CONICET | Buscador de Institutos y Recursos Humanos

Nothofagus nervosa is an ecologically and economically important species of South American temperate forests. In Argentina, it has a reduced natural distribution area due to overexploitation, overgrazing and forest fires. This critical situation led to the implementation of conservation and domestication programs. Among the different factors that should be considered in these programs and subsequently in reforestation activities are the mycorrhizas and yeasts associated with this species. These microorganisms function as growth promoting and phytodefense agents, so they are of great importance for seedlings growth and for their implantation in the field. The general aim of this work is to analyze the abundance and diversity of mycorrhizas and yeasts in N. nervosa, to compare them between native and nursery cultivated individuals and finally to select some mycorrhizas and yeasts strains which would have significant biotechnological applications in domestication processes and therefore in forest management. The first step was to analyze the yeasts associated with N. nervosa seeds, they influence the microbial succession that occurs when seeds germinate and consequently they have an effect on plant fitness and development, hence it is crucial to study and describe them. Yeasts were isolated from 30 seeds. Each seed was put into an eppendorf containing 1mL of sterile 0.9% NaCl and sand, and was vortex-mixed for 2 minutes. Aliquots of 100ul were spread on MYP agar plates supplemented with 0.01% chloramphenicol. Plates were incubated at 20°C for 72hs. One-hundred-forty-nine strains were isolated. Hitherto, they have not been completely identified, because their morphological and biochemical characterizations are still being carried out and molecular identification has to be done. According to these preliminary results, N. nervosa seeds have a diverse community of yeasts, including some strains that develop pseudomicelia and some black-yeasts. This work contributes to the description of yeasts biodiversity in natural environments of Patagonia and constitutes the initial step in the study of the influence of these microorganisms in plant growth. It also provides a base for further investigations, such as yeasts-mycorrhizas interactions and possible biotechnological applications of both types of microorganisms in the improvement of plant fitness and the enhancement of domestication programs.