To date, only a few algal species and essentially none of their viruses have been genetically manipulated due to inefficient genome editing methods. The development of heterologous gene expression tools in unicellular eukaryotic chlorella-like green algae introduces natural obstacles when studying the largely unexplored family of giant viruses that infect them, phycodnaviruses. These plaque-forming, dsDNA-containing viruses have large genomes some of them exceeding 500 kb with up to 600 protein-encoding genes and exist in aqueous environments throughout the world with titers as high as thousands of plaque-forming units per ml of indigenous water. Paramecium bursaria chlorella virus (PBCV-1), which infects Chlorella variabilis, is the type member of the genus Chlorovirus. We aim to establish a heterologous gene expression system in chlorella-chlorovirus counterparts using the CRISPR-Cas9 editing platform which will inevitably accelerate the exploration of this microalga and its viruses for a broader range of biotechnological applications, including but not limited to its use in producing biofuels by increasing lipid production or regulating destructive algal blooms.