopment of the betula platyphylla cycloartenol synthase gene BPX3 lays a foundation for betula platyphylla triterpene substance metabolism approach genetic modification and biotechnology utilization. The betula platyphylla cycloartenol synthase gene BPX3 can be used in research of raising the betula platyphylla triterpene effective component content by the transgenic technology and industrialization, and has good application prospects.