The mysterious world of yeasts in the lengas of the Andes mountain range

It should be noted that this Research Center is carrying out the genetic characterization of the samples obtained. A full year’s worth of information will soon be available.

Lorenzo Palma, Science in Chile.- From the center to the extreme south of the country, a group of researchers is taking samples of the yeasts present in the lenga forests, from the bark and roots, in the area of ​​the treeline or limit of tree life to identify how the forest determines the spatio-temporal distribution of these microorganisms.

In Chillán, Villarrica, Antillanca and Coyhaique, a group of yeast specialists have set themselves the challenge of collecting bark samples from lenga forests to detect the presence of native yeasts, such is the case of Saccharomyces eubayanus. Of which, its ecology in winter seasons and its ability to resist low temperatures and freezing processes are still unknown.

The treeline is considered a true natural experiment worldwide. Because, this limiting line of forest growth occurs at a mean ground temperature equivalent to 6.4 ± 0.7 °C, regardless of latitude and tree species, indicating that it is a temperature-controlled vegetation ecotone.

What are yeasts? Christian Oporto, a member of the LiLi Nucleus, explains that they are unicellular fungi, which are closely related to human activities, due to their use in various fermented foods and beverages. 8 species of yeasts have been described Saccharomyces to date, that have been isolated from food, human skin, insects, or trees, but the only confirmed common environment is temperate forests.

Temperate forests are distributed throughout much of the world. “It has been described that yeasts have completely colonized these environments, where it has been possible to isolate yeasts from samples of soil, bark, fruits, flowers, leaves and branches”, details the researcher and current doctoral candidate of the LiLi Millennium Nucleus, commenting that, “S. eubayanus apparently its natural niche is the lenga trees, which are part of these temperate forests.”

It should be noted that the LiLi Millennium Nucleus or “Patagonian life limit: environmental restrictions in genetics and ecophysiology”, is directed by the doctor in Biological Sciences, Roberto Nespolo, from the Austral University of Chile and is financed by the National Research Agency of Chile (ANID).

The LiLi Nucleus researchers indicate that it was previously known that S. eubayanus is present in the four study areas mentioned, with that its objective is to identify if there are genetic and phenotypic differences between the yeast isolates present in each study area that are distributed latitudinally and in which different climatic conditions are presented, as well as well as altitude variations, and in this way, determine how these variables are responsible for the genetic and phenotypic variations in the species.

The Lenga

A particular tree that is studying the LiLi Millennium Core is the lenga (Nothofagus pumilio), whose height reaches 35 meters high, but, in the area of ​​the treeline or limit of life, its size is very reduced, it does not even exceed 5 meters.

Oporto adds that the lenga is characterized by being present at relatively high elevations, where climatic conditions are very intense, where large amounts of snow stand out in winter and low temperatures throughout the year. “In this way, as much as the lenga and S. eubayanus, have been able to adapt to these conditions and have been directly related. In this way, this project seeks to understand even better the association of S. eubayanus with the Lenga”, he commented.

In both Chile and Argentina, pure lenga forests are found in the tree line area. Its presence varies from north to south. A peculiarity of this species in the treeline is that it is deciduous, this means that each year it loses its leaves. Something unusual compared to other trees that mark the tree line in other countries.

The greatest challenge of this work corresponds to sampling lenga bark at the limit of life. This is due to the fact that the tree line is at a high altitude, added also to the extreme weather conditions, mainly in winter, where we can find large amounts of snow, heavy rains and winds and also, without neglecting the low temperatures .

The lenga is on the highest floor of the Andean ecosystems and forms forest masses that are called pure. It grows more than 25 meters tall and diameters of 1.5 meters have been recorded. These measurements are restricted to treeline trees. His problem is growing tall.

The main researcher of the LiLi Nucleus, Francisco Cubillos, an academic from the University of Santiago de Chile (USACH), detailed the importance for the knowledge of the genetic variability of the country’s yeasts “Yeasts are unicellular fungi that benefit from the resources provided in the forest. Our primary forest is extensive and hosts a unique genetic diversity in the world. Therefore, studying this biological resource will allow us to understand how the forest of Nothofagus promotes the life of microorganisms according to latitude and altitude, and how this varies according to the season of the year. We are facing a natural laboratory, which we must protect and discuss through genetic and ecological studies that will give us the answers to determine how these species will respond to climate change” he concluded.