Provided herein are exemplary vectors for transforming algal cells. In exemplary embodiments, the vector comprises a Violaxanthin-chlorophyll a binding protein (Vcp) promoter driving expression of an antibiotic resistance gene in an algal cell. Embodiments of the invention may be used to introduce a gene (or genes) into the alga Nannochloropsis, such that the gene(s) are expressed and functional. This unprecedented ability to transform Nannochloropsis with high efficiency makes possible new developments in phycology, aquaculture and biofuels applications.