Revisiting the pink‐red pigmented basidiomycete mirror yeast of the phyllosphere

• Published in: MicrobiologyOpen (Weinheim) Vol. 5; no. 5; pp. 846 - 855
• Main Authors: Cobban, Alec, Edgcomb, Virginia P., Burgaud, Gaëtan, Repeta, Daniel, Leadbetter, Edward R.
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.10.2016; John Wiley and Sons Inc
• Subjects: Ballistospore; Base Sequence; Basidiomycetes; Basidiomycota - classification; Basidiomycota - genetics; Basidiomycota - isolation & purification; Basidiomycota - physiology; Cold Temperature; D1/D2; Deciduous trees; Desiccation; Domains; Drying; Freeze-thaw; Freezing; Gene sequencing; Genes; High temperature; Investigations; Leaves; Microorganisms; Morphology; Original Research; Pectin; Phyllosphere; Phylogenetics; Phylogeny; Physiology; Plant Leaves - microbiology; Polymerase Chain Reaction; Ribonucleic acid; RNA; RNA, Fungal - genetics; RNA, Ribosomal, 5S - genetics; rRNA; Sequence Analysis, RNA; Sporobolomyces; Taxonomy; Temperature tolerance; Thawing; Trees - microbiology; Vermont; Washington; Yeast; Yeasts; Vermont; United States > US; physiology; phylogeny; Ballistospore; D1/D2; rRNA; Sporobolomyces
• ISSN: 2045-8827; 2045-8827
• DOI: 10.1002/mbo3.374

By taking advantage of the ballistoconidium‐forming capabilities of members of the genus Sporobolomyces, we recovered ten isolates from deciduous tree leaves collected from Vermont and Washington, USA. Analysis of the small subunit ribosomal RNA gene and the D1/D2 domain of the large subunit ribosomal RNA gene indicate that all isolates are closely related. Further analysis of their physiological attributes shows that all were similarly pigmented yeasts capable of growth under aerobic and microaerophilic conditions, all were tolerant of repeated freezing and thawing, minimally tolerant to elevated temperature and desiccation, and capable of growth in liquid or on solid media containing pectin or galacturonic acid. The scientific literature on ballistoconidium‐forming yeasts indicates that they are a polyphyletic group. Isolates of Sporobolomyces from two geographically separated sites show almost identical phenotypic and physiological characteristics and a monophyly with a broad group of differently named Sporobolomyces/Sporidiobolus species based on both small subunit ribosomal RNA (SSU rRNA) and D1/D2 domains of the LSU rRNA gene sequences. Ten isolates of the ballistoconidium‐forming genus Sporobolomyces were recovered from leaf samples, seven from the eastern and three from the western coasts of the United States, to explore similarities in phylogeny and physiology within this polyphyletic genus. All isolates were similarly pigmented, capable of growth under aerobic and microaerophilic conditions, tolerant of freeze/thaw cycles, and moderately tolerant to desiccation and elevated temperatures. Phylogenies based on the D1/D2 region of the large subunit ribosomal RNA and on small subunit ribosomal RNA show these isolates to be closely related, suggesting the importance of future investigation of the taxonomy and shared characteristics of Sporobolomyces and its closest relatives.