Ecological structuring of yeasts associated with trees around Hamilton, Ontario, Canada

Abstract

This study seeks to determine the distribution and diversity of yeasts in and around the Hamilton area in Canada. In light of the increasing number of fungal infections along with rising morbidity and mortality rates, especially among the immunocompromised, understanding the diversity and distribution of yeasts in natural environments close to human habitations has become an increasingly relevant topic. In this study, we analyzed 1110 samples obtained from the hollows of trees, shrubs and avian droppings at 8 geographical sites in and around Hamilton, Ontario, Canada. A total of 88 positive yeast strains were isolated and identified belonging to 20 yeast species. Despite the relative proximity of the sampling sites, our DNA fingerprinting results showed that the yeast populations were highly heterogenous. Among the 14 tree species sampled, cedar, cottonwood and basswood hollows had relatively high yeast colonization rates. Interestingly, Candida parapsilosis was isolated almost exclusively from Pine trees only. Our results are consistent with microgeographic and ecological differentiation of yeast species in and around an urban environment.

Exploring the northern limit of the distribution ofSaccharomyces cerevisiaeandSaccharomyces paradoxusin North America

“…These rates remain lower than Saccharomyces isolation success in British Columbia, Germany, Portugal (33% on Fagaceae and 9% on other trees; Sampaio & Goncalves, 2008) and Pennsylvania (23% on Fagaceae; Sniegowski et al, 2002), but are equivalent to what was observed in UK (8% on Fagaceae; Johnson et al, 2004) and Ontario (10% on Fagaceae and 4% on other trees; Maganti et al, 2012). These rates remain lower than Saccharomyces isolation success in British Columbia, Germany, Portugal (33% on Fagaceae and 9% on other trees; Sampaio & Goncalves, 2008) and Pennsylvania (23% on Fagaceae; Sniegowski et al, 2002), but are equivalent to what was observed in UK (8% on Fagaceae; Johnson et al, 2004) and Ontario (10% on Fagaceae and 4% on other trees; Maganti et al, 2012).…”

Local climatic adaptation in a widespread microorganism

“…In North America, S. paradoxus is sympatric with its sister species Saccharomyces cerevisiae, although S. cerevisiae seems to be less common or absent at higher latitudes [20,21], where temperatures are cooler (see electronic supplementary material, figure S2a,b). This distribution is in agreement with previous observations that S. paradoxus is able to grow at lower temperatures than its sister species [22][23][24][25][26].…”

Isolation and characterization of yeasts capable of efficient utilization of hemicellulosic hydrolyzate as the carbon source

“…Eleven of the isolated species formed a group with Candida lignohabitans. This yeast has been isolated from the gastrointestinal tract of insects of the order Coleoptera, and formed a group together with Candida shehatae and Sugiyamaella sp (Houseknecht et al, 2011), isolated from hollow portions of cotton stems (Maganti et al, 2012) and forest plants (Kurtzman, 2007). These authors have described the isolation of the species, while not commenting on its physiological characteristics or biotechnological applications.…”