Sexual fungus could be the key to revolutionizing penicillin

Though penicillin was once a miracle cure for bacterial infections ranging from syphilis to staph, it is slowly becoming obsolete. Bacteria are evolving antibiotic resistance, and medicine is racing to keep up by producing new and different forms of the drug. Penicillin and its derivatives come from a fungus called Penicillium chrysogenum. It's been difficult for scientists to cultivate better strains of the fungus because it reproduces asexually — thus limiting its genetic diversity.

But now this is hope, and it comes directly from sex. A team of researchers have documented an experiment in which they induced sexual reproduction in P. chrysogenum. Having a sexual fungus would allow them to cross promising strains to create potentially new derivatives of penicillin in the war on antibiotic-resistant bacteria. The researchers have already produced new genetic traits in the offspring of the now-sexual mold. These are traits they say could help in the quest for new medicines.

In their paper, published this week in Proceedings of the National Academy of Sciences, the researchers write:

The species has been considered asexual for more than 100 years, and despite concerted efforts, it has not been possible to induce sexual reproduction, which has prevented sexual crosses being used for strain improvement. However, using knowledge of mating-type (MAT) gene organization, we now describe conditions under which a sexual cycle can be induced leading to production of meiotic ascospores. Evidence of recombination was obtained using both molecular and phenotypic markers. The identified heterothallic sexual cycle was used for strain development purposes, generating offspring with novel combinations of traits relevant to penicillin production.

Not only that, but the researchers speculate that this sexualization of fungus can be used in other "asexual fungi of economic importance," which means their breakthrough has broad applications. Also, in related news, the name of my new band is Asexual Fungi of Economic Relevance.

Read more about sexual fungus in PNAS.