Transformants of the fungus Knufia petricola. A gene for the synthesis of the black pigment melanin is mutated in the pink colonies.
Source: BAM
Material surfaces, especially those exposed to the weather, are readily colonized, and modified by microorganisms. One component of these biofilms are black fungi, which exhibit increased stress tolerance due to physiological and morphological adaptations. To investigate the interactions of the fungi with the materials, molecular biological methods are required that can be applied to the resilient organisms.
The development of CRISPR/Cas9 – often referred to as genetic scissors – has revolutionized the field of biology. As a component of the bacterial defense system against viruses, Cas9 cuts a DNA sequence to which it has been programmed by a short RNA sequence. When used as a genetic engineering tool in other organisms, the specifically inserted double-strand break in the genome is closed by the DNA repair systems of the cell. Desired recombination events (mutation, deletion, insertion) can be induced by the addition of recombinant DNA sequences.
Due to the efficiency of the adapted method – the components must be introduced into the cell and be functionally present there – the genomes of material-colonizing fungi can now also be modified in a targeted manner to elucidate the mechanisms of colonization and damage of material surfaces. Strains with desired properties can be generated and tested, such as those that lack the black pigment melanin or strains that produce fluorescent proteins for detection methods.
The review article was written at the invitation of the editors of the special issue of Biologie unserer Zeit “CRISPR-Cas9...more than just defense”, which was published as part of the DFG Priority Program SPP2141 at the end of 2024 and was funded by the subproject “CRISPR-Whisper – Project to raise public awareness”. The journal is aimed at researchers and students from all areas of biology, as well as teachers and interested laypersons. The article introduces the special features of rock-inhabiting fungi and the issues that need to be considered for genetically modifying fungi. Several examples illustrate how the adapted method can be used to edit the genome of the rock-inhabiting fungus Knufia petricola.
CRISPR-Cas9 in der Materialforschung: Den gesteinsbesiedelnden Pilzen auf der Spur
Schumacher, Julia, Biologie in Unserer Zeit, 2024