Brettanomyces bruxellensis wine isolates show high geographical dispersal and long remanence in cellars

Brettanomyces bruxellensis is the main wine spoiler yeast all over the world, yet the structuration of the populations associated with winemaking remains elusive. In this work, we considered 1411 wine isolates from 21 countries that were genotyped using twelve microsatellite markers. We confirmed that B. bruxellensis isolates from wine environments show high genetic diversity, with 58 and 42% of triploid and diploid individuals respectively distributed in 5 main genetic groups. The distribution in the genetic groups varied greatly depending on the country and/or the wine-producing region. However, the two wine triploid groups showing sulfite resistance/tolerance were identified in almost all regions/countries. Genetically identical isolates were also identified. The analysis of these clone groups revealed that a given genotype could be isolated repeatedly in the same winery over decades, demonstrating unsuspected remanence ability. Besides cellar residency, a great geographic dispersal was also evidenced, with some genotypes isolated in wines from different continents. Finally, the study of old isolates and/or isolates from old vintages revealed that only the diploid groups were identified prior 1990 vintages. The triploid groups were identified in subsequent vintages, and their proportion has increased steadily these last decades, suggesting adaptation to winemaking practices such as sulfite use. A possible evolutionary scenario explaining these results is discussed.

The emergence of the genus Homo

This chapter’s focus is the emergence of the genus Homo in the Pliocene, proposing Homo habilis as the oldest species. The features of the H. habilis taxon are examined by means of the specimens from Olduvai and Koobi Fora. Next, the presence is considered of other early Homo taxa in the Rift (H. rudolfensis), South Africa (H. gautengensis and H. naledi), and, outside Africa, in Georgia (H. georgicus). The last part of the chapter investigates the phylogenetic relationships between the australopithecines and the earliest exemplars of Homo; the disappearance of Homo’s monophyly if the early specimens (before H. erectus) are included in the taxon; and the geographic dispersal of hominin populations during the Pliocene. Interpreting the evolutionary process of Pliocene hominins is necessary not only to consider the named genera and species, and the age of available specimens, but also to consider their geographic location.