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Cai H, McLimans CJ, Jiang H, Chen F, Krumholz LR, Hambright KD. Aerobic anoxygenic phototrophs play important roles in nutrient cycling within cyanobacterial Microcystis bloom microbiomes. MICROBIOME 2024; 12:88. [PMID: 38741135 PMCID: PMC11089705 DOI: 10.1186/s40168-024-01801-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 03/25/2024] [Indexed: 05/16/2024]
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.
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Affiliation(s)
- Haiyuan Cai
- School of Biological Sciences, University of Oklahoma, Norman, USA
- Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China
| | | | - Helong Jiang
- Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China
| | - Feng Chen
- Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science, Baltimore, USA
| | - Lee R Krumholz
- School of Biological Sciences, University of Oklahoma, Norman, USA
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Piccini C, Martínez de la Escalera G, Segura AM, Croci C, Kruk C. The Microcystis-microbiome interactions: origins of the colonial lifestyle. FEMS Microbiol Ecol 2024; 100:fiae035. [PMID: 38499447 PMCID: PMC10996927 DOI: 10.1093/femsec/fiae035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 02/21/2024] [Accepted: 03/16/2024] [Indexed: 03/20/2024] Open
Abstract
Species of the Microcystis genus are the most common bloom-forming toxic cyanobacteria worldwide. They belong to a clade of unicellular cyanobacteria whose ability to reach high biomasses during blooms is linked to the formation of colonies. Colonial lifestyle provides several advantages under stressing conditions of light intensity, ultraviolet light, toxic substances and grazing. The progression from a single-celled organism to multicellularity in Microcystis has usually been interpreted as individual phenotypic responses of the cyanobacterial cells to the environment. Here, we synthesize current knowledge about Microcystis colonial lifestyle and its role in the organism ecology. We then briefly review the available information on Microcystis microbiome and propose that changes leading from single cells to colonies are the consequence of specific and tightly regulated signals between the cyanobacterium and its microbiome through a biofilm-like mechanism. The resulting colony is a multi-specific community of interdependent microorganisms.
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Affiliation(s)
- Claudia Piccini
- Departamento de Microbiología, Centro de Investigación en Ciencias Ambientales, Instituto de Investigaciones Biológicas Clemente Estable. Av. Italia 3318, Montevideo 11600, Uruguay
| | - Gabriela Martínez de la Escalera
- Departamento de Microbiología, Centro de Investigación en Ciencias Ambientales, Instituto de Investigaciones Biológicas Clemente Estable. Av. Italia 3318, Montevideo 11600, Uruguay
| | - Angel M Segura
- Modelización Estadística de Datos e Inteligencia Artificial, Centro Universitario Regional del Este, Universidad de la República. Ruta nacional Nº9 intersección con ruta Nº15, Uruguay
| | - Carolina Croci
- Departamento de Microbiología, Centro de Investigación en Ciencias Ambientales, Instituto de Investigaciones Biológicas Clemente Estable. Av. Italia 3318, Montevideo 11600, Uruguay
| | - Carla Kruk
- Modelización Estadística de Datos e Inteligencia Artificial, Centro Universitario Regional del Este, Universidad de la República. Ruta nacional Nº9 intersección con ruta Nº15, Uruguay
- Sección Limnología, Instituto de Ecología y Ciencias Ambientales, Facultad de Ciencias, Universidad de la República. Iguá 4225, Montevideo 11400, Uruguay
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Woodhouse JN, Burford MA, Neilan BA, Jex A, Tichkule S, Sivonen K, Fewer DP, Grossart HP, Willis A. Long-term stability of the genome structure of the cyanobacterium, Dolichospermum in a deep German lake. HARMFUL ALGAE 2024; 133:102600. [PMID: 38485438 DOI: 10.1016/j.hal.2024.102600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 01/31/2024] [Accepted: 02/05/2024] [Indexed: 03/19/2024]
Abstract
Dolichospermum is a cyanobacterial genus commonly associated with toxic blooms in lakes and brackish water bodies worldwide, and is a long-term resident of Lake Stechlin, northeastern Germany. In recent decades, shifts in the phosphorus loading and phytoplankton species composition have seen increased biomass of Dolichospermum during summer blooms from 1998, peaking around 2005, and declining after 2020. Cyanobacteria are known to rapidly adapt to new environments, facilitated by genome adaptation. To investigate the changes in genomic features that may have occurred in Lake Stechlin Dolichospermum during this time of increased phosphorus loading and higher biomass, whole genome sequence analysis was performed on samples of ten akinetes isolated from ten, 1 cm segments of a sediment core, representing a ∼45-year period from 1970 to 2017. Comparison of these genomes with genomes of extant isolates revealed a clade of Dolichospermum that clustered with the ADA-6 genus complex, with remarkable genome stability, without gene gain or loss events in response to recent environmental changes. The genome characteristics indicate that this species is suited to a deep-chlorophyll maximum, including additional light-harvesting and phosphorus scavenging genes. Population SNP analysis revealed two sub-populations that shifted in dominance as the lake transitioned between oligotrophic and eutrophic conditions. Overall, the results show little change within the population, despite diversity between extant populations from different geographic locations and the in-lake changes in phosphorus concentrations.
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Affiliation(s)
- J N Woodhouse
- Department of Plankton and Microbial Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), 16775 Stechlin, Germany
| | - M A Burford
- Australian Rivers Institute, and School of Environment and Science, Griffith University, Brisbane, Australia
| | - B A Neilan
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan 2308, NSW, Australia
| | - A Jex
- Population Health and Immunity, Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia; Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, VIC, Australia
| | - S Tichkule
- Population Health and Immunity, Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia; Department of Medical Biology, University of Melbourne, Melbourne, Australia
| | - K Sivonen
- Department of Microbiology, University of Helsinki, Viikinkaari 9, FI-00014 Helsinki, Finland
| | - D P Fewer
- Department of Microbiology, University of Helsinki, Viikinkaari 9, FI-00014 Helsinki, Finland
| | - H-P Grossart
- Department of Plankton and Microbial Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), 16775 Stechlin, Germany; Department of Biochemistry and Biology, Potsdam University, 14469 Potsdam, Germany
| | - A Willis
- Australian Rivers Institute, and School of Environment and Science, Griffith University, Brisbane, Australia.
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Baker D, Godwin CM, Khanam M, Burtner AM, Dick GJ, Denef VJ. Variation in resource competition traits among Microcystis strains is affected by their microbiomes. MLIFE 2023; 2:401-415. [PMID: 38818269 PMCID: PMC10989160 DOI: 10.1002/mlf2.12094] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 10/11/2023] [Accepted: 10/13/2023] [Indexed: 06/01/2024]
Abstract
Freshwater harmful algal blooms are often dominated by Microcystis, a phylogenetically cohesive group of cyanobacteria marked by extensive genetic and physiological diversity. We have previously shown that this genetic diversity and the presence of a microbiome of heterotrophic bacteria influences competitive interactions with eukaryotic phytoplankton. In this study, we sought to explain these observations by characterizing Monod equation parameters for resource usage (maximum growth rate μ max, half-saturation value for growth K s, and quota) as a function of N and P levels for four strains (NIES-843, PCC 9701, PCC 7806 [WT], and PCC 7806 ΔmcyB) in presence and absence of a microbiome derived from Microcystis isolated from Lake Erie. Results indicated limited differences in maximum growth rates but more pronounced differences in half-saturation values among Microcystis strains. The largest impact of the microbiome was reducing the minimal nitrogen concentration sustaining growth and reducing half saturation values, with variable results depending on the Microcystis strain. Microcystis strains also differed from each other in their N and P quotas and the extent to which microbiome presence affected them. Our data highlight the importance of the microbiome in altering Microcystis-intrinsic traits, strain competitive hierarchies, and thus bloom dynamics. As quota, μ max, and K s are commonly used in models for harmful algal blooms, our data suggest that model improvement may be possible by incorporating genotype dependencies of resource-use parameters.
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Affiliation(s)
- Dylan Baker
- Department of Ecology and Evolutionary BiologyUniversity of MichiganAnn ArborMichiganUSA
| | - Casey M. Godwin
- Cooperative Institute for Great Lakes Research, School for Environment and SustainabilityUniversity of MichiganAnn ArborMichiganUSA
| | - Muhtamim Khanam
- Department of Ecology and Evolutionary BiologyUniversity of MichiganAnn ArborMichiganUSA
| | - Ashley M. Burtner
- Cooperative Institute for Great Lakes Research, School for Environment and SustainabilityUniversity of MichiganAnn ArborMichiganUSA
| | - Gregory J. Dick
- Cooperative Institute for Great Lakes Research, School for Environment and SustainabilityUniversity of MichiganAnn ArborMichiganUSA
- Department of Earth and Environmental SciencesUniversity of MichiganAnn ArborMichiganUSA
| | - Vincent J. Denef
- Department of Ecology and Evolutionary BiologyUniversity of MichiganAnn ArborMichiganUSA
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Jackrel SL, White JD, Perez-Coronel E, Koch RY. Selection for oligotrophy among bacteria inhabiting host microbiomes. mBio 2023; 14:e0141523. [PMID: 37646528 PMCID: PMC10653850 DOI: 10.1128/mbio.01415-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 07/04/2023] [Indexed: 09/01/2023] Open
Abstract
IMPORTANCE Understanding how natural selection has historically shaped the traits of microbial populations comprising host microbiomes would help predict how the functions of these microbes may continue to evolve over space and time. Numerous host-associated microbes have been found to adapt to their host, sometimes becoming obligate symbionts, whereas free-living microbes are best known to adapt to their surrounding environment. Our study assessed the selective pressures of both the host environment and the surrounding external environment in shaping the functional potential of host-associated bacteria. Despite residing within the resource-rich microbiome of their hosts, we demonstrate that host-associated heterotrophic bacteria show evidence of trait selection that matches the nutrient availability of their broader surrounding environment. These findings illustrate the complex mix of selective pressures that likely shape the present-day function of bacteria found inhabiting host microbiomes. Our study lends insight into the shifts in function that may occur as environments fluctuate over time.
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Affiliation(s)
- Sara L. Jackrel
- Department of Ecology, Behavior and Evolution, University of California San Diego, La Jolla, California, USA
| | - Jeffrey D. White
- Department of Biology, Framingham State University, Framingham, Massachusetts, USA
| | - Elisabet Perez-Coronel
- Department of Ecology, Behavior and Evolution, University of California San Diego, La Jolla, California, USA
| | - Ryan Y. Koch
- Department of Ecology, Behavior and Evolution, University of California San Diego, La Jolla, California, USA
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Zhang X, Xiao L, Liu J, Tian Q, Xie J. Trade-off in genome turnover events leading to adaptive evolution of Microcystis aeruginosa species complex. BMC Genomics 2023; 24:462. [PMID: 37592233 PMCID: PMC10433662 DOI: 10.1186/s12864-023-09555-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 08/04/2023] [Indexed: 08/19/2023] Open
Abstract
BACKGROUND Numerous studies in the past have expanded our understanding of the genetic differences of global distributed cyanobacteria that originated around billions of years ago, however, unraveling how gene gain and loss drive the genetic evolution of cyanobacterial species, and the trade-off of these evolutionary forces are still the central but poorly understood issues. RESULTS To delineate the contribution of gene flow in mediating the hereditary differentiation and shaping the microbial evolution, a global genome-wide study of bloom-forming cyanobacterium, Microcystis aeruginosa species complex, provided robust evidence for genetic diversity, reflected by enormous variation in gene repertoire among various strains. Mathematical extrapolation showed an 'open' microbial pan-genome of M. aeruginosa species, since novel genes were predicted to be introduced after new genomes were sequenced. Identification of numerous horizontal gene transfer's signatures in genome regions of interest suggested that genome expansion via transformation and phage-mediated transduction across bacterial lineage as an evolutionary route may contribute to the differentiation of Microcystis functions (e.g., carbohydrate metabolism, amino acid metabolism, and energy metabolism). Meanwhile, the selective loss of some dispensable genes at the cost of metabolic versatility is as a mean of adaptive evolution that has the potential to increase the biological fitness. CONCLUSIONS Now that the recruitment of novel genes was accompanied by a parallel loss of some other ones, a trade-off in gene content may drive the divergent differentiation of M. aeruginosa genomes. Our study provides a genetic framework for the evolution of M. aeruginosa species and illustrates their possible evolutionary patterns.
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Affiliation(s)
- Xian Zhang
- Department of Occupational and Environmental Health, Xiangya School of Public Health, Central South University, Changsha, China.
- Hunan Provincial Key Laboratory of Clinical Epidemiology, Central South University, Changsha, China.
| | - Lijun Xiao
- Guangdong Corps Hospital of Chinese People's Armed Police Forces, Guangzhou, China
| | - Jiahui Liu
- Department of Occupational and Environmental Health, Xiangya School of Public Health, Central South University, Changsha, China
| | - Qibai Tian
- Department of Occupational and Environmental Health, Xiangya School of Public Health, Central South University, Changsha, China
| | - Jiaqi Xie
- Hunan Food and Drug Vocational College, Changsha, China
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7
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Yancey CE, Kiledal EA, Chaganti SR, Denef VJ, Errera RM, Evans JT, Hart LN, Isailovic D, James WS, Kharbush JJ, Kimbrel JA, Li W, Mayali X, Nitschky H, Polik CA, Powers MA, Premathilaka SH, Rappuhn NA, Reitz LA, Rivera SR, Zwiers CC, Dick GJ. The Western Lake Erie culture collection: A promising resource for evaluating the physiological and genetic diversity of Microcystis and its associated microbiome. HARMFUL ALGAE 2023; 126:102440. [PMID: 37290887 DOI: 10.1016/j.hal.2023.102440] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 04/24/2023] [Accepted: 04/28/2023] [Indexed: 06/10/2023]
Abstract
Cyanobacterial harmful algal blooms (cyanoHABs) dominated by Microcystis spp. have significant public health and economic implications in freshwater bodies around the world. These blooms are capable of producing a variety of cyanotoxins, including microcystins, that affect fishing and tourism industries, human and environmental health, and access to drinking water. In this study, we isolated and sequenced the genomes of 21 primarily unialgal Microcystis cultures collected from western Lake Erie between 2017 and 2019. While some cultures isolated in different years have a high degree of genetic similarity (genomic Average Nucleotide Identity >99%), genomic data show that these cultures also represent much of the breadth of known Microcystis diversity in natural populations. Only five isolates contained all the genes required for microcystin biosynthesis while two isolates contained a previously described partial mcy operon. Microcystin production within cultures was also assessed using Enzyme-Linked Immunosorbent Assay (ELISA) and supported genomic results with high concentrations (up to 900 μg L⁻¹) in cultures with complete mcy operons and no or low toxin detected otherwise. These xenic cultures also contained a substantial diversity of bacteria associated with Microcystis, which has become increasingly recognized as an essential component of cyanoHAB community dynamics. These results highlight the genomic diversity among Microcystis strains and associated bacteria in Lake Erie, and their potential impacts on bloom development, toxin production, and toxin degradation. This culture collection significantly increases the availability of environmentally relevant Microcystis strains from temperate North America.
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Affiliation(s)
- Colleen E Yancey
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - E Anders Kiledal
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Subba Rao Chaganti
- Cooperative Institute for Great Lakes Research (CIGLR), University of Michigan, 4840 S State Road, Ann Arbor, MI 48108, United States of America
| | - Vincent J Denef
- Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Reagan M Errera
- National Oceanic and Atmospheric Administration (NOAA), Great Lakes Environmental Research Laboratory (GLERL), 4840 S State Road, Ann Arbor, MI 48108, United States of America
| | - Jacob T Evans
- Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Lauren N Hart
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109, United States of America; Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Dragan Isailovic
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH 43606, United States of America
| | - William S James
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Jenan J Kharbush
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Jeffrey A Kimbrel
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, United States of America
| | - Wei Li
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, United States of America
| | - Xavier Mayali
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, United States of America
| | - Helena Nitschky
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Catherine A Polik
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - McKenzie A Powers
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Sanduni H Premathilaka
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH 43606, United States of America
| | - Nicole A Rappuhn
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Laura A Reitz
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Sara R Rivera
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Claire C Zwiers
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Gregory J Dick
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States of America; Cooperative Institute for Great Lakes Research (CIGLR), University of Michigan, 4840 S State Road, Ann Arbor, MI 48108, United States of America.
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Halary S, Duperron S, Kim Tiam S, Duval C, Bernard C, Marie B. Intra-population genomic diversity of the bloom-forming cyanobacterium, Aphanizomenon gracile, at low spatial scale. ISME COMMUNICATIONS 2023; 3:57. [PMID: 37280295 PMCID: PMC10244403 DOI: 10.1038/s43705-023-00263-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 05/09/2023] [Accepted: 05/24/2023] [Indexed: 06/08/2023]
Abstract
Cyanobacteria are oxygenic photosynthetic bacteria that perform a substantial part of the global primary production. Some species are responsible for catastrophic environmental events, called blooms, which have become increasingly common in lakes and freshwater bodies as a consequence of global changes. Genotypic diversity is considered essential for marine cyanobacterial population, allowing it to cope with spatio-temporal environmental variations and to adapt to specific micro-niches in the ecosystem. This aspect is underestimated in the study of bloom development, however, and given little notice in studies of the ecology of harmful cyanobacteria. Here we compared the genomes of four strains of Aphanizomenon gracile, a species of filamentous toxinogenic cyanobacteria (Nostocales) found worldwide in fresh and brackish water. Millimeter-sized fascicles were isolated from a single water sample and have been maintained in culture since 2010. A comparative study revealed extensive heterogeneity in gene contents, despite similar genome size and high similarity indices. These variations were mainly associated with mobile genetic elements and biosynthetic gene clusters. For some of the latter, metabolomic analysis confirmed the production of related secondary metabolites, such as cyanotoxins and carotenoids, which are thought to play a fundamental role in the cyanobacterial fitness. Altogether, these results demonstrated that an A. gracile bloom could be a highly diverse population at low spatial scale and raised questions about potential exchanges of essential metabolites between individuals.
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Affiliation(s)
- Sébastien Halary
- Muséum National d'Histoire Naturelle, CNRS, UMR7245 Mécanismes de Communication et Adaptation des Micro-organismes, 12 rue Buffon, 75005, Paris, France.
| | - Sébastien Duperron
- Muséum National d'Histoire Naturelle, CNRS, UMR7245 Mécanismes de Communication et Adaptation des Micro-organismes, 12 rue Buffon, 75005, Paris, France
| | - Sandra Kim Tiam
- Muséum National d'Histoire Naturelle, CNRS, UMR7245 Mécanismes de Communication et Adaptation des Micro-organismes, 12 rue Buffon, 75005, Paris, France
- UMR5557 Laboratoire d'Ecologie Microbienne, Université de Lyon, 43 bd du 11 novembre 1918, Villeurbanne, F-69622, Lyon, France
| | - Charlotte Duval
- Muséum National d'Histoire Naturelle, CNRS, UMR7245 Mécanismes de Communication et Adaptation des Micro-organismes, 12 rue Buffon, 75005, Paris, France
| | - Cécile Bernard
- Muséum National d'Histoire Naturelle, CNRS, UMR7245 Mécanismes de Communication et Adaptation des Micro-organismes, 12 rue Buffon, 75005, Paris, France
| | - Benjamin Marie
- Muséum National d'Histoire Naturelle, CNRS, UMR7245 Mécanismes de Communication et Adaptation des Micro-organismes, 12 rue Buffon, 75005, Paris, France
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Ilicic D, Ionescu D, Woodhouse J, Grossart HP. Temperature-Related Short-Term Succession Events of Bacterial Phylotypes in Potter Cove, Antarctica. Genes (Basel) 2023; 14:genes14051051. [PMID: 37239412 DOI: 10.3390/genes14051051] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/03/2023] [Accepted: 05/04/2023] [Indexed: 05/28/2023] Open
Abstract
In recent years, our understanding of the roles of bacterial communities in the Antarctic Ocean has substantially improved. It became evident that Antarctic marine bacteria are metabolically versatile, and even closely related strains may differ in their functionality and, therefore, affect the ecosystem differently. Nevertheless, most studies have been focused on entire bacterial communities, with little attention given to individual taxonomic groups. Antarctic waters are strongly influenced by climate change; thus, it is crucial to understand how changes in environmental conditions, such as changes in water temperature and salinity fluctuations, affect bacterial species in this important area. In this study, we show that an increase in water temperature of 1 °C was enough to alter bacterial communities on a short-term temporal scale. We further show the high intraspecific diversity of Antarctic bacteria and, subsequently, rapid intra-species succession events most likely driven by various temperature-adapted phylotypes. Our results reveal pronounced changes in microbial communities in the Antarctic Ocean driven by a single strong temperature anomaly. This suggests that long-term warming may have profound effects on bacterial community composition and presumably functionality in light of continuous and future climate change.
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Affiliation(s)
- Doris Ilicic
- Department of Experimental Limnology, Leibniz Institute of Freshwater Ecology and Inland Fisheries, 16775 Neuglobsow, Germany
| | - Danny Ionescu
- Department of Experimental Limnology, Leibniz Institute of Freshwater Ecology and Inland Fisheries, 16775 Neuglobsow, Germany
| | - Jason Woodhouse
- Institut für Zoologie, Universität Hamburg, 20146 Hamburg, Germany
| | - Hans-Peter Grossart
- Department of Experimental Limnology, Leibniz Institute of Freshwater Ecology and Inland Fisheries, 16775 Neuglobsow, Germany
- Institute of Biochemistry and Biology, University of Potsdam, 14469 Potsdam, Germany
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Tanabe Y, Yamaguchi H, Yoshida M, Kai A, Okazaki Y. Characterization of a bloom-associated alphaproteobacterial lineage, 'Candidatus Phycosocius': insights into freshwater algal-bacterial interactions. ISME COMMUNICATIONS 2023; 3:20. [PMID: 36906708 PMCID: PMC10008586 DOI: 10.1038/s43705-023-00228-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 02/23/2023] [Accepted: 03/01/2023] [Indexed: 03/13/2023]
Abstract
Marine bacterial lineages associated with algal blooms, such as the Roseobacter clade, have been well characterized in ecological and genomic contexts, yet such lineages have rarely been explored in freshwater blooms. This study performed phenotypic and genomic analyses of an alphaproteobacterial lineage 'Candidatus Phycosocius' (denoted the CaP clade), one of the few lineages ubiquitously associated with freshwater algal blooms, and described a novel species: 'Ca. Phycosocius spiralis.' Phylogenomic analyses indicated that the CaP clade is a deeply branching lineage in the Caulobacterales. Pangenome analyses revealed characteristic features of the CaP clade: aerobic anoxygenic photosynthesis and essential vitamin B auxotrophy. Genome size varies widely among members of the CaP clade (2.5-3.7 Mb), likely a result of independent genome reductions at each lineage. This includes a loss of tight adherence pilus genes (tad) in 'Ca. P. spiralis' that may reflect its adoption of a unique spiral cell shape and corkscrew-like burrowing activity at the algal surface. Notably, quorum sensing (QS) proteins showed incongruent phylogenies, suggesting that horizontal transfers of QS genes and QS-involved interactions with specific algal partners might drive CaP clade diversification. This study elucidates the ecophysiology and evolution of proteobacteria associated with freshwater algal blooms.
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Affiliation(s)
- Yuuhiko Tanabe
- Biodiversity Division, National Institute for Environmental Studies, Ibaraki, 305-8506, Japan.
- Algae Biomass and Energy System R&D Center, University of Tsukuba, Ibaraki, 305-8572, Japan.
| | - Haruyo Yamaguchi
- Biodiversity Division, National Institute for Environmental Studies, Ibaraki, 305-8506, Japan
| | - Masaki Yoshida
- Algae Biomass and Energy System R&D Center, University of Tsukuba, Ibaraki, 305-8572, Japan
| | - Atsushi Kai
- Algae Biomass and Energy System R&D Center, University of Tsukuba, Ibaraki, 305-8572, Japan
| | - Yusuke Okazaki
- Institute for Chemical Research, Kyoto University, Kyoto, 611-0011, Japan
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11
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Effects of Phycosphere Bacteria on Their Algal Host Are Host Species-Specific and Not Phylogenetically Conserved. Microorganisms 2022; 11:microorganisms11010062. [PMID: 36677355 PMCID: PMC9862884 DOI: 10.3390/microorganisms11010062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 12/21/2022] [Accepted: 12/22/2022] [Indexed: 12/28/2022] Open
Abstract
Phytoplankton is fundamental to life on Earth. Their productivity is influenced by the microbial communities residing in the phycosphere surrounding algal cells. Expanding our knowledge on how algal-bacterial interactions affect algal growth to more hosts and bacteria can help elucidate general principles of algal-host interactions. Here, we isolated 368 bacterial strains from phycosphere communities, right after phycosphere recruitment from pond water and after a month of lab cultivation and examined their impacts on growth of five green algal species. We isolated both abundant and rare phycosphere members, representing 18.4% of the source communities. Positive and neutral effects predominated over negative effects on host growth. The proportion of each effect type and whether the day of isolation mattered varied by host species. Bacteria affected algal carrying capacity more than growth rate, suggesting that nutrient remineralization and toxic byproduct metabolism may be a dominant mechanism. Across-host algal fitness assays indicated host-specific growth effects of our isolates. We observed no phylogenetic conservation of the effect on host growth among bacterial isolates. Even isolates with the same ASV had divergent effects on host growth. Our results emphasize highly specific host-bacterial interactions in the phycosphere and raise questions as to which mechanisms mediate these interactions.
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12
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Reinl KL, Harris TD, Elfferich I, Coker A, Zhan Q, De Senerpont Domis LN, Morales-Williams AM, Bhattacharya R, Grossart HP, North RL, Sweetman JN. The role of organic nutrients in structuring freshwater phytoplankton communities in a rapidly changing world. WATER RESEARCH 2022; 219:118573. [PMID: 35643062 DOI: 10.1016/j.watres.2022.118573] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 04/27/2022] [Accepted: 05/07/2022] [Indexed: 06/15/2023]
Abstract
Carbon, nitrogen, and phosphorus are critical macroelements in freshwater systems. Historically, researchers and managers have focused on inorganic forms, based on the premise that the organic pool was not available for direct uptake by phytoplankton. We now know that phytoplankton can tap the organic nutrient pool through a number of mechanisms including direct uptake, enzymatic hydrolysis, mixotrophy, and through symbiotic relationships with microbial communities. In this review, we explore these mechanisms considering current and projected future anthropogenically-driven changes to freshwater systems. In particular, we focus on how naturally- and anthropogenically- derived organic nutrients can influence phytoplankton community structure. We also synthesize knowledge gaps regarding phytoplankton physiology and the potential challenges of nutrient management in an organically dynamic and anthropogenically modified world. Our review provides a basis for exploring these topics and suggests several avenues for future work on the relation between organic nutrients and eutrophication and their ecological implications in freshwater systems.
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Affiliation(s)
- Kaitlin L Reinl
- Lake Superior National Estuarine Research Reserve, University of Wisconsin-Madison Division of Extension, 14 Marina Drive, Superior, Wisconsin 54880, US; University of Wisconsin-Madison, Center for Limnology, 608 N. Park St., Madison, WI, US; University of Minnesota-Duluth, Large Lakes Observatory, 2205 E. 5th St., Duluth, MN, US.
| | - Ted D Harris
- Kansas Biological Survey and Center for Ecological Research, 2101 Constant Ave., Lawrence, KS, US
| | - Inge Elfferich
- Cardiff University, Earth and Environmental Sciences, Main Building, Park Place CF10 3AT, Cardiff, UK
| | - Ayooluwateso Coker
- University of Minnesota-Duluth, Large Lakes Observatory, 2205 E. 5th St., Duluth, MN, US
| | - Qing Zhan
- Netherlands Institute of Ecology, Dept. of Aquatic Ecology, Droevendaalsesteeg 10, Wageningen, NL
| | | | - Ana M Morales-Williams
- University of Vermont, Rubenstein School of Environment and Natural Resources, 81 Carrigan Drive, Burlington, VT, US
| | - Ruchi Bhattacharya
- University of Waterloo, Department of Earth and Environmental Sciences, 200 University Ave., N2L 1V6, Waterloo, ON, CA
| | - Hans-Peter Grossart
- Leibniz Institute for Freshwater Ecology and Inland Fisheries (IGB), Dept. Plankton and Microbial Ecology, Zur alten Fischerhuette 2, D-16775 Stechlin, DE; Potsdam University, Institute of Biochemistry and Biology, Maulbeerallee 2, 14469 Potsdam
| | - Rebecca L North
- University of Missouri-Columbia, School of Natural Resources, 303L Anheuser Busch Natural Resource Building, Columbia, MO, US
| | - Jon N Sweetman
- Pennsylvania State University, Ecological Science and Management, 457 Agriculture Sciences and Industries Building, State College, PA, US
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13
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Sanseverino I, Pretto P, António DC, Lahm A, Facca C, Loos R, Skejo H, Beghi A, Pandolfi F, Genoni P, Lettieri T. Metagenomics Analysis to Investigate the Microbial Communities and Their Functional Profile During Cyanobacterial Blooms in Lake Varese. MICROBIAL ECOLOGY 2022; 83:850-868. [PMID: 34766210 PMCID: PMC9016052 DOI: 10.1007/s00248-021-01914-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 10/26/2021] [Indexed: 05/09/2023]
Abstract
Toxic cyanobacterial blooms represent a natural phenomenon caused by a mass proliferation of photosynthetic prokaryotic microorganisms in water environments. Bloom events have been increasingly reported worldwide and their occurrence can pose serious threats to aquatic organisms and human health. In this study, we assessed the microbial composition, with a focus on Cyanobacteria, in Lake Varese, a eutrophic lake located in northern Italy. Water samples were collected and used for obtaining a 16S-based taxonomic profile and performing a shotgun sequencing analysis. The phyla found to exhibit the greatest relative abundance in the lake included Proteobacteria, Cyanobacteria, Actinobacteriota and Bacteroidota. In the epilimnion and at 2.5 × Secchi depth, Cyanobacteria were found to be more abundant compared to the low levels detected at greater depths. The blooms appear to be dominated mainly by the species Lyngbya robusta, and a specific functional profile was identified, suggesting that distinct metabolic processes characterized the bacterial population along the water column. Finally, analysis of the shotgun data also indicated the presence of a large and diverse phage population.
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Affiliation(s)
- Isabella Sanseverino
- European Commission, Joint Research Centre (JRC), Via E. Fermi 2749, 21027, Ispra, VA, Italy
| | - Patrizia Pretto
- Biosearch Ambiente Srl, Via Tetti Gai 59, 10091, Alpignano, TO, Italy
| | - Diana Conduto António
- European Commission, Joint Research Centre (JRC), Via E. Fermi 2749, 21027, Ispra, VA, Italy
| | - Armin Lahm
- Bioinformatics Project Support, P.za S.M. Liberatrice 18, 00153, Roma, Italy
| | - Chiara Facca
- Department of Environmental Science, Informatics and Statistics, University Ca' Foscari Venezia, Via Torino 155, 301702, Mestre, VE, Italy
| | - Robert Loos
- European Commission, Joint Research Centre (JRC), Via E. Fermi 2749, 21027, Ispra, VA, Italy
| | - Helle Skejo
- European Commission, Joint Research Centre (JRC), Via E. Fermi 2749, 21027, Ispra, VA, Italy
| | - Andrea Beghi
- ARPA, Agenzia Regionale Per La Protezione Dell'Ambiente Della Lombardia, Via Ippolito Rosellini 17, 20124, Milano, Italy
| | - Franca Pandolfi
- ARPA, Agenzia Regionale Per La Protezione Dell'Ambiente Della Lombardia, Via Ippolito Rosellini 17, 20124, Milano, Italy
| | - Pietro Genoni
- ARPA, Agenzia Regionale Per La Protezione Dell'Ambiente Della Lombardia, Via Ippolito Rosellini 17, 20124, Milano, Italy
| | - Teresa Lettieri
- European Commission, Joint Research Centre (JRC), Via E. Fermi 2749, 21027, Ispra, VA, Italy.
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14
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Gobler CJ, Jankowiak JG. Dynamic Responses of Endosymbiotic Microbial Communities Within Microcystis Colonies in North American Lakes to Altered Nitrogen, Phosphorus, and Temperature Levels. Front Microbiol 2022; 12:781500. [PMID: 35222297 PMCID: PMC8867038 DOI: 10.3389/fmicb.2021.781500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 11/23/2021] [Indexed: 11/29/2022] Open
Abstract
The toxic cyanobacterium, Microcystis, is a pervasive cyanobacterial harmful algal bloom (CHAB) - forming genus that naturally occurs in colonies that harbor diverse microbiomes of heterotrophic bacteria. While the effects of nutrient loading and climatic warming on CHABs are well-known, little is known regarding how these environmental drivers alter the structural and functional potential of the microbial assemblages associated with blooms that, in turn, may impact cyanobacterial growth. Here, we used next-generation sequencing of 16S ribosomal rRNA genes to characterize the dynamics of the bacterial assemblages within Microcystis colonies in two temperate North American lakes: Lake Erie and Lake Agawam (NY, United States) and quantified their responses to experimentally increased levels of nitrogen (N), phosphorus (P) and temperature. Across experiments, Microcystis populations were consistently and significantly promoted by N and, to a lesser extent, elevated temperature (p < 0.05). In contrast, bacterial assemblages within Microcystis colonies were more resilient to environmental perturbations, with the relative abundance of 7–16% of amplicon sequence variants changing and several individual taxa displaying significant (p < 0.05) increases and decreases in relative abundance, primarily in response to elevated temperature and to a lesser extent, N. In contrast to individual taxa, community diversity was not significantly altered by individual treatments during experiments but rather was inversely correlated with the intensity of Microcystis blooms (p < 0.001). While predicted metabolic function was even less impacted by environmental drivers than microbial diversity, the predicted abundance of nitrogenase (nifH), alkaline phosphatase (phoX), and urease (ure) genes significantly increased in response to N but decreased in response to increased temperature (p < 0.05). Collectively, the resilience of microbial community structure and function within colonies suggests they may support the ability of Microcystis to persist through short-term fluctuations in environmental conditions by supplying essential nutrients.
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15
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Gann ER, Truchon AR, Papoulis SE, Dyhrman ST, Gobler CJ, Wilhelm SW. Aureococcus anophagefferens (Pelagophyceae) genomes improve evaluation of nutrient acquisition strategies involved in brown tide dynamics. JOURNAL OF PHYCOLOGY 2022; 58:146-160. [PMID: 34773248 DOI: 10.1111/jpy.13221] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 10/29/2021] [Accepted: 11/02/2021] [Indexed: 06/13/2023]
Abstract
The pelagophyte Aureococcus anophagefferens causes harmful brown tide blooms in marine embayments on three continents. Aureococcus anophagefferens was the first harmful algal bloom species to have its genome sequenced, an advance that evidenced genes important for adaptation to environmental conditions that prevail during brown tides. To expand the genomic tools available for this species, genomes for four strains were assembled, including three newly sequenced strains and one assembled from publicly available data. These genomes ranged from 57.11 to 73.62 Mb, encoding 13,191-17,404 potential proteins. All strains shared ~90% of their encoded proteins as determined by homology searches and shared most functional orthologs as determined by KEGG, although each strain also possessed coding sequences with unique functions. Like the original reference genome, the genomes assembled in this study possessed genes hypothesized to be important in bloom proliferation, including genes involved in organic compound metabolism and growth at low light. Cross-strain informatics and culture experiments suggest that the utilization of purines is a potentially important source of organic nitrogen for brown tides. Analyses of metatranscriptomes from a brown tide event demonstrated that use of a single genome yielded a lower read mapping percentage (~30% of library reads) as compared to a database generated from all available genomes (~43%), suggesting novel information about bloom ecology can be gained from expanding genomic space. This work demonstrates the continued need to sequence ecologically relevant algae to understand the genomic potential and their ecology in the environment.
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Affiliation(s)
- Eric R Gann
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - Alexander R Truchon
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - Spiridon E Papoulis
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - Sonya T Dyhrman
- Biology and Paleo Environment Division, Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York, 10964, USA
- Department of Earth and Environmental Sciences, Columbia University, Palisades, New York, 10964, USA
| | - Christopher J Gobler
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York, 11790, USA
| | - Steven W Wilhelm
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, 37996, USA
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16
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Pérez-Carrascal OM, Tromas N, Terrat Y, Moreno E, Giani A, Corrêa Braga Marques L, Fortin N, Shapiro BJ. Single-colony sequencing reveals microbe-by-microbiome phylosymbiosis between the cyanobacterium Microcystis and its associated bacteria. MICROBIOME 2021; 9:194. [PMID: 34579777 PMCID: PMC8477515 DOI: 10.1186/s40168-021-01140-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 08/02/2021] [Indexed: 05/26/2023]
Abstract
BACKGROUND Cyanobacteria from the genus Microcystis can form large mucilaginous colonies with attached heterotrophic bacteria-their microbiome. However, the nature of the relationship between Microcystis and its microbiome remains unclear. Is it a long-term, evolutionarily stable association? Which partners benefit? Here we report the genomic diversity of 109 individual Microcystis colonies-including cyanobacteria and associated bacterial genomes-isolated in situ and without culture from Lake Champlain, Canada and Pampulha Reservoir, Brazil. RESULTS We identified 14 distinct Microcystis genotypes from Canada, of which only two have been previously reported, and four genotypes specific to Brazil. Microcystis genetic diversity was much greater between than within colonies, consistent with colony growth by clonal expansion rather than aggregation of Microcystis cells. We also identified 72 bacterial species in the microbiome. Each Microcystis genotype had a distinct microbiome composition, and more closely related genotypes had more similar microbiomes. This pattern of phylosymbiosis could be explained by co-phylogeny in only two out of the nine most prevalent associated bacterial genera, Roseomonas and Rhodobacter. These phylogenetically associated genera could enrich the metabolic repertoire of Microcystis, for example by encoding the biosynthesis of complementary carotenoid molecules. In contrast, other colony-associated bacteria showed weaker signals of co-phylogeny, but stronger evidence of horizontal gene transfer with Microcystis. These observations suggest that acquired genes are more likely to be retained in both partners (Microcystis and members of its microbiome) when they are loosely associated, whereas one gene copy is sufficient when the association is physically tight and evolutionarily long-lasting. CONCLUSIONS We have introduced a method for culture-free isolation of single colonies from nature followed by metagenomic sequencing, which could be applied to other types of microbes. Together, our results expand the known genetic diversity of both Microcystis and its microbiome in natural settings, and support their long-term, specific, and potentially beneficial associations. Video Abstract.
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Affiliation(s)
| | - Nicolas Tromas
- Département de Sciences Biologiques, Université́ de Montréal, Montréal, Québec, Canada.
| | - Yves Terrat
- Département de Sciences Biologiques, Université́ de Montréal, Montréal, Québec, Canada
| | - Elisa Moreno
- Département de Sciences Biologiques, Université́ de Montréal, Montréal, Québec, Canada
| | - Alessandra Giani
- Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | | | - Nathalie Fortin
- National Research Council of Canada, Montreal, Québec, Canada
| | - B Jesse Shapiro
- Département de Sciences Biologiques, Université́ de Montréal, Montréal, Québec, Canada.
- Department of Microbiology & Immunology, McGill University, Montreal, Québec, Canada.
- McGill Genome Centre, McGill University, Montreal, Québec, Canada.
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17
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Dick GJ, Duhaime MB, Evans JT, Errera RM, Godwin CM, Kharbush JJ, Nitschky HS, Powers MA, Vanderploeg HA, Schmidt KC, Smith DJ, Yancey CE, Zwiers CC, Denef VJ. The genetic and ecophysiological diversity of Microcystis. Environ Microbiol 2021; 23:7278-7313. [PMID: 34056822 DOI: 10.1111/1462-2920.15615] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 05/24/2021] [Accepted: 05/27/2021] [Indexed: 01/30/2023]
Abstract
Microcystis is a cyanobacterium that forms toxic blooms in freshwater ecosystems around the world. Biological variation among taxa within the genus is apparent through genetic and phenotypic differences between strains and via the spatial and temporal distribution of strains in the environment, and this fine-scale diversity exerts strong influence over bloom toxicity. Yet we do not know how varying traits of Microcystis strains govern their environmental distribution, the tradeoffs and links between these traits, or how they are encoded at the genomic level. Here we synthesize current knowledge on the importance of diversity within Microcystis and on the genes and traits that likely underpin ecological differentiation of taxa. We briefly review spatial and environmental patterns of Microcystis diversity in the field and genetic evidence for cohesive groups within Microcystis. We then compile data on strain-level diversity regarding growth responses to environmental conditions and explore evidence for variation of community interactions across Microcystis strains. Potential links and tradeoffs between traits are identified and discussed. The resulting picture, while incomplete, highlights key knowledge gaps that need to be filled to enable new models for predicting strain-level dynamics, which influence the development, toxicity and cosmopolitan nature of Microcystis blooms.
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Affiliation(s)
- Gregory J Dick
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA.,Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Melissa B Duhaime
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Jacob T Evans
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Reagan M Errera
- National Oceanographic and Atmospheric Administration Great Lakes Environmental Research Lab, Ann Arbor, MI, USA
| | - Casey M Godwin
- School for Environment and Sustainability, Cooperative Institute for Great Lakes Research, University of Michigan, Ann Arbor, MI, USA
| | - Jenan J Kharbush
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Helena S Nitschky
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - McKenzie A Powers
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Henry A Vanderploeg
- National Oceanographic and Atmospheric Administration Great Lakes Environmental Research Lab, Ann Arbor, MI, USA
| | - Kathryn C Schmidt
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Derek J Smith
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Colleen E Yancey
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Claire C Zwiers
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Vincent J Denef
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
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18
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Smith DJ, Tan JY, Powers MA, Lin XN, Davis TW, Dick GJ. Individual Microcystis colonies harbour distinct bacterial communities that differ by Microcystis oligotype and with time. Environ Microbiol 2021; 23:3020-3036. [PMID: 33830633 DOI: 10.1111/1462-2920.15514] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 03/11/2021] [Accepted: 04/06/2021] [Indexed: 12/31/2022]
Abstract
Interactions between bacteria and phytoplankton in the phycosphere have impacts at the scale of whole ecosystems, including the development of harmful algal blooms. The cyanobacterium Microcystis causes toxic blooms that threaten freshwater ecosystems and human health globally. Microcystis grows in colonies that harbour dense assemblages of other bacteria, yet the taxonomic composition of these phycosphere communities and the nature of their interactions with Microcystis are not well characterized. To identify the taxa and compositional variance within Microcystis phycosphere communities, we performed 16S rRNA V4 region amplicon sequencing on individual Microcystis colonies collected biweekly via high-throughput droplet encapsulation during a western Lake Erie cyanobacterial bloom. The Microcystis phycosphere communities were distinct from microbial communities in whole water and bulk phytoplankton seston in western Lake Erie but lacked 'core' taxa found across all colonies. However, dissimilarity in phycosphere community composition correlated with sampling date and the Microcystis 16S rRNA oligotype. Several taxa in the phycosphere were specific to and conserved with Microcystis of a single oligotype or sampling date. Together, this suggests that physiological differences between Microcystis strains, temporal changes in strain phenotypes, and the composition of seeding communities may impact community composition of the Microcystis phycosphere.
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Affiliation(s)
- Derek J Smith
- Department of Earth & Environmental Science, The University of Michigan, 1100 N. University Building, 1100 N. University Avenue, Ann Arbor, MI, 48109, USA
| | - James Y Tan
- Department of Chemical Engineering, The University of Michigan, NCRC, 2800 Plymouth Rd., Ann Abor, MI, 48109, USA
| | - McKenzie A Powers
- Department of Earth & Environmental Science, The University of Michigan, 1100 N. University Building, 1100 N. University Avenue, Ann Arbor, MI, 48109, USA
| | - Xiaoxia N Lin
- Department of Chemical Engineering, The University of Michigan, NCRC, 2800 Plymouth Rd., Ann Abor, MI, 48109, USA
| | - Timothy W Davis
- Department of Biological Sciences, Bowling Green State University, Life Sciences Building, Corner of N. College Dr and E. Merry Avenue, Bowling Green, OH, 43403, USA
| | - Gregory J Dick
- Department of Earth & Environmental Science, The University of Michigan, 1100 N. University Building, 1100 N. University Avenue, Ann Arbor, MI, 48109, USA
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19
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Durán-Vinet B, Araya-Castro K, Chao TC, Wood SA, Gallardo V, Godoy K, Abanto M. Potential applications of CRISPR/Cas for next-generation biomonitoring of harmful algae blooms: A review. HARMFUL ALGAE 2021; 103:102027. [PMID: 33980455 DOI: 10.1016/j.hal.2021.102027] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 03/01/2021] [Accepted: 03/21/2021] [Indexed: 06/12/2023]
Abstract
Research on harmful algal and cyanobacterial blooms (HABs and CHABs) has risen dramatically due to their increasing global distribution, frequency, and intensity. These blooms jeopardize public health, ecosystem function, sustainability and can have negative economic impacts. Numerous monitoring programs have been established using light microscopy, liquid chromatography coupled to mass spectrometry (LC-MS), ELISA, and spectrophotometry to monitor HABs/CHABs outbreaks. Recently, DNA/RNA-based molecular methods have been integrated into these programs to replace or complement traditional methods through analyzing environmental DNA and RNA (eDNA/eRNA) with techniques such as quantitative polymerase chain reaction (qPCR), fluorescent in situ hybridization (FISH), sandwich hybridization assay (SHA), isothermal amplification methods, and microarrays. These have enabled the detection of rare or cryptic species, enhanced sample throughput, and reduced costs and the need for visual taxonomic expertise. However, these methods have limitations, such as the need for high capital investment in equipment or detection uncertainties, including determining whether organisms are viable. In this review, we discuss the potential of newly developed molecular diagnosis technology based on Clustered Regularly Interspaced Short Palindromic Repeats/Cas proteins (CRISPR/Cas), which utilizes the prokaryotic adaptative immune systems of bacteria and archaea. Cas12 and Cas13-based platforms can detect both DNA and RNA with attomolar sensitivity within an hour. CRISPR/Cas diagnostic is a rapid, inexpensive, specific, and ultrasensitive technology that, with some further development, will provide many new platforms that can be used for HABs/CHABs biomonitoring and research.
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Affiliation(s)
- B Durán-Vinet
- Scientific and Technological Bioresource Nucleus (BIOREN-UFRO), Genomics and Bioinformatics Unit, Universidad de La Frontera, Av. Francisco Salazar, 1145 Temuco, Chile; Bachelor of Biotechnology (Honours) Program, Faculty of Agricultural and Forestry Sciences, Universidad de La Frontera, Av. Francisco Salazar, 1145 Temuco, Chile.
| | - K Araya-Castro
- Doctoral Program in Science of Natural Resources, Universidad de La Frontera, Av. Francisco Salazar, 1145 Temuco, Chile
| | - T C Chao
- Institute of Environmental Change & Society, Department of Biology, University of Regina, Wascana Parkway, 3737 Regina, Canada
| | - S A Wood
- Coastal and Freshwater Group, Cawthron Institute, 98 Halifax Street East, Nelson 7010, New Zealand
| | - V Gallardo
- Scientific and Technological Bioresource Nucleus (BIOREN-UFRO), Genomics and Bioinformatics Unit, Universidad de La Frontera, Av. Francisco Salazar, 1145 Temuco, Chile; Bachelor of Biotechnology (Honours) Program, Faculty of Agricultural and Forestry Sciences, Universidad de La Frontera, Av. Francisco Salazar, 1145 Temuco, Chile
| | - K Godoy
- Scientific and Technological Bioresource Nucleus (BIOREN-UFRO), Microscopy and Flow Cytometry Unit, Universidad de La Frontera, Av. Francisco Salazar, 1145 Temuco, Chile
| | - M Abanto
- Scientific and Technological Bioresource Nucleus (BIOREN-UFRO), Genomics and Bioinformatics Unit, Universidad de La Frontera, Av. Francisco Salazar, 1145 Temuco, Chile
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20
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Jackrel SL, Yang JW, Schmidt KC, Denef VJ. Host specificity of microbiome assembly and its fitness effects in phytoplankton. THE ISME JOURNAL 2021; 15:774-788. [PMID: 33097853 PMCID: PMC8027036 DOI: 10.1038/s41396-020-00812-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 10/05/2020] [Accepted: 10/09/2020] [Indexed: 12/21/2022]
Abstract
Insights into symbiosis between eukaryotic hosts and their microbiomes have shifted paradigms on what determines host fitness, ecology, and behavior. Questions remain regarding the roles of host versus environment in shaping microbiomes, and how microbiome composition affects host fitness. Using a model system in ecology, phytoplankton, we tested whether microbiomes are host-specific, confer fitness benefits that are host-specific, and remain conserved in time in their composition and fitness effects. We used an experimental approach in which hosts were cleaned of bacteria and then exposed to bacterial communities from natural environments to permit recruitment of microbiomes. We found that phytoplankton microbiomes consisted of a subset of taxa recruited from these natural environments. Microbiome recruitment was host-specific, with host species explaining more variation in microbiome composition than environment. While microbiome composition shifted and then stabilized over time, host specificity remained for dozens of generations. Microbiomes increased host fitness, but these fitness effects were host-specific for only two of the five species. The shifts in microbiome composition over time amplified fitness benefits to the hosts. Overall, this work solidifies the importance of host factors in shaping microbiomes and elucidates the temporal dynamics of microbiome compositional and fitness effects.
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Affiliation(s)
- Sara L Jackrel
- Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA.
- Ecology, Behavior and Evolution Section, University of California San Diego, La Jolla, CA, USA.
| | - Jinny W Yang
- Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Kathryn C Schmidt
- Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Vincent J Denef
- Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA.
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21
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Schmidt KC, Jackrel SL, Smith DJ, Dick GJ, Denef VJ. Genotype and host microbiome alter competitive interactions between Microcystis aeruginosa and Chlorella sorokiniana. HARMFUL ALGAE 2020; 99:101939. [PMID: 33218432 DOI: 10.1016/j.hal.2020.101939] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 10/15/2020] [Accepted: 10/26/2020] [Indexed: 05/24/2023]
Abstract
Cyanobacterial harmful algal blooms (cyanoHABs) continue to increase in frequency and magnitude, threatening global freshwater ecosystems and services. In north-temperate lakes cyanobacteria appear in early summer, succeeding green algae as the dominant phytoplankton group, a pattern thought to be mediated by changes in temperature and bioavailable nutrients. To understand additional drivers of this successional pattern our study used reciprocal invasion experiments to examine the competitive interaction between Microcystis aeruginosa, a dominant contributor to cyanoHABs, and the green alga Chlorella sorokiniana. We considered two factors that may impact these interactions: (1) strain variation, with a specific emphasis on the presence or absence of the gene for the hepatotoxin microcystin, and (2) host-associated bacteria. We used toxic M. aeruginosa PCC 7806 (microcystin producing strain), a non-toxic mutant of PCC 7806, non-toxic M. aeruginosa PCC 9701 (non-microcystin producing strain), and C. sorokiniana. Each organism was available free of all bacteria (i.e., axenic) and with a re-introduced defined bacterial community to generate their xenic counterparts. Competitive interactions were assessed with reciprocal invasion experiments between paired xenic and paired axenic populations of C. sorokiniana and one of the two Microcystis strains, each assessed separately. Flow cytometry and random forest models were used to rapidly discriminate and quantify phytoplankton population densities with 99% accuracy. We found that M. aeruginosa PCC 7806, but not strain PCC 9701, could proliferate from low abundance in a steady-state population of C. sorokiniana. Further, the presence of bacteria allowed M. aeruginosa PCC 7806 to grow to a higher population density into an established C. sorokiniana population than when grown axenic. Conversely, when M. aeruginosa was dominant, C. sorokiniana was only able to proliferate from low density into the PCC 9701 strain, and only when axenic. The mutant of PCC 7806 lacking the ability to produce microcystin behaved similarly to the toxic wild-type, implying microcystin is not responsible for the difference in competitive abilities observed between the two wild-type strains. Quantification of microcystins (MCs) when PCC 7806 M. aeruginosa was introduced into the C. sorokiniana culture showed two-fold more MCs per cell when host-associated bacteria were absent compared to present in both species cultures. Our results show that the ability of M. aeruginosa to compete with C. sorokiniana is determined by genomic differences beyond genes involved in microcystin toxin generation and indicate an important role of host-associated bacteria in mediating phytoplankton interspecies interactions. These results expand our understanding of the key drivers of phytoplankton succession and the establishment and persistence of freshwater harmful cyanobacterial blooms.
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Affiliation(s)
- Kathryn C Schmidt
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sara L Jackrel
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Derek J Smith
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, USA
| | - Gregory J Dick
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA; Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, USA
| | - Vincent J Denef
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA.
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22
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Abstract
Metagenome-assembled genomes (MAGs) expand our understanding of microbial diversity, evolution, and ecology. Concerns have been raised on how sequencing, assembly, binning, and quality assessment tools may result in MAGs that do not reflect single populations in nature. Here, we reflect on another issue, i.e., how to handle highly similar MAGs assembled from independent data sets. Obtaining multiple genomic representatives for a species is highly valuable, as it allows for population genomic analyses; however, when retaining genomes of closely related populations, it complicates MAG quality assessment and abundance inferences. Metagenome-assembled genomes (MAGs) expand our understanding of microbial diversity, evolution, and ecology. Concerns have been raised on how sequencing, assembly, binning, and quality assessment tools may result in MAGs that do not reflect single populations in nature. Here, we reflect on another issue, i.e., how to handle highly similar MAGs assembled from independent data sets. Obtaining multiple genomic representatives for a species is highly valuable, as it allows for population genomic analyses; however, when retaining genomes of closely related populations, it complicates MAG quality assessment and abundance inferences. We show that (i) published data sets contain a large fraction of MAGs sharing >99% average nucleotide identity, (ii) different software packages and parameters used to resolve this redundancy remove very different numbers of MAGs, and (iii) the removal of closely related genomes leads to losses of population-specific auxiliary genes. Finally, we highlight some approaches that can infer strain-specific dynamics across a sample series without dereplication.
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23
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Temperature and Nutrient Levels Correspond with Lineage-Specific Microdiversification in the Ubiquitous and Abundant Freshwater Genus Limnohabitans. Appl Environ Microbiol 2020; 86:AEM.00140-20. [PMID: 32169939 DOI: 10.1128/aem.00140-20] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 03/10/2020] [Indexed: 11/20/2022] Open
Abstract
Most freshwater bacterial communities are characterized by a few dominant taxa that are often ubiquitous across freshwater biomes worldwide. Our understanding of the genomic diversity within these taxonomic groups is limited to a subset of taxa. Here, we investigated the genomic diversity that enables Limnohabitans, a freshwater genus key in funneling carbon from primary producers to higher trophic levels, to achieve abundance and ubiquity. We reconstructed eight putative Limnohabitans metagenome-assembled genomes (MAGs) from stations located along broad environmental gradients existing in Lake Michigan, part of Earth's largest surface freshwater system. De novo strain inference analysis resolved a total of 23 strains from these MAGs, which strongly partitioned into two habitat-specific clusters with cooccurring strains from different lineages. The largest number of strains belonged to the abundant LimB lineage, for which robust in situ strain delineation had not previously been achieved. Our data show that temperature and nutrient levels may be important environmental parameters associated with microdiversification within the Limnohabitans genus. In addition, strains predominant in low- and high-phosphorus conditions had larger genomic divergence than strains abundant under different temperatures. Comparative genomics and gene expression analysis yielded evidence for the ability of LimB populations to exhibit cellular motility and chemotaxis, a phenotype not yet associated with available Limnohabitans isolates. Our findings broaden historical marker gene-based surveys of Limnohabitans microdiversification and provide in situ evidence of genome diversity and its functional implications across freshwater gradients.IMPORTANCE Limnohabitans is an important bacterial taxonomic group for cycling carbon in freshwater ecosystems worldwide. Here, we examined the genomic diversity of different Limnohabitans lineages. We focused on the LimB lineage of this genus, which is globally distributed and often abundant, and its abundance has shown to be largely invariant to environmental change. Our data show that the LimB lineage is actually comprised of multiple cooccurring populations for which the composition and genomic characteristics are associated with variations in temperature and nutrient levels. The gene expression profiles of this lineage suggest the importance of chemotaxis and motility, traits that had not yet been associated with the Limnohabitans genus, in adapting to environmental conditions.
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24
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Jackrel SL, Schmidt KC, Cardinale BJ, Denef VJ. Microbiomes Reduce Their Host's Sensitivity to Interspecific Interactions. mBio 2020; 11:e02657-19. [PMID: 31964727 PMCID: PMC6974562 DOI: 10.1128/mbio.02657-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 12/10/2019] [Indexed: 01/01/2023] Open
Abstract
Bacteria associated with eukaryotic hosts can affect host fitness and trophic interactions between eukaryotes, but the extent to which bacteria influence the eukaryotic species interactions within trophic levels that modulate biodiversity and species coexistence is mostly unknown. Here, we used phytoplankton, which are a classic model for evaluating interactions between species, grown with and without associated bacteria to test whether the bacteria alter the strength and type of species interactions within a trophic level. We demonstrate that host-associated bacteria alter host growth rates and carrying capacity. This did not change the type but frequently changed the strength of host interspecific interactions by facilitating host growth in the presence of an established species. These findings indicate that microbiomes can regulate their host species' interspecific interactions. As between-species interaction strength impacts their ability to coexist, our findings show that microbiomes have the potential to modulate eukaryotic species diversity and community composition.IMPORTANCE Description of the Earth's microbiota has recently undergone a phenomenal expansion that has challenged basic assumptions in many areas of biology, including hominid evolution, human gastrointestinal and neurodevelopmental disorders, and plant adaptation to climate change. By using the classic model system of freshwater phytoplankton that has been drawn upon for numerous foundational theories in ecology, we show that microbiomes, by facilitating their host population, can also influence between-species interactions among their eukaryotic hosts. Between-species interactions, including competition for resources, has been a central tenet in the field of ecology because of its implications for the diversity and composition of communities and how this in turn shapes ecosystem functioning.
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Affiliation(s)
- Sara L Jackrel
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Kathryn C Schmidt
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Bradley J Cardinale
- School for Environment and Sustainability, University of Michigan, Ann Arbor, Michigan, USA
- Cooperative Institute for Great Lakes Research, University of Michigan, Ann Arbor, Michigan, USA
| | - Vincent J Denef
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, USA
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