Population genomics shows no distinction between pathogenic Candida krusei and environmental Pichia kudriavzevii: One species, four names

• DOI: 10.1371/journal.ppat.1007138
• Publication Date: 2018-07-19T18:43:49Z
• Authors: Alexander P. Doug...; Benjamin Offei; Stephanie Braun-G...; Aisling Y. Coughlan; Alexandre A. R. M...; Raúl A. Ortiz-Merino; Kevin P. Byrne; Kenneth H. Wolfe
• Keywords: Candida krusei

We investigated genomic diversity of a yeast species that is both an opportunistic pathogen and important industrial yeast. Under the name Candida krusei, it responsible for about 2% infections caused by in humans. Bloodstream with C. krusei are problematic because most isolates fluconazole-resistant. names Pichia kudriavzevii, Issatchenkia orientalis glycerinogenes, same yeast, including genetically modified strains, used industrial-scale production glycerol succinate. It also to make some fermented foods. Here, we sequenced type strains (CBS573T) P. kudriavzevii (CBS5147T), as well 30 other clinical environmental isolates. Our results show conclusively they species, collinear genomes 99.6% identical DNA sequence. Phylogenetic analysis SNPs does not segregate into separate clades, suggesting frequently acquired from environment. Reduced resistance fluconazole correlates presence one gene instead two at ABC11-ABC1 tandem locus. Most diploid, but one-quarter triploid. Loss heterozygosity common, mating-type PacBio/Illumina assembly 10.8 Mb CBS573T genome resolved 5 complete chromosomes, was annotated using RNAseq support. Each centromeres 35 kb desert containing large inverted repeat. This member genus family Pichiaceae (the methylotrophic yeasts clade), so only distantly related pathogenic species.