Classification of terverticillate penicillia based on profiles of mycotoxins and other secondary metabolites

Abstract

Strains of available terverticillate penicillium species and varieties were analyzed for profiles of known mycotoxins and other secondary metabolites produced on Czapek yeast autolysate agar (intracellular metabolites) and yeast extract-sucrose agar (extracellular metabolites) by using simple thin-layer chromatography screening techniques. These strains (2,473 in all) could be classified into 29 groups based on profiles of secondary metabolites. Most of these profiles of secondary metabolites were distinct, containing several biosynthetically different mycotoxins and unknown metabolites characterized by distinct colors and retardation factors on thin-layer chromatography plates. Some species (P. italicum and P. atramentosum) only produced one or two metabolites by the simple screening methods. The 29 groups based on profiles of secondary metabolites were known species or subgroups thereof. These species and subgroups were independently identifiable by using morphological and physiological criteria. The species accepted, the number of isolates in each species investigated, and the mycotoxins they produced were: P. atramentosum, 4; P. aurantiogriseum, 510 (group I: penicillic acid and S-toxin and group II: penicillic acid, penitrem A [low frequency], terrestric acid [low frequency], viomellein, and xanthomegnin); P. brevicompactum, 81 (brevianamid A and mycophenolic acid); P. camembertii group I, 38, and group II, 114 (cyclopiazonic acid); P. chrysogenum, 87 (penicillin, roquefortine C, and PR-toxin); P. claviforme, 4 (patulin and roquefortine C); P. clavigerum, 4 (penitrem A); P. concentricum group I, 10 (griseofulvin and roquefortine C), and group II, 3 (patulin and roquefortine C); P. crustosum, 123 (penitrem A, roquefortine C, and terrestric acid); P. echinulatum, 13; P. expansum, 91 (citrinin, patulin, and roquefortine C); P. granulatum, 6 (patulin, penitrem A, and roquefortine C [traces]); P. griseofulvum, 21 (cyclopiazonic acid, griseofulvin, patulin, and roquefortine C); P. hirsutum, 100 (group I: terrestric acid; group II: citrinin, penicillic acid , roquefortine C, and terrestric acid; and group III: roquefortine C and terrestric acid), P. hirsutum group IV, 2 (chaetoglobosin C); P. isariiforme, 1; P. italicum, 41; P. mali, 104; P. roquefortii, 78 (group I: mycophenolic acid, PR-toxin, and roquefortine C and group II: mycophenolic acid, patulin, penicillic acid [low frequency], and roquefortine C); P. viridicatum group I, 634 (brevianamid A [low frequency], penicillic acid, viomellein, and xanthomegnin), P. viridicatum group II and III, 494 (citrinin and ochratoxin A), P. viridicatum group IV, 12 (griseofulvin and viridicatumtoxin). It is proposed that profiles of secondary metabolites be strongly emphasized in any future revision of the penicillia.