Magnetic nanoparticles mediate the transformation of antimicrobial peptides HeM into Chlorella ellipsoidea

Antimicrobial peptides are short peptides with broad-spectrum antimicrobial properties. Heliomicin, a peptide from Heliothis virescens, was re-engineered to have both antifungal and bacterial activities and renamed as HeM. Chlorella is a perfect bioreactor candidate due to fast growth, high photosynthetic efficiency, and easy large-scale culture. This study describes the successful transformation of HeM into Chlorella ellipsoidea F962. A binary expression vector pGcp4 was constructed that carried the antimicrobial peptide gene HeM and the gene encoding neomycin phosphotransferase II (NPT II). The pGcp4 was introduced into C. ellipsoidea F962 by magnetic nanoparticle-mediated transformation method. The positive transformants were obtained by G418 resistance screening. Molecular and genetic analyses on transformants revealed that the antimicrobial peptide gene and the NPT II gene had successfully entered C. ellipsoidea and expressed antimicrobial activity in transgenic cells. This method can provide a new way to produce transgenic Chlorella as well as explore wide utilization of Chlorella through magnetic transformation methods to mediate the production of antimicrobial peptides by C. ellipsoidea.