Genotypic variation in Penicillium chysogenum from indoor environments

Area of Science:

• Mycology
• Population Genetics
• Environmental Microbiology

Background:

• Penicillium chrysogenum is a ubiquitous mold frequently found indoors.
• Understanding its population structure is crucial for managing indoor environments.

Purpose of the Study:

• To investigate the population genetics and phylogenetic relationships of Penicillium chrysogenum isolates from indoor environments.
• To determine the genetic diversity and clonal structure of P. chrysogenum in Wallaceburg, Ontario.

Main Methods:

• Multilocus genotyping using heteroduplex mobility assay on acetyl co-enzyme A synthase, beta-tubulin, thioredoxin reductase, and ITS regions.
• Phylogenetic analysis employing maximum parsimony on allele sequences.

Main Results:

• Five unique multilocus haplotypes were identified, indicating a strictly clonal population structure with no evidence of recombination.
• Phylogenetic analysis resolved three distinct lineages, with one dominant clade comprising over 90% of house isolates.
• A second clade included house isolates clustered with ex-type strains of P. chrysogenum and P. notatum.
• Penicillium chrysogenum was rarely detected in outdoor air samples.

Conclusions:

• The indoor population of Penicillium chrysogenum is genetically uniform and clonal, dominated by a single lineage.
• This suggests limited gene flow and potential specific adaptations to indoor environments.
• The rarity in outdoor air contrasts with its indoor prevalence, highlighting indoor sources or specific dispersal mechanisms.