Several species in Aspergillus section Nigri have been reported to produce sclerotia on well-known growth media, such as Czapek yeast autolysate (CYA) agar, with sclerotia considered to be an important prerequisite for sexual development. However Aspergillus niger sensu stricto has not been reported to produce sclerotia, and is thought to be a purely asexual organism. Here we report, for the first time, the production of sclerotia by certain strains of Aspergillus niger when grown on CYA agar with raisins, or on other fruits or on rice. Up to 11 apolar indoloterpenes of the aflavinine type were detected by liquid chromatography and diode array and mass spectrometric detection where sclerotia were formed, including 10,23dihydro-24,25-dehydroaflavinine. Sclerotium induction can thus be a way of inducing the production of new secondary metabolites from previously silent gene clusters. Cultivation of other species of the black aspergilli showed that raisins induced sclerotium formation by A. brasiliensis, A. floridensis A. ibericus, A. luchuensis, A. neoniger, A. trinidadensis and A. saccharolyticus for the first time.
Plos One, 2014, Vol 9, Issue 4
fruit; sclerotia formation; Fungi Plantae (Fungi, Microorganisms, Nonvascular Plants, Plants) - Fungi Imperfecti or Deuteromycetes  Nigri section Aspergillus brasiliensis species Aspergillus ibericus species Aspergillus luchuensis species Penicillium rubens species Aspergillus saccharolyticus species Aspergillus niger species sensu stricto Aspergillus floridensis species Aspergillus neoniger species Aspergillus trinidadensis species Aspergillus aculeatus species strain-IBT 21030 Aspergillus welwitchiae species; Monocotyledones Angiospermae Spermatophyta Plantae (Angiosperms, Monocots, Plants, Spermatophytes, Vascular Plants) - Gramineae  rice common; CYA agar; dihydro-24,25-dehydroaflavinine; gene cluster; raisin; 03502, Genetics - General; 03504, Genetics - Plant; Biochemistry and Molecular Biophysics; diode array detection laboratory techniques; liquid chromatography laboratory techniques, chromatographic techniques; mass spectrometry laboratory techniques, spectrum analysis techniques; Molecular Genetics; MULTIDISCIPLINARY; THAI COFFEE BEANS; SEXUAL REPRODUCTION; FUMONISIN B-2; ANTIINSECTAN METABOLITE; CRYPTIC SEXUALITY; TUBINGENSIN-A; OCHRATOXIN; MYCOTOXINS; GROWTH; FUNGI