Penicillium setosum, a new species from Withania somnifera (L.) Dunal

Medicinal plants are considered as sources of novel and unexplored groups of endophytic microorganisms. A study on endophytic fungal species from the medicinal plant Withania somnifera (L.) Dunal resulted in the isolation of a Penicillium isolate (WSR 62) with antibiotic activity. Phylogenetic analysis showed that the isolate belongs to section Lanata-divaricata, and it is most closely related to P. javanicum. Subsequent detailed phylogenetic analyses using partial β-tubulin (BenA), calmodulin (CaM) and DNA-dependent RNA polymerase II (RPB2) gene sequences of a larger number of related strains revealed the distinctiveness of the isolate in the P. javanicum-clade. The isolate grows fast on Czapek yeast autolysate agar (CYA) and malt extract agar (MEA) incubated at 25°C, 30°C and 37°C. The obverse colony colour is dominated by the conspicuous production of cleistothecia and is greyish yellow on CYA and yellowish brown on MEA. Production of cleistothecia containing prominent spinose ascospores was present on all tested agar media. Based on the phylogenetic analysis and the phenotypic characterisation, strain WSR 62 from Withania is described here as a novel species named Penicillium setosum.