Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany.
Humboldt-Universität zu Berlin, Institute of Biology, Ecology Group, Berlin, Germany.
Environ Microbiol. 2024 Nov;26(11):e70007. doi: 10.1111/1462-2920.70007.
Bacterivorous nematodes are important grazers in the soil micro-food web. Their trophic regulation shapes the composition and ecosystem services of the soil microbiome, but the underlying population dynamics of bacteria and archaea are poorly understood. We followed soil respiration and 221 dominant bacterial and archaeal 16S rRNA gene amplicon sequencing variants (ASVs) in response to top-down control by a common bacterivorous soil nematode, Acrobeloides buetschlii, bottom-up control by maize litter amendment and their combination over 32 days. Maize litter amendment significantly increased soil respiration, while A. buetschlii addition caused an earlier peak in soil respiration. Underlying bacterial and archaeal population dynamics separated into five major response types, differentiating in their temporal abundance maxima and minima. In-depth analysis of these population dynamics identified a broad imprint of A. buetschlii grazing on dominant bacterial (Acidobacteriota, Bacteroidota, Gemmatimonadota, Pseudomonadota) and archaeal (Nitrososphaerota) ASVs. Combined bottom-up control by maize litter and top-down control by A. buetschlii grazing caused a succession of soil microbiota, driven by population changes first in the Bacteroidota, then in the Pseudomonadota and finally in the Acidobacteriota and Nitrososphaerota. Our results are an essential step forward in understanding trophic modulation of soil microbiota and its feedback on soil respiration.
食细菌线虫是土壤微食物网中的重要捕食者。它们的营养调节塑造了土壤微生物组的组成和生态系统服务，但细菌和古菌的潜在种群动态仍了解甚少。我们跟踪了土壤呼吸和 221 个主要细菌和古菌 16S rRNA 基因扩增子测序变体 (ASV)，以响应常见食细菌土壤线虫 Acrobeloides buetschlii 的自上而下的控制、玉米凋落物添加的自下而上的控制及其在 32 天内的组合。玉米凋落物添加显著增加了土壤呼吸，而 A. buetschlii 的添加导致土壤呼吸更早地达到峰值。潜在的细菌和古菌种群动态分为五种主要的响应类型，在它们的时间丰度最大值和最小值上有所区别。对这些种群动态的深入分析确定了 A. buetschlii 捕食对主要细菌（酸杆菌门、拟杆菌门、芽单胞菌门、假单胞菌门）和古菌（硝化螺旋菌门）ASV 的广泛影响。玉米凋落物的自下而上的控制和 A. buetschlii 的自上而下的控制相结合，导致了土壤微生物群的连续演替，首先是在拟杆菌门，然后是在假单胞菌门，最后是在酸杆菌门和硝化螺旋菌门。我们的研究结果是深入了解土壤微生物群的营养调节及其对土壤呼吸的反馈的重要一步。
