Promoter P(PSP1–5)-BnPSP-1 From Ramie (Boehmeria nivea L. Gaud.) Can Drive Phloem-Specific GUS Expression in Arabidopsis thaliana

Isolation of phloem-specific promoters is one of the basic conditions for improving the fiber development and resistance of ramie phloem using genetic engineering. In this study, we isolated a ramie endogenous promoter (named P(PSP1)-BnPSP-1) and analyzed the function of its truncated fragments in Arabidopsis. The results show that P(PSP1)-BnPSP-1 can drive the GUS reporter gene to be specifically expressed in the veins of Arabidopsis. After hormone and simulated drought treatment of the independent Arabidopsis lines carrying P(PSP1)-BnPSP-1 and its truncated fragments, only P(PSP1–5)-BnPSP-1 (−600 to −1 bp region of P(PSP1)-BnPSP-1) is stably expressed and exhibits phloem specificity. Our findings suggest that P(PSP1–5)-BnPSP-1 can be used as a phloem specific promoter for further research.