Molds are able to reproduce sexually

Washington, Jan 9: For over 100 years, it was assumed that the penicillin-producing mould fungus Penicillium chrysogenum only reproduced asexually through spores.

But now, an international research team led by Prof. Dr. Ulrich Kuck and Julia Bohm from the Chair of General and Molecular Botany at the Ruhr-Universitat has now shown for the first time that the fungus also has a sexual cycle, i.e. two “genders”.

Through sexual reproduction of P. chrysogenum, the researchers generated fungal strains with new biotechnologically relevant properties – such as high penicillin production without the contaminating chrysogenin.

Not only animals and plants, but also many microorganisms such as fungi and algae can reproduce sexually.

The advantage: the progenies possess a combination of genes from both mating partners and thus have new properties. Sexual reproduction in fungi is, however, not the rule.

Most reproduce via spores which, in the case of moulds, occur as white, green or black deposits on spoiled food. These spores only bear the genes of one parent fungus.

“Five years ago we already detected the existence of so-called sex genes in Penicillium chrysogenum,” Prof. Kuck said.

Now, the researchers have discovered specific environmental conditions in which the fungus actually reproduces sexually.

The decisive thing was to breed fungal strains in the dark under oxygen deprivation conditions in a nutrient medium supplemented with the vitamin biotin.

The offspring exhibited new properties, both at the molecular level, as well as in their phenotypes.

Using so-called microarray analysis, the biologists also investigated the activity of all the approximately 12,000 genes of the mould fungus.

The result: the sex genes control the activity of biologically relevant genes, for example those for penicillin production.

The study is published in the journal in PNAS. (ANI)