A cryptically diverse microbial community drives organic matter decomposition in forests

• Published in: Applied soil ecology : a section of Agriculture, ecosystems & environment Vol. 193; no. 1; p. 105148
• Main Authors: Maillard, François, Colin, Yannick, Viotti, Chloé, Buée, Marc, Brunner, Ivano, Brabcová, Vendula, Kohout, Petr, Baldrian, Petr, Kennedy, Peter G.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-01-2024; Elsevier
• Subjects: bacteria; Biologi; Biological Sciences; Cumulative OTU richness; Ecology; Ekologi; Environmental Sciences; Forest ecosystems; fungi; Life Sciences; Microbiology; Mikrobiologi; Natural Sciences; Naturvetenskap; Organic matter decomposition; Cumulative OTU richness; Forest ecosystems; bacteria; Organic matter decomposition; fungi
• ISSN: 0929-1393; 1873-0272
• DOI: 10.1016/j.apsoil.2023.105148

Despite the critical role of microorganisms in plant and fungal residue decomposition, our understanding of their full diversity remains limited. This is due largely to the rapid microbial succession during decomposition, a scarcity of studies including multiple sampling times, and the omission of a species richness index encompassing all decay stages. To address these gaps, we conducted a meta-analysis of 12 studies, each examining bacterial and fungal communities at multiple time points during decomposition. We aimed to determine the overall microbial diversity involved in decomposition processes by aggregating microbial richness at different time points. By comparing cumulative microbial OTU (operational taxonomic unit) richness with single time point microbial richness, we show that the cumulative richness was 2–5 times greater, indicating that a high yet frequently overlooked diversity of microorganisms is involved in the decomposition process. This pattern was consistent across different organic matter types (plant and fungal residues) for both major microbial domains (bacteria and fungi). Moreover, the appearance rate of novel OTUs generally decreased over time for most organic matter types, except for dead wood, which accumulated new fungal OTUs at a notable pace. Our results collectively emphasize the importance of considering various microbial domains, organic matter types, and time points to successfully characterize the diversity of microorganisms involved in decomposition. Further, given the hidden cumulative number of bacterial and fungal species held within plant and fungal residues across decay stages, we propose that these substrates are crucial microbial reservoirs to include to accurately assess global terrestrial microbial diversity.
•Cumulative microbial richness during residue decomposition was found to be 2-5 times greater than at single time points.•Leaf litter, root litter, and fungal residues displayed a decrease in the appearance rate of new microbial OTUs over time.•Dead wood showed a consistent increase in the appearance rate of new fungal OTUs over time.