Establishment of a novel set of vectors for transformation of the dinoflagellate Amphidinium carterae

Peridinin-containing dinoflagellate algae have a chloroplast genome formed from plasmid-like minicircles. This fragmented genome has allowed us to develop a genetic modification methodology involving the use of biolistics to introduce artificial minicircles in Amphidinium carterae (Nimmo et al., 2019). The previously reported artificial minicircles were based on native minicircles containing either the psbA or atpB gene. Each artificial minicircle allowed expression of a single selectable marker instead of psbA or atpB. Here, we present two further artificial minicircles for use in transformation of A. carterae. One is based on the petD minicircle, allowing the expression of a single selectable marker. The second is based on the two-gene minicircle originally containing atpA and petB, and allows the dual expression of a selectable marker and a gene of interest. Our research suggest that all of the 20 or so minicircles in A. carterae are suitable for adaptation as artificial minicircles, allowing for the simultaneous introduction of multiple genes.