Comparative Analysis of Stress Adaptation in the Yeast Microbiome of Cactus

ABSTRACT

Together with other fungi, yeasts make up a significant component of the plant microbiome. As the planet warms, cacti expand their range. Cactus‐associated yeasts are known to exhibit signatures of adaptation to the cactus host. Our previous isolation of a wild Saccharomyces paradoxus yeast from a cactus in a forest of oaks populated by S. cerevisiae prompted us to further explore cactus‐associated fungi and look for genomic and phenotypic signatures of adaptation. Here we characterize seven yeast isolates, five from cacti and two from adjacent non‐cactus plants, among which was a novel species of Coniochaeta isolated from wild grape that we name C. udwismasis . Closely‐related isolates from distinct plant hosts exhibited distinct features, including differences in thermotolerance, freeze‐thaw tolerance, pigmentation, and predicted septin protein complex assembly, providing new insights into possible mechanisms of cactus adaptation by the yeast microbiome.