Ana Raquel O Santos | PubMed Health

PubMed2026

Sungouiella purgamenti sp. nov., a yeast isolated from hospital wastewater in Brazil: a taxogenomic analysis.

Yeasts recovered from wastewater of a public hospital in Minas Gerais state, Brazil, included a single isolate representing a putative novel species. Sequence analysis of the ITS-5.8S region and the D1/D2 domains of the LSU rRNA gene placed this yeast within the genus Sungouiella, close to Sungouiella thailandica. Phylogenomic inference based on 1,849 single-copy orthologues from Sungouiella species with available genomes confirmed that strain UFMG-CM-Y7468 forms a distinct lineage with S. thailandica as its closest known relative. The name Sungouiella purgamenti sp. nov. (MycoBank MB 863665) is proposed, with CBS 19634 designated as the holotype. The isolate was able to grow at 37 °C, showed susceptibility to most antifungal agents tested, except for itraconazole with an MIC of 0.5 mg l-1, within the dose-dependent range, and exhibited strong extracellular protease activity. However, S. purgamenti showed a genomic toolkit consistent with a stress-tolerant and environmentally versatile lifestyle, while no specific or unique virulence determinants were identified based on genome content alone.

Brazil↗

PubMed2025

Taxogenomic analysis of Pichia senei sp. nov. and new insights into hybridization events in the Pichia cactophila species complex.

Three strains of a novel yeast species were isolated from necrotic cactus tissues of Cereus saddianus and Micranthocereus dolichospermaticus and from phytotelmata of Bromelia karatas. DNA sequence analysis of the Internal Transcribed Spacer (ITS) region and D1/D2 domains of the large subunit ribosomal RNA, along with whole genome phylogenomic analysis, showed that this yeast is most closely related to Pichia insulana, Pichia cactophila, and Pichia inconspicua. The new species differs by 10-13 nucleotide substitutions from these species in D1/D2 sequences and exhibits <90% genome-wide average nucleotide identity to them. The name Pichia senei sp. nov. is proposed for the novel species, which is homothallic and produces asci with one to four hat-shaped ascospores. The holotype is CBS 16311 (MycoBank MB 858723). Taxogenomic analyses of the P. cactophila species complex, including P. senei, provide new insights about the hybridizations events that shaped this group. Pichia insulana and P. inconspicua are identified as the parental lineages that originated P. cactophila, and P. senei also appears closely related to one of the progenitors of P. inconspicua. We assess phylogeny, heterozygosity, and ploidy to explore the processes shaping diversity, showing how genomic data support yeast species delimitation and reveal complex hybridization.

Phylogeny↗