Evidence of Natural Hybridization in Brazilian Wild Lineages ofSaccharomyces cerevisiae

Abstract

The natural biology of Saccharomyces cerevisiae, the best known unicellular model eukaryote, remains poorly documented and understood although recent progress has started to change this situation. Studies carried out recently in the Northern Hemisphere revealed the existence of wild populations associated with oak trees in North America, Asia, and in the Mediterranean region. However, in spite of these advances, the global distribution of natural populations of S. cerevisiae, especially in regions were oaks and other members of the Fagaceae are absent, is not well understood. Here we investigate the occurrence of S. cerevisiae in Brazil, a tropical region where oaks and other Fagaceae are absent. We report a candidate natural habitat of S. cerevisiae in South America and, using whole-genome data, we uncover new lineages that appear to have as closest relatives the wild populations found in North America and Japan. A population structure analysis revealed the penetration of the wine genotype into the wild Brazilian population, a first observation of the impact of domesticated microbe lineages on the genetic structure of wild populations. Unexpectedly, the Brazilian population shows conspicuous evidence of hybridization with an American population of Saccharomyces paradoxus. Introgressions from S. paradoxus were significantly enriched in genes encoding secondary active transmembrane transporters. We hypothesize that hybridization in tropical wild lineages may have facilitated the habitat transition accompanying the colonization of the tropical ecosystem.

European derivedSaccharomyces cerevisiaecolonisation of New Zealand vineyards aided by humans

“…(2016) recently reported novel S. cerevisiae lineages in Brazil that are related to Japanese and North American lineages, but the Brazilian populations also contain signals for mating and introgression with the wine/European group, as well as hybridisation and introgression with American S. paradoxus. This hybridisation and subsequent introgression conceivably provided novel genetic combinations better adapted to inhabit Brazilian native biomes.…”

“…However, there were no estimations regarding the timing of either the Brazil or cocoa and coffee strain movements (Barbosa et al . 2016; Ludlow et al . 2016).…”

“…2016) and novel linages in Brazil (Barbosa et al . 2016). One pattern consistently found in all studies to date is the close relatedness and short divergence time of a ‘wine/European’ group (Liti et al .…”

“…Similarly, the recently discovery of a novel lineage in Brazil shows it was formed in part by hybridisation of migrants from the European/wine group with endemic S. paradoxus , which presumably then facilitated the colonisation of native Brazilian trees (Barbosa et al . 2016); it also seems reasonable to infer that humans facilitated this radiation event.…”

Morphophysiological and molecular characterization of wild yeast isolates from industrial ethanol process

“…Even under controlled process conditions, in which the domesticated yeasts are more prevalent, recent comparative genomic studies have demonstrated cases of spoilage in ethanol plants where native yeast strains were found to indeed overlap those inoculated ones. These wild yeasts can be found in different matrices, from wine making-related environments to tree barks, fruits and even seawater (Duina et al, 2014;Barbosa et al, 2016).…”