Deep Aman, Sieber Guido, Boden Lisa, David Gwendoline M, Baikova Daria, Buchner Dominik, Starke Jörn, Stach Tom L, Reinders Torben, Hadžiomerović Una, Beszteri Sára, Probst Alexander J, Boenigk Jens, Beisser Daniela
Department of Engineering and Natural Sciences, Westphalian University of Applied Sciences, Recklinghausen, North Rhine-Westphalia, Germany.
Biodiversity, Faculty of Biology, University of Duisburg-Essen, Essen, North Rhine-Westphalia, Germany.
PeerJ. 2025 Apr 25;13:e19120. doi: 10.7717/peerj.19120. eCollection 2025.
The decomposition of organic matter is essential for sustaining the health of freshwater ecosystems by enabling nutrient recycling, sustaining food webs, and shaping habitat conditions, which collectively enhance ecosystem resilience and productivity. Bacteria and fungi play a crucial role in this process by breaking down coarse particulate organic matter (CPOM), such as leaf litter, into nutrients available for other organisms. However, the specific contribution of bacteria and their functional interactions with fungi in freshwater sediments have yet to be thoroughly explored. In the following study, we enriched organic matter through the addition of alder () leaves into artificial stream channels (AquaFlow mesocosms). We then investigated enzyme expression, metabolic pathways, and community composition of fungi and bacteria involved in the degradation of CPOM through metatranscriptomics and amplicon sequencing. Enzymes involved in the degradation of lignin, cellulose, and hemicellulose were selectively upregulated with increased organic matter. Analysis of ITS and 16S rRNA gene sequences revealed that during decomposition, fungal communities were predominantly composed of and , while bacterial communities were largely dominated by and . The similar gene expression patterns of CPOM degradation related enzymes observed between bacteria and fungi indicate potential functional interaction between these microbial groups. This correlation in enzyme expression may indicate that bacteria and fungi are jointly involved in the breakdown of coarse particulate organic matter, potentially through mutualistic interaction. This study uncovers the specific enzymatic activities of bacteria and fungi and the importance of microbial interactions in organic matter decomposition, revealing their central role in facilitating nutrient cycling and maintaining the ecological health and stability of freshwater ecosystems.
有机物的分解对于维持淡水生态系统的健康至关重要，它能够实现养分循环、维持食物网并塑造栖息地条件，这些共同增强了生态系统的恢复力和生产力。细菌和真菌在这一过程中发挥着关键作用，它们将粗颗粒有机物（CPOM），如落叶，分解为其他生物可利用的养分。然而，细菌在淡水沉积物中的具体贡献及其与真菌的功能相互作用尚未得到充分探索。在以下研究中，我们通过向人工溪流通道（AquaFlow中宇宙）添加桤木（）叶来富集有机物。然后，我们通过宏转录组学和扩增子测序研究了参与CPOM降解的真菌和细菌的酶表达、代谢途径和群落组成。随着有机物增加，参与木质素、纤维素和半纤维素降解的酶被选择性地上调。对ITS和16S rRNA基因序列的分析表明，在分解过程中，真菌群落主要由和组成，而细菌群落主要由和主导。在细菌和真菌之间观察到的CPOM降解相关酶的相似基因表达模式表明这些微生物群体之间存在潜在的功能相互作用。这种酶表达的相关性可能表明细菌和真菌共同参与粗颗粒有机物的分解，可能是通过互利共生相互作用。这项研究揭示了细菌和真菌的特定酶活性以及微生物相互作用在有机物分解中的重要性，揭示了它们在促进养分循环和维持淡水生态系统的生态健康与稳定性方面的核心作用。
