Investigations of polyporoid fungi of Tanzania: Taxonomy, transcriptomics and biochemical analyses of Kusaghiporia usambarensis and Piptoporellus baudonii

  • Date:
  • Location: Evolutionsbiologiskt centrum Ekmansalen, Zoom-link:
  • Doctoral student: Juma Mahmud Hussein
  • Organiser: IOB
  • Contact person: Juma Mahmud Hussein
  • Disputation

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Polyporoid fungi refers to basidiomycetes with fruiting bodies with the hymenium located to the inner surfaces of pores or narrow tubes. The majority of polyporoids belongs to Polyporales. Most Polyporales are saprobes, but some are plant pathogens. The overall aim of this thesis was to study the taxonomy, systematics and chemistry of the two species Kusaghiporia usambarensis (saprobic) and Piptoporellus baudonii (a plant pathogen) collected from Tanzania, using morphological and molecular approaches, combined with transcriptomics and pharmacognostic investigations.

The main contribution of this thesis includes the description a new genus with the new species K. usambarensis from the Usambara Mountains, Tanzania; investigation of the chemical composition of volatile compounds from this medicinal mushroom; isolation and structure determination of a novel and most abundant peptide in K. usambarensis, and further to elucidate the phylogenetic position of Piptoporellus baudonii (formerly known as Laetiporus baudonii) by using a four molecular markers dataset.

Paper I was conducted applying a classical taxonomic approach, including both morphological and phylogenetic analyses, to describe a new genus and species K. usambarensis. Paper II, investigated volatiles and volatile derivatives in dichloromethane extracts of K. usambarensis analysed by GC-MS and NMR spectroscopy. The main elements were phenols, and esters, compounds that may explain the formerly reported antioxidant activity and traditional medicinal use of the mushroom. In paper III, screening of peptides in K. usambarensis revealed a novel cysteine-rich peptide, highly expressed at gene level and the most abundant compound in the fruiting body. Combined LC-MS and transcriptome analyses were used to determine the peptide sequence, and subsequently NMR spectroscopy to determine the 3D structure of the novel peptide, kusaghitide. In paper IV molecular techniques were used to elucidate the phylogenetic position of the parasitic Laetiporus baudonii. Phylogenetic analyses of combined 5.8S, nrLSU, nrSSU, and TEF1 gene sequences placed L. baudonii in the genus Piptoporellus, hence the new combination Piptoporellus baudonii was proposed. This thesis has contributed to build capacity in the fields of mycology, systematics and pharmacognosy in order to reinforce ecological knowledge and ethnopharmaceutical research for future drug discovery in Tanzania and Africa at large.