Abstract: DNA methylation plays an important role in plant growth, organ differentiation and other biological processes. In this study, the function of DDM1 gene for forest strawberry was preliminarily investigated by constructing RNA interference(RNAi) expression vector. cDNA of forest strawberry was used as template, the forward fragment DDM1-1 and the reverse fragment DDM1-2 were cloned, and then they were respectively connected to interference expression vectors containing introns to construct RNAi expression vectors; it was transferred into Agrobacterium tumefaciens EHA105 receptor cells by freeze-thaw method, leaf disc method was used for genetic transformation of forest strawberry, and Gus staining was used to screen the positive seedlings; the phenotypic observation and expression analysis of transgenic strawberry plants were carried out. The results showed that the expression level of FveDDM1 gene in RNAi transgenic plants was lower than that in control plants, and the leaves showed obvious deformities, with narrowed leaf margins and deeper nicks. The results of this study can provide a basis for further exploration of the function and methylation of DDM1 gene on plant leaf growth and development.

Key words: DNA methylation, forest strawberry, RNAi, strawberry genetic transformation