A novel technique for recombinant protein expression in duckweed (Spirodela polyrhiza) turions

Spirodela polyrhiza belongs to the family Lemnaceae, small aquatic plants that offer an alternative plant-based system for the expression of recombinant proteins. However, no turion transformation protocol has yet been established in this species. In this study, we exploited a pB7YWG2 vector harboring the eYFP gene that encodes enhanced yellow fluorescent protein (eYFP), which has been extensively used as a reporter marker for the visualization of the recombinant protein localization in plants. Agrobacterium tumefaciens-mediated turion transformation via vacuum infiltration was adopted to deliver the eYFP gene to turions, special vegetative forms of duckweeds produced for enduring harsh conditions. Transgenic turions were able to regenerate several duckweed fronds that exhibit yellow fluorescent emissions under a fluorescence microscope. The expression of the eYFP protein was subsequently verified via western blotting. To the best of our knowledge, this paper is the first to report an efficient protocol for generating transgenic S. polyrhiza expressing eYFP via Agrobacterium tumefaciens-mediated turion transformation. The ability of turions to withstand harsh conditions will favor the portability and versatility of transgenic duckweeds for further development of therapeutic compounds in plants.