High efficiency transformation by electroporation of the freshwater alga Nannochloropsis limnetica

AbstractThe microalgal genus ofNannochloropsis is considered one of the most promising organisms for the production of biofuels due to their high lipid content. Transformation systems for marineNannochloropsis species have been established in the recent decade, however, genetic manipulation ofNannochloropsis limnetica, the only known freshwater species in this genus, is not yet available. Based on established marineNannochloropsis species electrotransformation protocol, nuclear genetic transformation was established inN. limnetica, meanwhile the appropriate antibiotic selection concentration and electric field strength of electroporation were determined. For the selection of transformants inN. limnetica on plates, 0.07  μg mL−1 of zeocin or 5  μg mL−1 of hygromycin B was proved sufficient, and the transformation efficiency was<  2 × 10−8 with a single pulse ranging from 2200 to 2600  V using 2-mm electroporation cuvettes. Pretreatment ofN. limnetica with 10  mM lithium acetate and 3 mM dithiothreitol before electroporation increased transformation efficiency hundreds of times, and the highest transformation efficiency of 10–11 × 10−6 was obtained with an electric field strength of 12,000  V/cm. Our results help to expand the biotechnological applications of this freshwater species and provide means for successful electrotransformation of other microalgae as well.Graphic abstractHigh-efficiency transformation of freshwaterNannochloropsis ...
Source: World Journal of Microbiology and Biotechnology - Category: Microbiology Source Type: research