Uptake of Phytoplankton-Derived Carbon and Cobalamins by Novel Acidobacteria Genera in Microcystis Blooms Inferred from Metagenomic and Metatranscriptomic Evidence
Uptake of Phytoplankton-Derived Carbon and Cobalamins by Novel Acidobacteria Genera in Microcystis Blooms Inferred from Metagenomic and Metatranscriptomic Evidence
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DOI：
10.1128/aem.01803-21
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发表时间：
2022-07-05
影响因子：
4.4
通讯作者：
Dick，Gregory J.
中科院分区：
文献类型：
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作者：
Smith，Derek J.;Kharbush，Jenan J.;Dick，Gregory J.
细菌和浮游植物之间的相互作用可以影响初级生产力，群落组成和藻类水华的发展。然而，这些相互作用描述不佳的许多财团，特别是淡水水华形成蓝藻。在这里，我们评估的基因内容和表达的两个unculturedAcidobacteria从伊利湖微囊藻水华。这些生物是有针对性的，因为他们以前被确定为重要的过氧化氢酶生产商在微囊藻水华，这表明他们保护微囊藻从H2 O2。元转录组学显示，这两个Acidobacteriatransscribed基因摄取的有机化合物是已知的蓝藻产品和渗出物，包括乳酸盐，乙醇酸盐，氨基酸，肽，和钴。氨基酸代谢和肽运输和降解的表达基因表明，酸杆菌利用氨基酸和肽可以为蓝藻和其他生物体再生氮。酸性细菌基因组缺乏合成钴胺素的基因，但表达其运输和重塑的基因。这表明酸性细菌从外部获得钴胺素，可能来自微囊藻，微囊藻具有用于假钴胺素生物合成的完整基因库;在田间样品中表达它们;并在无菌培养中产生假钴胺素。在全球范围内的微囊藻水华中都检测到了这两种酸性细菌。总之，这些数据支持的假设，未培养和以前unidentifiedAcidobacteriataxa交换代谢产物与浮游植物在有害的蓝藻水华和影响氮可供浮游植物。因此，novelAcidobacteriamay在蓝藻生理和水华发展中发挥作用。重要异养细菌和浮游植物之间的相互作用影响浮游植物类群之间的竞争和演替，从而影响整个生态系统的过程，如碳循环和藻类水华的发展。蓝藻微囊藻在世界范围内的淡水中形成有害的水华，并在漂浮的群体中生长，在他们的藻球中庇护着其他细菌。藻圈和周围群落中的细菌可能影响微囊藻生理学和生态学，从而影响淡水有害蓝藻水华的发展。然而，细菌与微囊藻相互作用的影响和机制还不完全清楚。本研究采用群体基因组解析的方法，探讨微囊藻与藻囊藻中未培养藻体之间的相互作用机制，以研究全球范围内微囊藻与淡水酸性细菌水华的共存情况。
Interactions between bacteria and phytoplankton can influence primary production, community composition, and algal bloom development. However, these interactions are poorly described for many consortia, particularly for freshwater bloom-forming cyanobacteria. Here, we assessed the gene content and expression of two uncultivatedAcidobacteriafrom Lake ErieMicrocystisblooms. These organisms were targeted because they were previously identified as important catalase producers inMicrocystisblooms, suggesting that they protectMicrocystisfrom H2O2. Metatranscriptomics revealed that bothAcidobacteriatranscribed genes for uptake of organic compounds that are known cyanobacterial products and exudates, including lactate, glycolate, amino acids, peptides, and cobalamins. Expressed genes for amino acid metabolism and peptide transport and degradation suggest that use of amino acids and peptides byAcidobacteriamay regenerate nitrogen for cyanobacteria and other organisms. TheAcidobacteriagenomes lacked genes for biosynthesis of cobalamins but expressed genes for its transport and remodeling. This indicates that theAcidobacteriaobtained cobalamins externally, potentially fromMicrocystis, which has a complete gene repertoire for pseudocobalamin biosynthesis; expressed them in field samples; and produced pseudocobalamin in axenic culture. BothAcidobacteriawere detected inMicrocystisblooms worldwide. Together, the data support the hypotheses that uncultured and previously unidentifiedAcidobacteriataxa exchange metabolites with phytoplankton during harmful cyanobacterial blooms and influence nitrogen available to phytoplankton. Thus, novelAcidobacteriamay play a role in cyanobacterial physiology and bloom development.IMPORTANCEInteractions between heterotrophic bacteria and phytoplankton influence competition and successions between phytoplankton taxa, thereby influencing ecosystem-wide processes such as carbon cycling and algal bloom development. The cyanobacteriumMicrocystisforms harmful blooms in freshwaters worldwide and grows in buoyant colonies that harbor other bacteria in their phycospheres. Bacteria in the phycosphere and in the surrounding community likely influenceMicrocystisphysiology and ecology and thus the development of freshwater harmful cyanobacterial blooms. However, the impacts and mechanisms of interaction between bacteria andMicrocystisare not fully understood. This study explores the mechanisms of interaction betweenMicrocystisand uncultured members of its phycospherein situwith population genome resolution to investigate the cooccurrence ofMicrocystisand freshwaterAcidobacteriain blooms worldwide.