Campbell Tayte P, Ulrich Danielle E M, Toyoda Jason, Thompson Jaron, Munsky Brian, Albright Michaeline B N, Bailey Vanessa L, Tfaily Malak M, Dunbar John
Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, United States.
Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM, United States.
Front Microbiol. 2022 Jan 20;12:799014. doi: 10.3389/fmicb.2021.799014. eCollection 2021.
Rapid microbial growth in the early phase of plant litter decomposition is viewed as an important component of soil organic matter (SOM) formation. However, the microbial taxa and chemical substrates that correlate with carbon storage are not well resolved. The complexity of microbial communities and diverse substrate chemistries that occur in natural soils make it difficult to identify links between community membership and decomposition processes in the soil environment. To identify potential relationships between microbes, soil organic matter, and their impact on carbon storage, we used sand microcosms to control for external environmental factors such as changes in temperature and moisture as well as the variability in available carbon that exist in soil cores. Using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) on microcosm samples from early phase litter decomposition, we found that protein- and tannin-like compounds exhibited the strongest correlation to dissolved organic carbon (DOC) concentration. Proteins correlated positively with DOC concentration, while tannins correlated negatively with DOC. Through random forest, neural network, and indicator species analyses, we identified 42 bacterial and 9 fungal taxa associated with DOC concentration. The majority of bacterial taxa (26 out of 42 taxa) belonged to the phylum Proteobacteria while all fungal taxa belonged to the phylum Ascomycota. Additionally, we identified significant connections between microorganisms and protein-like compounds and found that most taxa (12/14) correlated negatively with proteins indicating that microbial consumption of proteins is likely a significant driver of DOC concentration. This research links DOC concentration with microbial production and/or decomposition of specific metabolites to improve our understanding of microbial metabolism and carbon persistence.
植物凋落物分解早期微生物的快速生长被视为土壤有机质（SOM）形成的重要组成部分。然而，与碳储存相关的微生物分类群和化学底物尚未得到很好的解析。自然土壤中微生物群落的复杂性和多样的底物化学性质使得难以确定土壤环境中群落组成与分解过程之间的联系。为了确定微生物、土壤有机质及其对碳储存的影响之间的潜在关系，我们使用砂质微宇宙来控制外部环境因素，如温度和湿度的变化以及土壤核心中存在的有效碳的变异性。通过对凋落物分解早期微宇宙样品进行傅里叶变换离子回旋共振质谱（FTICR-MS）分析，我们发现蛋白质类和单宁类化合物与溶解有机碳（DOC）浓度的相关性最强。蛋白质与DOC浓度呈正相关，而单宁与DOC呈负相关。通过随机森林、神经网络和指示物种分析，我们确定了42种细菌和9种真菌分类群与DOC浓度相关。大多数细菌分类群（42个分类群中的26个）属于变形菌门，而所有真菌分类群都属于子囊菌门。此外，我们确定了微生物与蛋白质类化合物之间的重要联系，并发现大多数分类群（12/14）与蛋白质呈负相关，这表明微生物对蛋白质的消耗可能是DOC浓度的一个重要驱动因素。这项研究将DOC浓度与特定代谢物的微生物产生和/或分解联系起来，以增进我们对微生物代谢和碳持久性的理解。
