Microbes on the Cliff: Alpine Cushion Plants Structure Bacterial and Fungal Communities

• Published in: Frontiers in Microbiology
• Main Authors: Roy, Julien, Albert, Cécile H., Ibanez, Sébastien, Saccone, P., Zinger, L., Choler, P., Clement, Jean-Christophe, Lavergne, S., Geremia, Roberto
• Other Authors: Laboratoire d'Ecologie Alpine (LECA), Université Joseph Fourier - Grenoble 1 (UJF)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS), Department of Biology Montréal, McGill University = Université McGill Montréal, Canada, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, University of Oulu, Station alpine Joseph Fourier - UMS 3370 (SAJF), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2013
• Subjects: alpine ecosystems; molecular fingerprint; foundation species; soil microbial communities; beta-diversity; elevation gradients; ecosystem engineering; Silene acaulis; envir; geo
• Online Access: https://doi.org/10.3389/fmicb.2013.00064; https://hal.archives-ouvertes.fr/hal-01688202/file/Roy%26al2013Front.Microb.pdf; https://hal.archives-ouvertes.fr/hal-01688202

International audience Plants affect the spatial distribution of soil microorganisms, but the influence of the local abiotic context is poorly documented. We investigated the effect of a single plant species, the cushion plant Silene acaulis, on habitat conditions, and microbial community. We collected soil from inside (In) and outside (Out) of the cushions on calcareous and siliceous cliffs in the French Alps along an elevation gradient (2,000–3,000 masl). The composition of the microbial communities was assessed by Capillary-Electrophoresis Single Strand Con-formation Polymorphism (CE-SSCP). Univariate and multivariate analyses were conducted to characterize the response of the microbial beta-diversity to soil parameters (total C, total N, soil water content, N − NH + 4 , N − NO − 3 , and pH). Cushions affected the microbial communities, modifying soil properties. The fungal and bacterial communities did not respond to the same abiotic factors. Outside the cushions, the bacterial communities were strongly influenced by bedrock. Inside the cushions, the bacterial communities from both types of bedrock were highly similar, due to the smaller pH differences than in open areas. By contrast, the fungal communities were equally variable inside and outside of the cushions. Outside the cushions, the fungal communities responded weakly to soil pH. Inside the cushions, the fungal communities varied strongly with bedrock and elevation as well as increases in soil nutrients and water content. Furthermore, the dissimilarities in the microbial communities between the In and Out habitats increased with increasing habitat modification and environmental stress. Our results indicate that cushions act as a selective force that counteracts the influence of the bedrock and the resource limitations on the bacterial and fungal communities by buffering soil pH and enhancing soil nutrients. Cushion plants structure microbial communities, and this effect increases in stressful, acidic and nutrient-limited environments.