Different species can find convergent solutions to adapt their genome to the same evolutionary constraints, although functional convergence promoted by chromosomal rearrangements in different species has not previously been found. In this work, we discovered that two domesticated yeast species, Saccharomyces cerevisiae, and Saccharomyces uvarum, acquired chromosomal rearrangements to convergently adapt to the presence of sulfite in fermentation environments. We found two new heterologous chromosomal translocations in fermentative strains of S. uvarum at the SSU1 locus, involved in sulfite resistance, an antimicrobial additive widely used in food production. These are convergent events that share similarities with other SSU1 locus chromosomal translocations previously described in domesticated S. cerevisiae strains. In S. uvarum, the newly described VII^XVI and XI^XVI chromosomal translocations generate an overexpression of the SSU1 gene and confer increased sulfite resistance. This study highlights the relevance of chromosomal rearrangements to promote the adaptation of yeast to anthropic environments.

Diverse species-specific karyotypes have been reported within Zephyranthes Herb., as well as different basic chromosome numbers (x = 5, 6, 7, and 9), with x = 6 being the most common. The aim of this work was to analyze the constitutive heterochromatin (C-Het) pattern of karyotypes in four diploid Zephyranthes species. For this purpose, a cytomolecular analysis of the karyotypes of Z. andalgalensis (2n = 2x = 12 = 4 m + 2 sm), Z. chacoensis (2n = 2x = 12 = 3 m + 2 sm + 1 st), Z. robusta (2n = 2x = 12 = 3 m + 2 sm + 1 st), and Z. pedunculosa (2n = 2x = 14 = 1 m + 3 sm + 3 st) was performed for the first time. All the species analyzed showed CMA+ terminal bands that could be distinguished by their heterochromatin pattern. Interestingly, DAPI+ interstitial bands were also found in the karyotype of Z. robusta. The four Zephyranthes C-Het patterns analyzed show that diploid species have little GC-rich heterochromatin, which is generally associated with terminal satellites, and that AT-rich heterochromatin is rare. The dysploidy evolutionary change between two basic chromosome numbers (x = 6 and 7) is discussed in the present study.

Torulaspora delbrueckii is a promising non-Saccharomyces yeast for beverage diversification, although its diversity and application in cider production remain poorly explored. This study characterized Patagonian T. delbrueckii isolates from wine- and cider-associated environments and evaluated their fermentative potential in apple must. Mitochondrial DNA-RFLP analysis showed that mitochondrial profiles varied according to the isolation source, while physiological characterization revealed differences in temperature, sulfite, and ethanol responses among isolates from different sources. Compared with wine isolates, cider isolates generally exhibited greater tolerance to high temperatures, lower sulfite tolerance, and shorter lag phases under ethanol stress. Eleven representative strains completed apple must microfermentations. Compared with a commercial Saccharomyces cerevisiae strain, T. delbrueckii produced higher glycerol and erythritol concentrations while achieving comparable or higher ethanol levels. Two contrasting strains were further evaluated in sequential mixed fermentations with S. cerevisiae. NPCC1340 enhanced glycerol and erythritol production, whereas NPCC1608 increased malic and succinic acids while maintaining low acetic acid levels. In mixed fermentations, ciders retained the characteristic metabolic profiles of each T. delbrueckii strain, whereas S. cerevisiae improved fermentation performance, producing intermediate fermentation kinetics. These findings reveal phenotypic diversity among Patagonian T. delbrueckii strains and suggest differences associated with their isolation sources, highlighting their potential as starter cultures for producing ciders with distinct chemical characteristics.