Current Status and Perspective on the Use of Viral-Based Vectors in Eukaryotic Microalgae

Abstract

During the last two decades, microalgae have attracted increasing interest, both commercially and scientifically. Commercial potential involves utilizing valuable natural compounds, including carotenoids, polysaccharides, and polyunsaturated fatty acids, which are widely applicable in food, biofuel, and pharmaceutical industries. Conversely, scientific potential focuses on bioreactors for producing recombinant proteins and developing viable technologies to significantly increase the yield and harvest periods. Here, viral-based vectors and transient expression strategies have significantly contributed to improving plant biotechnology. We present an updated outlook covering microalgal biotechnology for pharmaceutical application, transformation techniques for generating recombinant proteins, and genetic engineering tactics for viral-based vector construction. Challenges in industrial application are also discussed.

Microalgae‐made human vaccines and therapeutics: A decade of advances

“…The disadvantages are the cost of materials and specialized equipment. [32,45,46] Other less-used methods have also worked in microalgae. For example, mixing protoplast cells and plasmids with polyethylene glycol (PEG)-mediated transfer to transform Chlorella sp., [47] C. ellipsoidea, [48] and Pleurochrysis carterae.…”

“…To date, about 40 microalgal species have been genetically transformed for different purposes. [ 30,32 ] However, the most genetically engineered species is C. reinhardtti followed by D. salina , although other species have also been explored recurrently, such as Chlorella pyrenoidosa , Nannochloropsis sp., T. pseudonana , H. pluvialis , Volvox carteri , P. tricornutum , and Schizochytrium sp. [ 27,28,33,34 ]…”

“…To date, about 40 microalgal species have been genetically transformed for different purposes. [30,32] However, the most genetically engineered species is C. reinhardtti followed by D. salina, although other species have also been explored recurrently, such as Chlorella pyrenoidosa, Nannochloropsis sp., T. pseudonana, H. pluvialis, Volvox carteri, P. tricornutum, and Schizochytrium sp. [27,28,33,34] Microalgal nuclear, mitochondrial, and chloroplast genomes have been mostly modified by conventional delivery methods, including Agrobacterium-mediated transformation, [11,35] electroporation, [10,36] agitation with glass beads, [9,37] and biolistic or particle bombardment.…”

A potential paradigm in CRISPR/Cas systems delivery: at the crossroad of microalgal gene editing and algal-mediated nanoparticles

“…An ideal transformation strategy and delivery vector are required to transport foreign DNA into cells. Among the transformation methods, such as electroporation [ 42 ], glass beads [ 43 ], particle bombardment [ 44 ], and Agrobacterium tumefaciens -mediated transformation [ 45 ], electroporation is the preferred method for microalgae transformation because it is rapid and highly effective in the generation of transformants (approximately 0.4 ~ 3 × 10 3 transformants per µg of exogenous DNA) [ 42 , 46 ]. There are few delivery carriers in CRISPR systems, such as viral vectors [ 47 ], extracellular vehicles [ 48 ], cell-penetrating peptides [ 49 ], and etc.…”

An Algae-Made RBD from SARS-CoV-2 Is Immunogenic in Mice

“…Overall, stable transformation requires extensive characterization of the candidate clones to identify the most productive and stable ones, which is mainly due to the random insertion of the heterologous DNA into the genome. In contrast, the recently reported transient expression technologies offer rapid production and high yields by not requiring the characterization of clones (e.g., geminiviral vectors such as pAlgevir and BeYDV vectors) [ 25 , 26 , 27 ].…”