Almeida et al., (2014) A Gondwanan imprint on global diversity and domestication of wine and cider yeast Saccharomyces uvarum
In a previous work from the same team of Professor Sampaio, they observed a sympatric relationship between Saccharomyces uvarum and S. eubayanus in association with Nothofagus species in Norwestern Patagonia (Libkind et al., 2011). This association prompted them to further study the global genetic diversity and phylogeography of S. uvarum. A set of 54 representative strains were selected for Illumnia sequencing, including isolates from South America and Australasia associated with Nothofagus, as well as Holarctic isolates (from North America, Europe and Far East Asia) mostly associated with oak trees but also from artificial environments as wine and cider. Based on the sequence of 129,096 high-quality polymorphic sites the phylogenetic relationship of these isolates was drawn, enabling the separation in 3 different clades, one including all Holarctic strains and a few South American, another one containing the remaining of the South American isolates and a last one with the Australasia populations. The latter had the higher divergence (4.4%). Most of the genetic diversity was found in the South American isolates (0.689 in 1.248, π x100) in contrast with the Holarctic isolates (0.141). To identify signals of domestication, the genomes were screened for introgressions from other Saccharomyces species. Interestingly none of the Southern Hemisphere isolates had signs of foreign DNA, on the other hand the European isolates possess S. cerevisiae, S. kudriavzevii and most notably S. eubayanus introgressions. Sequence comparison shows that S. kudriavzevii introgressions were acquired from European S. kudriavzevii populations. The S. eubayanus introgressions were the most prevalent and extensive and were 99.5% identical to the type strain of S. eubayanus CRUB 1568 and 99.9% with the S. eubayanus portion of the S. pastorianus genome of the strain Weihenstephan 34/70. These introgressions could have been acquired from S. pastorianus or possibly from a non-yet identified European population of S. eubayanus. Function-specific introgressions were identified, mostly including categories relevant for wine fermentation.
Relevance of the article:
This article represents the first geographic characterization of S. uvarum, demonstration the higher diversity in the Southern Hemisphere in association with Nothofagus species, suggesting that the species may be native from the Southern Hemisphere. The multiple introgressions found in the European isolates mainly from S. eubayanus present for the first time signs of domestication of S. uvarum.