Sampling and yeast isolation
The sampling for this study took place in the Atacama Desert near the San Pedro de Atacama village (22° 55′ S, 68° 12′ W) in January 2021. The sampling strategy involved identifying tree species and collecting various samples from each tree. Briefly, 5 g of bark, bark-exuded gum, pods, and flowers of Algarrobo (Neltuma chilensis (Molina) C.E.Hughes & G.P.Lewis), Tamarugo (Strombocarpa tamarugo (Phil) C.E.Hughes & G.P.Lewis) and Chañar (Geoffroea decorticans were collected. A total of 22 samples were collected in aseptic conditions and transferred to tubes containing 10 mL of selective enrichment medium composed of YNB (Yeast Nitrogen Base) supplemented with 2% (w/v) glucose and 4% (v/v) ethanol. This medium was specifically designed to exclusively select for ethanol-tolerant yeast species (Villarreal et al. , 2022). The tubes were incubated at 25°C without agitation for a period of 14 days. After incubation, 100 µl aliquots were spread onto yeast-extract peptone dextrose (YPD) agar plates containing chloramphenicol (20 µg ml−1) and incubated at 25°C until yeast colonies emerged. Representative colonies of each distinct morphotype were purified through streak inoculation on YPD agar for further characterization. To ensure long-term preservation, yeast cultures were stored at -80°C in a broth culture supplemented with 20% (w/v) glycerol.