Microbiology of alpine cushion plants : biotic and abiotic drivers of alpine microbial communities assembly
Microorganisms are key component of Hearth biodiversity and ecosystem processes, especially in soils where they interact with plants. The objectives of the PhD was to caracterize the plant and abiotic respective influence on microbial spatial distribution. The work was based on a simplified soil bio...
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| Other Authors: | , , , |
| Format: | Doctoral or Postdoctoral Thesis |
| Language: | French |
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HAL CCSD
2014
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| Subjects: | |
| Online Access: | https://theses.hal.science/tel-01556470 https://theses.hal.science/tel-01556470/document https://theses.hal.science/tel-01556470/file/ROY_2014_archivage.pdf |
| Summary: | Microorganisms are key component of Hearth biodiversity and ecosystem processes, especially in soils where they interact with plants. The objectives of the PhD was to caracterize the plant and abiotic respective influence on microbial spatial distribution. The work was based on a simplified soil biology model, the alpine cushion plants. We choose one species composed of variable morphotype, Silene acaulis,can ecosystem engineer species that creates de novo soil through growth. Sampling design includes soil within cushions and outside, spanning altitudinal and geological gradients. Molecular approachs were used to describe diversity and to genotype cushions.Cushions structures bacterial and fungal regional beta diversity through a local buffering of the influence of abiotic context, homogeneizing soil pH and by nutrient supply. This engineering effect increased in stressful conditions and varied according to plant genotype. Betadiversity differed between bacteria and fungi. Bacterial communities are mainly influenced by pH and converge within cushions while fungal communities correlate to cushion genetic, especially plant-associated biotrophs fungal clades. This work shows that plants act as a major biotic filter on microbial biogeography. Les microorganismes occupent une place centrale dans la diversité du vivant et les processus écosystémiques, notamment dans le sol où ils sont en interaction avec les plantes. Cette thèse vise à caractériser l'influence respective des plantes et du contexte abiotique dans la distribution spatiale des microorganismes. Le travail s'appuie sur un modèle simplifié de la biologie des sols, les plantes en coussins des falaises de haute montagne. Nous avons suivi une seule espèce aux morphotypes variés, Silene acaulis, une espèce ingénieure de l'écosystème dont la croissance mène à la création d'un sol de novo. L'échantillonnage comprend le prélèvement de sol de plante et de sol extérieur comme témoin, pour des coussins distribués le long de gradients altitudinaux et géologiques. ... |
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