Glass Bead-based Genetic Transformation:An Efficient Method for Transformation of Thraustochytrid Microorganisms

Here, we describe a new method for genetic transformation of thraustochytrids, well-known producers of polyunsaturated fatty acids (PUFAs) like docosahexaenoic acid, by combining mild glass (zirconia) bead treatment and electroporation. Because the cell wall is a barrier against transfer of exogenous DNA into cells, gentle vortexing of cells with glass beads was performed prior to electroporation for partial cell wall disruption. G418-resistant transformants of thraustochytrid cells (Aurantiochytrium limacinum strain SR21 and thraustochytrid strain 12B) were successfully obtained with good reproducibility. The method reported here is simpler than methods using enzymes to generate spheroplasts and may provide advantages for PUFA production by using genetically modified thraustochytrids.