Molecular and biochemical taxonomic tools for the identification and classification of plant-pathogenic Penicillium species

Abstract

Five species of Penicillium (Penicillium chrysogenum, P. funiculosum, P. griseofulvum, P. implicatum and P. oxalicum) are implicated in seed-borne diseases. Here, we report the discovery of molecular markers based on the internal transcribed spacer regions of fungal ribosomal DNA (rDNA), which are described as primary DNA barcode markers of fungi, for rapid diagnosis and early detection of Penicillium spp. The present markers are expected to be useful for the prevention of seedling and systemic plant diseases associated with Penicillium spp. Our findings, which provide valuable insights into the taxonomy of Penicillium spp., should contribute to improve safety of agricultural produce, thereby protecting both humans and animals from harmful food contaminants such as mycotoxins. In addition, we examined the cellular fatty acid composition of five species of Penicillium. The species studied were found to possess similar fatty acid composition; however, they differed in terms of relative concentration. The principal fatty acids were oleic acid (C18:1) and linoleic acid (C18:2), comprising 80% or more of the total fatty acid composition of these species. These fatty acid profiles may be useful for characterization and identification of fungi. Data derived from the present study highlight the importance of using polyphasic methods for accurate species-level identification of Penicillium.