Characterization of the Hormone and Stress-Induced Expression of <Emphasis Type="Italic">FaRE</Emphasis>1 Retrotransposon Promoter in Strawberry

Retrotransposons are the most abundant mobile elements in the plant genome and seem to play an important role in genome reorganization induced by environmental challenges. Their success in this function depends on the ability of their promoters to regulate plant adaptation to biotic and abiotic stresses. In this study, the promoter region of FaRE1 was amplified in the strawberry genome, and promoter::GUS fusion was constructed. We produced transgenic strawberry plants carrying FaRE1 promoter::GUS-fusion genes, and monitored GUS reporter activity. Histochemical and fluorimetric GUS analysis these plants showed the characteristics of the FaRE1 promoter were activated by either hormones treatments with ABA, NAA, and 2,4-D or cold stress. In addition, we found the GUS reporter was activated in the leaves of transgenic strawberry plants using 5-azaC. These results suggest that the promoter of FaRE1 may act as different signal transduction pathways, allowing FaRE1 retrotransposon to be activated in response to multiples challenges.