Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Avenida Antônio Carlos 6627, Belo Horizonte, MG, 31270-901, Brazil.
Department of Aquatic Ecology and Environmental Biology, Institute for Water and Wetland Research, Radboud University, Nijmegen, The Netherlands.
Microb Ecol. 2019 Oct;78(3):575-588. doi: 10.1007/s00248-019-01331-9. Epub 2019 Feb 1.
Water hyacinth (WH), a large floating plant, plays an important role in the biogeochemistry and ecology of many freshwaters globally. Its biogeochemical impact on wetland functioning is strongly mediated by the microbiome associated with its roots. However, little is known about the structure and function of this WH rhizobiome and its relation to wetland ecosystem functioning. Here, we unveil the core and transient rhizobiomes of WH and their key biogeochemical functions in two of the world's largest wetlands: the Amazon and the Pantanal. WH hosts a highly diverse microbial community shaped by spatiotemporal changes. Proteobacteria lineages were most common, followed by Actinobacteria and Planctomycetes. Deltaproteobacteria and Sphingobacteriia predominated in the core microbiome, potentially associated with polysaccharide degradation and fermentation of plant-derived carbon. Conversely, a plethora of lineages were transient, including highly abundant Acinetobacter, Acidobacteria subgroup 6, and methanotrophs, thus assuring diverse taxonomic signatures in the two different wetlands. Our findings point out that methanogenesis is a key driver of, and proxy for, community structure, especially during seasonal plant decline. We provide ecologically relevant insights into the WH microbiome, which is a key element linking plant-associated carbon turnover with other biogeochemical fluxes in tropical wetlands.
水葫芦（WH）是一种大型漂浮植物，在全球许多淡水的生物地球化学和生态学中发挥着重要作用。其与根系相关的微生物组强烈调节了其对湿地功能的生物地球化学影响。然而，人们对这种 WH 根瘤菌的结构和功能及其与湿地生态系统功能的关系知之甚少。在这里，我们揭示了世界上两个最大的湿地——亚马逊和潘塔纳尔湿地中 WH 的核心和瞬变根瘤菌及其关键生物地球化学功能。WH 拥有一个由时空变化塑造的高度多样化的微生物群落。变形菌门的类群最为常见，其次是放线菌门和浮霉菌门。δ变形菌门和鞘脂单胞菌门在核心微生物组中占优势，可能与多糖降解和植物衍生碳的发酵有关。相反，大量的类群是瞬变的，包括丰度很高的不动杆菌、酸杆菌亚群 6 和产甲烷菌，从而确保了两个不同湿地中多样化的分类特征。我们的研究结果表明，甲烷生成是群落结构的关键驱动因素和代理，特别是在季节性植物衰退期间。我们为 WH 微生物组提供了具有生态相关性的见解，这是将植物相关碳周转与热带湿地中其他生物地球化学通量联系起来的关键因素。
