Impact of soil pedogenesis on the diversity and composition of fungal communities across the California soil chronosequence of Mendocino

P E Courty (1, 2, 3, 4) , Marc Buée (5) , J J T Tech (6) , D Brulé (1, 2, 3, 4) , Yannick Colin (5, 7) , J H J Leveau (6) , Stéphane Uroz (5, 7)

1 AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement
2 CNRS - Centre National de la Recherche Scientifique
3 INRA - Institut National de la Recherche Agronomique
4 UBFC - Université Bourgogne Franche-Comté [COMUE]
5 IAM - Interactions Arbres-Microorganismes
6 Dept Plant Pathol
7 BEF - Unité de recherche Biogéochimie des Ecosystèmes Forestiers

Understanding how soil pedogenesis affects microbial communities and their in situ activities according to ecosystem functioning is a central issue in soil microbial ecology, as soils represent essential nutrient reservoirs and habitats for the biosphere. To address this question, soil chronosequences developed from a single, shared mineralogical parent material and having the same climate conditions are particularly useful, as they isolate the factor of time from other factors controlling the character of soils. In our study, we considered a natural succession of uplifted marine terraces in Mendocino, CA, ranging from highly fertile in the younger terrace (about 100,000 years old) to infertile in the older terraces (about 300,000 years old). Using ITS amplicon pyrosequencing, we analysed and compared the diversity and composition of the soil fungal communities across the first terraces (T1 to T3), with a specific focus in the forested terraces (T2 and T3) on soil samples collected below trees of the same species (Pinus muricata) and of the same age. While diversity and richness indices were highest in the grassland (youngest) terrace (T1), they were higher in the older forested terrace (T3) compared to the younger forested terrace (T2). Interestingly, the most abundant ectomycorrhizal (ECM) taxa that we found within these fungal communities showed high homology with ITS Sanger sequences obtained previously directly from ECM root tips from trees in the same study site, revealing a relative conservation of ECM diversity over time. Altogether, our results provide new information about the diversity and composition of the fungal communities as well as on the dominant ECM species in the soil chronosequence of Mendocino in relation to soil age and ecosystem development.

Mots clés: Ectomycorrhizal fungi; Fungi; ITS-based pyrosequencing; Soil chronosequence; Soil horizons; Soil nutrients; pH; TERM ECOSYSTEM DEVELOPMENT; FINE-SCALE DISTRIBUTION; PYGMY FOREST REGION; ECTOMYCORRHIZAL FUNGI; BACTERIAL COMMUNITIES; NORTHERN CALIFORNIA; CENOCOCCUM-GEOPHILUM; BOREAL FORESTS; MIXED-CONIFER; EDAPHIC GRADIENT; pedogenesis; terrace; usa; microbial ecology

Mots clés: pédogénèse; communauté fongique; chronoséquence; terrasse; californie; états-unis; écologie microbienne

Domaines: Sciences du Vivant [q-bio]

P E Courty, Marc Buée, J J T Tech, D Brulé, Yannick Colin, et al.. Impact of soil pedogenesis on the diversity and composition of fungal communities across the California soil chronosequence of Mendocino. Mycorrhiza, 2018, 28 (4), pp.343-356. ⟨10.1007/s00572-018-0829-9⟩. ⟨hal-01815206⟩