Genome Streamlining, Plasticity, and Metabolic Versatility Distinguish Co-occurring Toxic and Nontoxic Cyanobacterial Strains of <i>Microcoleus</i>.

Show simple item record Tee, Hwee Sze Wood, Susanna A Bouma-Gregson, Keith Lear, Gavin Handley, Kim M
dc.coverage.spatial United States 2022-05-23T03:19:05Z 2022-05-23T03:19:05Z 2021-10-26
dc.identifier.citation (2021). mBio, 12(5), e0223521-.
dc.identifier.issn 2150-7511
dc.description.abstract Harmful cyanobacterial bloom occurrences have increased worldwide due to climate change and eutrophication, causing nuisance and animal deaths. Species from the benthic cyanobacterial genus <i>Microcoleus</i> are ubiquitous and form thick mats in freshwater systems, such as rivers, that are sometimes toxic due to the production of potent neurotoxins (anatoxins). Anatoxin-producing (toxic) strains typically coexist with non-anatoxin-producing (nontoxic) strains in mats, although the reason for this is unclear. To determine the genetic mechanisms differentiating toxic and nontoxic <i>Microcoleus</i>, we sequenced and assembled genomes from 11 cultures and compared these to another 31 <i>Microcoleus</i> genomes. Average nucleotide identities (ANI) indicate that toxic and nontoxic strains are distinct species (ANI, <95%), and only 6% of genes are shared across all 42 genomes, suggesting a high level of genetic divergence among <i>Microcoleus</i> strains. Comparative genomics showed substantial genome streamlining in toxic strains and a potential dependency on external sources for thiamine and sucrose. Toxic and nontoxic strains are further differentiated by an additional set of putative nitrate transporter (nitrogen uptake) and cyanophycin (carbon and nitrogen storage) genes, respectively. These genes likely confer distinct competitive advantages based on nutrient availability and suggest nontoxic strains are more robust to nutrient fluctuations. Nontoxic strains also possess twice as many transposable elements, potentially facilitating greater genetic adaptation to environmental changes. Our results offer insights into the divergent evolution of <i>Microcoleus</i> strains and the potential for cooperative and competitive interactions that contribute to the co-occurrence of toxic and nontoxic species within mats. <b>IMPORTANCE</b> Microcoleus autumnalis, and closely related <i>Microcoleus</i> species, compose a geographically widespread group of freshwater benthic cyanobacteria. Canine deaths due to anatoxin-a poisoning, following exposure to toxic proliferations, have been reported globally. While <i>Microcoleus</i> proliferations are on the rise, the mechanisms underpinning competition between, or coexistence of, toxic and nontoxic strains are unknown. This study identifies substantial genetic differences between anatoxin-producing and non-anatoxin-producing strains, pointing to reduced metabolic flexibility in toxic strains, and potential dependence on cohabiting nontoxic strains. Results provide insights into the metabolic and evolutionary differences between toxic and nontoxic <i>Microcoleus</i>, which may assist in predicting and managing aquatic proliferations.
dc.format.medium Print-Electronic
dc.language eng
dc.publisher American Society for Microbiology
dc.relation.ispartofseries mBio
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher.
dc.subject Cyanobacteria
dc.subject Nitrogen
dc.subject Bacterial Proteins
dc.subject DNA Transposable Elements
dc.subject Bacterial Toxins
dc.subject Rivers
dc.subject Phylogeny
dc.subject Genome, Bacterial
dc.subject Genome Size
dc.subject Nitrate Transporters
dc.subject Phormidium autumnale
dc.subject anatoxins
dc.subject benthic cyanobacteria
dc.subject comparative genomics
dc.subject cyanobacterial proliferation
dc.subject resource trade-off
dc.subject toxic and nontoxic cyanobacteria
dc.subject Genetics
dc.subject Human Genome
dc.subject Biotechnology
dc.subject Science & Technology
dc.subject Life Sciences & Biomedicine
dc.subject Microbiology
dc.subject ANATOXIN-A
dc.subject ECOLOGY
dc.subject VARIABILITY
dc.subject ALGORITHM
dc.subject EVOLUTION
dc.subject TAXONOMY
dc.subject 0605 Microbiology
dc.title Genome Streamlining, Plasticity, and Metabolic Versatility Distinguish Co-occurring Toxic and Nontoxic Cyanobacterial Strains of <i>Microcoleus</i>.
dc.type Journal Article
dc.identifier.doi 10.1128/mbio.02235-21
pubs.issue 5
pubs.begin-page e0223521
pubs.volume 12 2022-04-11T21:29:16Z
dc.rights.holder Copyright: The author en
dc.identifier.pmid 34700377 (pubmed)
pubs.publication-status Published
dc.rights.accessrights en
pubs.subtype Research Support, Non-U.S. Gov't
pubs.subtype research-article
pubs.subtype Journal Article
pubs.elements-id 871149 Science Biological Sciences
dc.identifier.eissn 2150-7511
pubs.number ARTN e02235-21
pubs.record-created-at-source-date 2022-04-12

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