Gene Delivery Technologies with Applications in Microalgal Genetic Engineering

Abstract

Microalgae and cyanobacteria are photosynthetic microbes that can be grown with the simple inputs of water, carbon dioxide, (sun)light, and trace elements. Their engineering holds the promise of tailored bio-molecule production using sustainable, environmentally friendly waste carbon inputs. Although algal engineering examples are beginning to show maturity, severe limitations remain in the transformation of multigene expression cassettes into model species and DNA delivery into non-model hosts. This review highlights common and emerging DNA delivery methods used for other organisms that may find future applications in algal engineering.

Keywords: DNA; cyanobacteria; microalgae; transformation.

Figure 1

Gene delivery technologies for microalgae engineering. Overview of several available transformation technologies which have been or could be applied to algal engineering. (1) and (2) Several carriers that can mediate transformation of a DNA, protein, or chemical cargo (left panel) MOF: metal-organic framework, CPP: Cell-penetrating peptide. (3) Algal species which transformation has been commonly employed are depicted on the upper right: C. reinhardtii, Nannochloropsis sp., and P. tricornutum, including various cyanobacteria and other algal species as described in the manuscript. (4) Classical transformation methods are presented in the bottom left panel. (5) Process of transformation mediated by different DNA carriers and their interaction with the cell for delivery of the respective cargo. (5A) MOF-DNA, (5A1) recognition and cell uptake by endocytosis, (5A2) internalization and fusion with phagolysosome, 3 phagolysosome escape, 4 transport to nucleus, chloroplast or mitochondria; (5B) Liposome-DNA, (5B1) lyposome integration with cell membrane, (5B2) cargo (DNA or protein) exposed in cytoplasm and potential enzymatic degradation, 3 intact cargo transport to nucleus, mitochondria or chloroplast; (5C) Polymer-DNA, (5C1) cell recognition of polymer nanoparticle, charge interaction and cell uptake by endocytosis, (5C2) internalization and fusion with phagolysosome, (5C3) phagolysosome escape, (5C4) transport to nucleus, chloroplast or mitochondria; (5D) CPP-DNA, 1 cell recognition of CPP, by charge interaction (5D1a) or receptor recognition (5D1b) and cell uptake by endocytosis, (5D2) internalization and fusion with phagolysosome, (5D3) phagolysosome escape, (5D4) Transport to nucleus, chloroplast or mitochondria. Created with BioRender.com.