Yeasts of the soil – obscure but precious

Abstract

Pioneering studies performed in the nineteenth century demonstrated that yeasts are present in below‐ground sources. Soils were regarded more as a reservoir for yeasts that reside in habitats above it. Later studies showed that yeast communities in soils are taxonomically diverse and different from those above‐ground. Soil yeasts possess extraordinary adaptations that allow them to survive in a wide range of environmental conditions. A few species are promising sources of yeast oils and have been used in agriculture as potential antagonists of soil‐borne plant pathogens or as plant growth promoters. Yeasts have been studied mainly in managed soils such as vineyards, orchards and agricultural fields, and to a lesser extent under forests and grasslands. Our knowledge of soil yeasts is further biased towards temperate and boreal forests, whereas data from Africa, the Americas and Asia are scarce. Although soil yeast communities are often species‐poor in a single sample, they are more diverse on the biotope level. Soil yeasts display pronounced endemism along with a surprisingly high proportion of currently unidentified species. However, like other soil inhabitants, yeasts are threatened by habitat alterations owing to anthropogenic activities such as agriculture, deforestation and urbanization. In view of the rapid decline of many natural habitats, the study of soil yeasts in undisturbed or low‐managed biotopes is extremely valuable. The purpose of this review is to encourage researchers, both biologists and soil scientists, to include soil yeasts in future studies.

Fungal evolution: major ecological adaptations and evolutionary transitions

“…The ecology of this group is very diverse. In addition to species associated with sugary substrates (Pozo, Herrera & Bazaga, ; Lievens et al, ), members of the Saccharomycetaceae have been found in soil (Treseder & Lennon, ; Yurkov, ), on plant surfaces (Boynton & Greig, ), in the gut of insects (Blackwell, ), on vertebrate skin (Underhill & Iliev, ; Limon, Skalski & Underhill, ), and in marine and frozen environments (Bass et al, ; Amaretti et al, ; Richards et al, ; Martorell et al, ; Rämä et al, ). Many have been isolated from industrial fermentations, including contaminants of food products and alcoholic fermentations (Hittinger, Steele & Ryder, ), sorbitol (Louis et al, ) and pure hydrocarbons (Buddie et al, ).…”

“…Yeasts can also be found in association with surfaces of both vertebrates and invertebrates (see Section V). Fungi with a yeast lifestyle can be found in virtually any soil type, and even though their abundance tends to be relatively low, their diversity is considerable (Treseder & Lennon, ; Tedersoo et al, ; Yurkov, ).…”

The ecology of killer yeasts: Interference competition in natural habitats

“…One of the biggest questions in ecology is how diversity is maintained in ecosystems (Hutchinson, 1959). As with biodiversity in general, yeast diversity is broad across nearly every imaginable ecosystem (Buzzini, Turchetti, & Yurkov, 2018;Carbonetto, Ramsayer, Nidelet, Legrand, & Sicard, 2018;Chappell & Fukami, 2018;Stefanini, 2018;Yurkov, 2018). The current understanding of killer yeasts' impacts on diversity is based mostly on mathematical models, and only a few hypothesis-driven observational studies have addressed killer yeasts' impacts on diversity in nature.…”

Quantifying the efficiency and biases of forest Saccharomyces sampling strategies

“…Saccharomyces yeasts are also a single clade in the diverse polyphyletic group of yeasts (singlecelled fungi that reproduce by budding or fission; Kurtzman, Fell, & Boekhout, 2011). These diverse yeasts inhabit floral nectar, extreme environments, soils, and insect bodies, among many other habitats (Buzzini, Turchetti, & Yurkov, 2018;Chappell & Fukami, 2018;Stefanini, 2018;Yurkov, 2018). One challenge of environmental yeast sampling is to minimize sampling biases so researchers can assure that observed diversity patterns are not artefacts of their chosen sampling strategy.…”