Research Features

Penicillium is one of the most economically important fungal genera. Directly or indirectly, every human has been affected by Penicillium. The 484 currently accepted species play important roles in nature as biodegraders, devastating agents of rots and as pre- and post-harvest pathogens on food crops. Some species produce regulated mycotoxins such as  patulin or ochratoxin that affects the apple and wheat industries, respectively. But on the positive side, species are used as starter cultures to produce speciality foods like cheese and fermented sausages. Various species also produce enzymes and secondary metabolites (or extrolites) that are important for biotechnological processes and it should not be forgotten, that the discovery of penicillin produced by Penicillium rubens revolutionized human health in proving an effective treatment for bacterial diseases.

A survey of Penicillium occurring in the diverse fynbos biome of South Africa was undertaken in 2009. This formed part of FABI researcher Prof. Cobus Visagie’s PhD study, conducted under the primary supervision of Prof. Karin Jacobs at Stellenbosch University. The survey involved collecting samples of air and soil as well as mites and the flower heads (infructescences) of Protea repens. This resulted in the isolation of ±1700 Penicillium strains isolated. Based on a consilient concept of species, these strains were found to represent 61 species of which 29 were new to science.

The newly discovered species were systematically described in several papers focused on the Sections that are applied to classify Penicillium species. These novel species belonged to sections Aspergilloides, Citrina, Excilicaulis, Lanata-Divaricata, Sclerotiora, Torulomyces and now Canescentia, and their description commonly resulted in revised taxonomies. Penicillium section Canescentia species have a worldwide distribution. They typically occur in soil and on plant debris and are very common in the fynbos biome of South Africa’s Western Cape Province. Chemically, these species are very active and they have consequently attracted substantial interest with several genomes having been generated in the past few years and subsequently explored for the production of novel chemical compounds.

Before this paper, species identifications in Section Canescentia were problematic. In Prof. Visagie’s latest paper, efforts were focused on simplifying species identifications, the description of five new species and provided an extensive review of secondary metabolites produced by Section Canescentia species. New species were named for South African mycologists who had worked and published on Penicillium. They include Dr Nicky Allsopp (P. allsoppiae), Dr Ethel Mary Doidge (P. doidgeae), Prof. Albert Eicker (P. eickerii), Dr Illtyd Buller Pole-Evans (P. pole-evansii) and Dr De Buys Scott (P. scottii). To read more, follow this link.

What became apparently clear in producing this final paper in a series treating Pencillium species from the fynbos and covering more than a decade of work on this topic, is that South Africa represents a diversity hotspot for Penicillium. The 29 new fynbos species emerging from this series of studies were isolated from samples collected at only three fynbos locations. With the fynbos being notoriously diverse and heterogenous, it is reasonable to expect that many more new species will be found as surveys consider soil and plant species from different regions. And these studies in the fynbos are only a start as surveys are extended to include other biologically diverse areas of South Africa.