Penicillium subgenus Penicillium - A guide to identification of food and air-borne terverticillate Penicillia and their mycotoxins

Species in Penicillium subgenus Penicillium have terverticillate penicilli and are related to the ascomycete genus Eupenicillium series Crustacea, Many of its species are very common, being associated with stored foods of human beings and other animals, but also with animal dung and building materials, indoor air, and several other habitats. The taxonomy of this group has been regarded to be especially difficult, but here we propose a stable taxonomy of these species based on a polyphasic study of a large number of isolates. 58 species are accepted. Four new species, P. cavernicola, P. freii, P. marinum and P. thymicola are described and two new combinations are made: P. melanoconidium and P. neoechinulatum. The species are ordered in natural sections and series, i.e. series that are both ecologically and phylogenetically consistent. The sections are named Coronata, Chrysogena, Roqueforti, Expansa, Digitata and Viridicata and emended because they differ considerably from the circumscriptions made by Pitt (1979). Some species with terverticillate penicilli, or rather twice biverticillate penicilli, including P. arenicola, P. scabrosum, P. fennelliae and P. lanosum, are regarded as phylogenetically and phenetically unrelated soil-borne forms and are not treated here. The phenotypic characters used include microand macro-morphology, physiology, including growth at 5, 15, 25, 30, 37oC, growth at 5 % NaCl and 15 % sucrose, and growth inhibition in presence of 1 % propionic acid, nutritional characters, including growth on urea, nitrite and creatine. All species have been analyzed for secondary metabolites (extrolites) and the profiles of these extrolites are highly species specific, and often of high consistency. In general features based on fungal differentiation (morphology and extrolites) are most diagnostic and consistent, but the classification proposed is also supported by the physiological and nutritional characters. The ecology and biogeography of the species is discussed and data on extrolites, both mycotoxins and pharmaceutically active compounds, is listed. Descriptions and colour illustrations of the colonies and micromorphology of the 58 accepted species are given. Keys to the taxa in the various series are given, but for a more detailed electronic database including partial beta tubulin sequences reference is made to http: //www.cbs.knaw.nl/ penicillium.htm.