PDF(Pubmed)
Abstract：
BACKGROUND: During the bloom season, the colonial cyanobacterium Microcystis forms complex aggregates which include a diverse microbiome within an exopolymer matrix. Early research postulated a simple mutualism existing with bacteria benefitting from the rich source of fixed carbon and Microcystis receiving recycled nutrients. Researchers have since hypothesized that Microcystis aggregates represent a community of synergistic and interacting species, an interactome, each with unique metabolic capabilities that are critical to the growth, maintenance, and demise of Microcystis blooms. Research has also shown that aggregate-associated bacteria are taxonomically different from free-living bacteria in the surrounding water. Moreover, research has identified little overlap in functional potential between Microcystis and members of its microbiome, further supporting the interactome concept. However, we still lack verification of general interaction and know little about the taxa and metabolic pathways supporting nutrient and metabolite cycling within Microcystis aggregates.
RESULTS: During a 7-month study of bacterial communities comparing free-living and aggregate-associated bacteria in Lake Taihu, China, we found that aerobic anoxygenic phototrophic (AAP) bacteria were significantly more abundant within Microcystis aggregates than in free-living samples, suggesting a possible functional role for AAP bacteria in overall aggregate community function. We then analyzed gene composition in 102 high-quality metagenome-assembled genomes (MAGs) of bloom-microbiome bacteria from 10 lakes spanning four continents, compared with 12 complete Microcystis genomes which revealed that microbiome bacteria and Microcystis possessed complementary biochemical pathways that could serve in C, N, S, and P cycling. Mapping published transcripts from Microcystis blooms onto a comprehensive AAP and non-AAP bacteria MAG database (226 MAGs) indicated that observed high levels of expression of genes involved in nutrient cycling pathways were in AAP bacteria.
CONCLUSIONS: Our results provide strong corroboration of the hypothesized Microcystis interactome and the first evidence that AAP bacteria may play an important role in nutrient cycling within Microcystis aggregate microbiomes. Video Abstract.
RESULTS: During a 7-month study of bacterial communities comparing free-living and aggregate-associated bacteria in Lake Taihu, China, we found that aerobic anoxygenic phototrophic (AAP) bacteria were significantly more abundant within Microcystis aggregates than in free-living samples, suggesting a possible functional role for AAP bacteria in overall aggregate community function. We then analyzed gene composition in 102 high-quality metagenome-assembled genomes (MAGs) of bloom-microbiome bacteria from 10 lakes spanning four continents, compared with 12 complete Microcystis genomes which revealed that microbiome bacteria and Microcystis possessed complementary biochemical pathways that could serve in C, N, S, and P cycling. Mapping published transcripts from Microcystis blooms onto a comprehensive AAP and non-AAP bacteria MAG database (226 MAGs) indicated that observed high levels of expression of genes involved in nutrient cycling pathways were in AAP bacteria.
CONCLUSIONS: Our results provide strong corroboration of the hypothesized Microcystis interactome and the first evidence that AAP bacteria may play an important role in nutrient cycling within Microcystis aggregate microbiomes. Video Abstract.
摘要：
背景：在开花季节，殖民地蓝细菌微囊藻形成复杂的聚集体，其中包括外聚合物基质内的多种微生物组。早期的研究假设存在一种简单的相互关系，细菌受益于丰富的固定碳和微囊藻接受回收营养的来源。此后，研究人员假设微囊藻聚集体代表了一个协同和相互作用的物种群落，一个相互作用的团体，每个人都有独特的代谢能力，对生长至关重要，维护,和微囊藻的消亡。研究还表明，与聚集相关的细菌在分类学上与周围水中的自由生活细菌不同。此外，研究发现，微囊藻和其微生物组成员之间的功能潜力几乎没有重叠，进一步支持相互作用组概念。然而,我们仍然缺乏对一般相互作用的验证,并且对支持微囊藻聚集体中营养物质和代谢物循环的分类单元和代谢途径知之甚少.
结果：在一项为期7个月的细菌群落研究中，比较了太湖的自由生活和聚集相关细菌，中国,我们发现，需氧缺氧光养（AAP）细菌在微囊藻聚集体中比在自由生活样品中明显更丰富，提示AAP细菌在总体聚集群落功能中可能发挥的功能作用。然后，我们分析了来自四大洲10个湖泊的102个高质量宏基因组组装基因组（MAG）中的基因组成，与12个完整的微囊藻基因组相比，这些基因组表明微生物组细菌和微囊藻具有互补的生化途径，N,S,和P循环。将微囊藻繁殖的已发表转录本映射到全面的AAP和非AAP细菌MAG数据库（226MAG）上，表明在AAP细菌中观察到与营养循环途径有关的基因的高水平表达。
结论：我们的结果为假设的微囊藻相互作用组提供了有力的佐证，并首次证明AAP细菌可能在微囊藻聚集微生物群中的营养循环中起重要作用。视频摘要。
结果：在一项为期7个月的细菌群落研究中，比较了太湖的自由生活和聚集相关细菌，中国,我们发现，需氧缺氧光养（AAP）细菌在微囊藻聚集体中比在自由生活样品中明显更丰富，提示AAP细菌在总体聚集群落功能中可能发挥的功能作用。然后，我们分析了来自四大洲10个湖泊的102个高质量宏基因组组装基因组（MAG）中的基因组成，与12个完整的微囊藻基因组相比，这些基因组表明微生物组细菌和微囊藻具有互补的生化途径，N,S,和P循环。将微囊藻繁殖的已发表转录本映射到全面的AAP和非AAP细菌MAG数据库（226MAG）上，表明在AAP细菌中观察到与营养循环途径有关的基因的高水平表达。
结论：我们的结果为假设的微囊藻相互作用组提供了有力的佐证，并首次证明AAP细菌可能在微囊藻聚集微生物群中的营养循环中起重要作用。视频摘要。
