Phylogeny of the yeast genera Hanseniaspora (anamorph Kloeckera), Dekkera (anamorph Brettanomyces), and Eeniella as inferred from partial 26S ribosomal DNA nucleotide sequences

This study investigated the phylogenetic relationships among three yeast genera—Hanseniaspora (anamorph Kloeckera), Dekkera (anamorph Brettanomyces), and Eeniella—by analyzing partial 26S ribosomal DNA sequences. Researchers sequenced approximately 600 nucleotides from type strains of multiple species within these genera and constructed phylogenetic trees using parsimony analysis with bootstrap evaluation. The results revealed that Eeniella is derived within the Dekkera/Brettanomyces clade rather than forming a distinct genus, leading to the recommendation that Eeniella be synonymized with Brettanomyces. In contrast, Hanseniaspora was found to be monophyletic and distinct from the Dekkera-Brettanomyces-Eeniella group. The analysis showed that Hanseniaspora comprises two subclades: one containing H. occidentalis, H. osmophila, and H. vineae, and another containing H. guilliermondii, H. uvarum, H. valbyensis, and Kloeckera lindneri. The phylogenetic data do not support the recent proposal to transfer three Hanseniaspora species to the genus Kloeckeraspora, suggesting that such reclassification would be inconsistent with molecular evidence.

Key findings

• Eeniella is phylogenetically derived within the genus Brettanomyces and should be considered a synonym of Brettanomyces, not a separate genus
• Hanseniaspora is monophyletic and distinctly separate from the Dekkera-Brettanomyces-Eeniella clade, despite sharing some morphological characteristics
• Bipolar budding in Eeniella is a homoplasic (convergent) character rather than a key taxonomic feature, as it evolved independently in different yeast lineages
• Hanseniaspora species form two distinct subclades with different biochemical and morphological characteristics, contradicting previous proposals to split the genus