Fungi are likely to contact mutagens when isolated from nature and in subsequent growth. These include antibiotics to control contaminants in isolation media and self produced mutagens (e.g. mycotoxins) when fungi grow. This affects DNA analysis by PCR, preserving wild type strains, and biodiversity estimates. It would be useful to have some ideas on how to avoid these mutagens.
I see the problem.Mutagenesis is one point, selection for special types of mitochondria by application of antibiotics is another one. Antibiotics might also select against those interesting isolates that harbour bacterial endobionts. In addition, for a geneticist, it is nearly never a good idea to work with heterokaryonts. The following procedure avoids extensive heterokaryon propagation.
Myself, I normally never used antibiotics for isolating fungal pure cultures. I normally followed this simple regime: 1. Inoculate the plates with as little material as possible (and reasonable). 2. Pick tiny pieces of mycelium from the front of the growing zone of those mycelia that interest you. 3. Let the resulting colonies sporulate (if they do) and plate the spores for single colonies from single spores. 4. Pick single colonies again, repeat sporulation cycles and repeat until you are convinced that you have a pure culture. 5. Always pick more than one (six is a good idea) independently isolated single colonies. Due to heterokaryotic starting conditions, they might be different. 6. Do not throw away the primary and all secondary plates, until you are through with the isolation procedure. Otherwise you might miss comlementary mating types, or colonies with different properties that might be due to different nuclei from primary herterokaryons.
Will this help?
Yes, there is useful information there that could be employed. I suppose it depends on which fungi one is working. I tend to focus on those that produce secondary metabolites and often penillicia, aspergilli and fusaria. There are of course many others. These metabolites are often mutagenic or have not been tested for this property and so might be. They are often produced in media in/on which the fungi are growing and then the culture is used for DNA analysis for example. Or the original strains are isolated from the environment on agar with antibiotics (i.e.mutagens) and grown on media in which mutagens are produced and then preserved as the wild type. So it does not make a lot of sense.
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