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Deng Z, Yang W, Lin T, Wang Y, Hua X, Jiang X, Chen J, Liu D, Ye Z, Zhang Y, Lynch M, Long H, Pan J. Multidimensional insights into the biodiversity of Streptomyces in soils of China: a pilot study. Microbiol Spectr 2025; 13:e0169224. [PMID: 40172189 PMCID: PMC12054067 DOI: 10.1128/spectrum.01692-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2024] [Accepted: 02/11/2025] [Indexed: 04/04/2025] Open
Abstract
Streptomyces, a diverse group of filamentous bacteria found predominantly in soil, play a crucial role in nutrient cycling and produce many valuable secondary metabolites for the pharmaceutical industry. In this pilot study, we collected 19 soil samples from 14 provinces in China to preliminarily investigate the biodiversity and genetic structure of Streptomyces in soils of China from different dimensions, using recently developed cost-efficient amplicon and whole-genome library preparation methods. Amplicon analysis showed that Actinobacteria were among the most abundant bacteria, with 0.3% of amplicon sequence variants (ASVs) belonging to Streptomyces. Meanwhile, we successfully isolated 136 Streptomyces natural strains and assembled their genomes, including 26 previously unreported species, underscoring the need for further exploration of soil Streptomyces in China. Population genetics analysis revealed that homologous recombination may primarily drive the extensive genetic diversity observed in Streptomyces, as well as a complex population structure. Complementing this, pan-genome analysis shed light on gene diversity within Streptomyces and led to the discovery of rare genes, further emphasizing the vast genetic diversity of this genus. Additionally, multiple metabolic gene clusters were found in these Streptomyces strains, as well as some potentially unique or uncommon ones were found. These findings not only highlight the biological and metabolic diversity of Streptomyces but also provide a technical framework for future studies on the global biodiversity and evolution of this genus. IMPORTANCE Streptomyces, a prominent group of Actinobacteria, holds significant importance in ecosystems and biotechnology due to their diverse array of metabolic products. However, research on the biodiversity of soil Streptomyces across extensive geographical scales in China has been limited, and their genetic diversity has rarely been evaluated using modern population genetics principles. This pilot study successfully addresses these gaps by conducting a preliminary exploration on the biodiversity of Streptomyces in Chinese soils from multiple perspectives, providing valuable insights for a deeper understanding of their biodiversity and a novel technical framework for future large-scale explorations of its diversity.
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Affiliation(s)
- Ziguang Deng
- Key Laboratory of Evolution & Marine Biodiversity (Ministry of Education) and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, Shandong Province, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, Shandong Province, China
| | - Wei Yang
- Key Laboratory of Evolution & Marine Biodiversity (Ministry of Education) and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, Shandong Province, China
| | - Tongtong Lin
- Key Laboratory of Evolution & Marine Biodiversity (Ministry of Education) and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, Shandong Province, China
| | - Yaohai Wang
- Key Laboratory of Evolution & Marine Biodiversity (Ministry of Education) and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, Shandong Province, China
| | - Xiaojing Hua
- Key Laboratory of Evolution & Marine Biodiversity (Ministry of Education) and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, Shandong Province, China
| | - Xiaoyu Jiang
- Key Laboratory of Evolution & Marine Biodiversity (Ministry of Education) and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, Shandong Province, China
| | - Junhao Chen
- Key Laboratory of Evolution & Marine Biodiversity (Ministry of Education) and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, Shandong Province, China
| | - Dan Liu
- Key Laboratory of Evolution & Marine Biodiversity (Ministry of Education) and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, Shandong Province, China
| | - Zhiqiang Ye
- School of Life Sciences, Central China Normal University, Wuhan, Hubei Province, China
| | - Yu Zhang
- Key Laboratory of Evolution & Marine Biodiversity (Ministry of Education) and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, Shandong Province, China
| | - Michael Lynch
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, Arizona, USA
| | - Hongan Long
- Key Laboratory of Evolution & Marine Biodiversity (Ministry of Education) and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, Shandong Province, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, Shandong Province, China
| | - Jiao Pan
- Key Laboratory of Evolution & Marine Biodiversity (Ministry of Education) and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, Shandong Province, China
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Kopecky J, Kamenik Z, Omelka M, Novotna J, Stefani T, Sagova-Mareckova M. Phylogenetically related soil actinomycetes distinguish isolation sites by their metabolic activities. FEMS Microbiol Ecol 2023; 99:fiad139. [PMID: 37935470 DOI: 10.1093/femsec/fiad139] [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: 02/01/2023] [Revised: 08/24/2023] [Accepted: 11/02/2023] [Indexed: 11/09/2023] Open
Abstract
Soil environments are inhabited by microorganisms adapted to its diversified microhabitats. The metabolic activity of individual strains/populations reflects resources available at a particular spot, quality of which may not comply with broad soil characteristics. To explore the potential of individual strains to adapt to particular micro-niches of carbon sources, a set of 331 Actinomycetia strains were collected at ten sites differing in vegetation, soil pH, organic matter content and quality. The strains were isolated on the same complex medium with neutral pH and their metabolites analyzed by UHPLC and LC-MS/MS in spent cultivation medium (metabolic profiles). For all strains, their metabolic profiles correlated with soil pH and organic matter content of the original sites. In comparison, strains phylogeny based on either 16S rRNA or the beta-subunit of DNA-dependent RNA polymerase (rpoB) genes was partially correlated with soil organic matter content but not soil pH at the sites. Antimicrobial activities of strains against Kocuria rhizophila, Escherichia coli, and Saccharomyces cerevisiae were both site- and phylogeny-dependent. The precise adaptation of metabolic profiles to overall sites characteristics was further supported by the production of locally specific bioactive metabolites and suggested that carbon resources represent a significant selection pressure connected to specific antibiotic activities.
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Affiliation(s)
- Jan Kopecky
- Epidemiology and Ecology of Microorganisms, Crop Research Institute, 161 06 Prague, Czechia
| | - Zdenek Kamenik
- Laboratory for Biology of Secondary Metabolism, Institute of Microbiology, Czech Acad Sci, 142 20 Prague, Czechia
| | - Marek Omelka
- Department of Probability and Mathematical Statistics, Faculty of Mathematics and Physics, Charles University, 186 75 Prague, Czechia
| | - Jitka Novotna
- Epidemiology and Ecology of Microorganisms, Crop Research Institute, 161 06 Prague, Czechia
| | - Tommaso Stefani
- Laboratory for Biology of Secondary Metabolism, Institute of Microbiology, Czech Acad Sci, 142 20 Prague, Czechia
| | - Marketa Sagova-Mareckova
- Department of Microbiology, Nutrition and Dietetics, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences, 165 21 Prague, Czechia
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Kokate PP, Bales E, Joyner D, Hazen TC, Techtmann SM. Biogeographic patterns in populations of marine Pseudoalteromonas atlantica isolates. FEMS Microbiol Lett 2023; 370:fnad081. [PMID: 37573136 DOI: 10.1093/femsle/fnad081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 07/14/2023] [Accepted: 08/11/2023] [Indexed: 08/14/2023] Open
Abstract
Intra-specific genomic diversity is well documented in microbes. The question, however, remains whether natural selection or neutral evolution is the major contributor to this diversity. We undertook this study to estimate genomic diversity in Pseudoalteromonas atlantica populations and whether the diversity, if present, could be attributed to environmental factors or distance effects. We isolated and sequenced twenty-three strains of P. atlantica from three geographically distant deep marine basins and performed comparative genomic analyses to study the genomic diversity of populations among these basins. Average nucleotide identity followed a strictly geographical pattern. In two out of three locations, the strains within the location exhibited >99.5% identity, whereas, among locations, the strains showed <98.11% identity. Phylogenetic and pan-genome analysis also reflected the biogeographical separation of the strains. Strains from the same location shared many accessory genes and clustered closely on the phylogenetic tree. Phenotypic diversity between populations was studied in ten out of twenty-three strains testing carbon and nitrogen source utilization and osmotolerance. A genetic basis for phenotypic diversity could be established in most cases but was apparently not influenced by local environmental conditions. Our study suggests that neutral evolution may have a substantial role in the biodiversity of P. atlantica.
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Affiliation(s)
- Prajakta P Kokate
- Department of Biological Sciences, Michigan Technological University, Houghton, MI 49931, United States
| | - Erika Bales
- Department of Microbiology, University of Tennessee Knoxville, Knoxville, TN 37996, United States
| | - Dominique Joyner
- Department of Civil and Environmental Engineering, University of Tennessee Knoxville, Knoxville, TN 37996, United States
| | - Terry C Hazen
- Department of Microbiology, University of Tennessee Knoxville, Knoxville, TN 37996, United States
- Department of Civil and Environmental Engineering, University of Tennessee Knoxville, Knoxville, TN 37996, United States
| | - Stephen M Techtmann
- Department of Biological Sciences, Michigan Technological University, Houghton, MI 49931, United States
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Greenlon A, Sieradzki E, Zablocki O, Koch BJ, Foley MM, Kimbrel JA, Hungate BA, Blazewicz SJ, Nuccio EE, Sun CL, Chew A, Mancilla CJ, Sullivan MB, Firestone M, Pett-Ridge J, Banfield JF. Quantitative Stable-Isotope Probing (qSIP) with Metagenomics Links Microbial Physiology and Activity to Soil Moisture in Mediterranean-Climate Grassland Ecosystems. mSystems 2022; 7:e0041722. [PMID: 36300946 PMCID: PMC9765451 DOI: 10.1128/msystems.00417-22] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 10/02/2022] [Indexed: 12/25/2022] Open
Abstract
The growth and physiology of soil microorganisms, which play vital roles in biogeochemical cycling, are shaped by both current and historical soil environmental conditions. Here, we developed and applied a genome-resolved metagenomic implementation of quantitative stable isotope probing (qSIP) with an H218O labeling experiment to identify actively growing soil microorganisms and their genomic capacities. qSIP enabled measurement of taxon-specific growth because isotopic incorporation into microbial DNA requires production of new genome copies. We studied three Mediterranean grassland soils across a rainfall gradient to evaluate the hypothesis that historic precipitation levels are an important factor controlling trait selection. We used qSIP-informed genome-resolved metagenomics to resolve the active subset of soil community members and identify their characteristic ecophysiological traits. Higher year-round precipitation levels correlated with higher activity and growth rates of flagellar motile microorganisms. In addition to heavily isotopically labeled bacteria, we identified abundant isotope-labeled phages, suggesting phage-induced cell lysis likely contributed to necromass production at all three sites. Further, there was a positive correlation between phage activity and the activity of putative phage hosts. Contrary to our expectations, the capacity to decompose the diverse complex carbohydrates common in soil organic matter or oxidize methanol and carbon monoxide were broadly distributed across active and inactive bacteria in all three soils, implying that these traits are not highly selected for by historical precipitation. IMPORTANCE Soil moisture is a critical factor that strongly shapes the lifestyle of soil organisms by changing access to nutrients, controlling oxygen diffusion, and regulating the potential for mobility. We identified active microorganisms in three grassland soils with similar mineral contexts, yet different historic rainfall inputs, by adding water labeled with a stable isotope and tracking that isotope in DNA of growing microbes. By examining the genomes of active and inactive microorganisms, we identified functions that are enriched in growing organisms, and showed that different functions were selected for in different soils. Wetter soil had higher activity of motile organisms, but activity of pathways for degradation of soil organic carbon compounds, including simple carbon substrates, were comparable for all three soils. We identified many labeled, and thus active bacteriophages (viruses that infect bacteria), implying that the cells they killed contributed to soil organic matter. The activity of these bacteriophages was significantly correlated with activity of their hosts.
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Affiliation(s)
- Alex Greenlon
- Department of Environmental Science, Policy and Management, University California, Berkeley, Berkley, California, USA
| | - Ella Sieradzki
- Department of Environmental Science, Policy and Management, University California, Berkeley, Berkley, California, USA
| | - Olivier Zablocki
- Department of Microbiology, Ohio State University, Columbus, Ohio, USA
- Center of Microbiome Science, Ohio State University, Columbus, Ohio, USA
| | - Benjamin J. Koch
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Megan M. Foley
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Jeffrey A. Kimbrel
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, USA
| | - Bruce A. Hungate
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Steven J. Blazewicz
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, USA
| | - Erin E. Nuccio
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, USA
| | - Christine L. Sun
- Department of Microbiology, Ohio State University, Columbus, Ohio, USA
- Center of Microbiome Science, Ohio State University, Columbus, Ohio, USA
| | - Aaron Chew
- Department of Environmental Science, Policy and Management, University California, Berkeley, Berkley, California, USA
| | - Cynthia-Jeanette Mancilla
- Department of Environmental Science, Policy and Management, University California, Berkeley, Berkley, California, USA
| | - Matthew B. Sullivan
- Department of Microbiology, Ohio State University, Columbus, Ohio, USA
- Center of Microbiome Science, Ohio State University, Columbus, Ohio, USA
- Department of Civil, Environmental and Geodetic Engineering, Ohio State University, Columbus, Ohio, USA
| | - Mary Firestone
- Department of Environmental Science, Policy and Management, University California, Berkeley, Berkley, California, USA
| | - Jennifer Pett-Ridge
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, USA
- Life & Environmental Sciences Department, University of California, Merced, Merced, California, USA
| | - Jillian F. Banfield
- Department of Environmental Science, Policy and Management, University California, Berkeley, Berkley, California, USA
- Department of Earth and Planetary Science, University of California, Berkeley, Berkley, California, USA
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Coastal Transient Niches Shape the Microdiversity Pattern of a Bacterioplankton Population with Reduced Genomes. mBio 2022; 13:e0057122. [PMID: 35880883 PMCID: PMC9426536 DOI: 10.1128/mbio.00571-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Globally dominant marine bacterioplankton lineages are often limited in metabolic versatility, owing to their extensive genome reductions, and thus cannot take advantage of transient nutrient patches. It is therefore perplexing how the nutrient-poor bulk seawater sustains the pelagic streamlined lineages, each containing numerous populations. Here, we sequenced the genomes of 33 isolates of the recently discovered CHUG lineage (~2.6 Mbp), which have some of the smallest genomes in the globally abundant Roseobacter group (commonly over 4 Mbp). These genome-reduced bacteria were isolated from a transient habitat: seawater surrounding the brown alga, Sargassum hemiphyllum. Population genomic analyses showed that: (i) these isolates, despite sharing identical 16S rRNA genes, were differentiated into several genetically isolated populations through successive speciation events; (ii) only the first speciation event led to the genetic separation of both core and accessory genomes; and (iii) populations resulting from this event are differentiated at many loci involved in carbon utilization and oxygen respiration, corroborated by BiOLOG phenotype microarray assays and oxygen uptake kinetics experiments, respectively. These differentiated traits match well with the dynamic nature of the macroalgal seawater, in which the quantity and quality of carbon sources and the concentration of oxygen likely vary spatially and temporally, though other habitats, like fresh organic aggregates, cannot be ruled out. Our study implies that transient habitats in the overall nutrient-poor ocean can shape the microdiversity and population structure of genome-reduced bacterioplankton lineages.
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Hariharan J, Buckley DH. Elevational Gradients Impose Dispersal Limitation on Streptomyces. Front Microbiol 2022; 13:856263. [PMID: 35592003 PMCID: PMC9113539 DOI: 10.3389/fmicb.2022.856263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 03/25/2022] [Indexed: 11/16/2022] Open
Abstract
Dispersal governs microbial biogeography, but the rates and mechanisms of dispersal remain poorly characterized for most microbial taxa. Dispersal limitation is driven by limits on dissemination and establishment, respectively. Elevation gradients create striking patterns of biogeography because they produce steep environmental gradients at small spatial scales, and these gradients offer a powerful tool to examine mechanisms of dispersal limitation. We focus on Streptomyces, a bacterial genus common to soil, by using a taxon-specific phylogenetic marker, the RNA polymerase-encoding rpoB gene. By targeting Streptomyces, we assess dispersal limitation at finer phylogenetic resolution than is possible using whole community analyses. We characterized Streptomyces diversity at local spatial scales (100 to 3,000 m) in two temperate forest sites located in the Adirondacks region of New York State: Woods Lake (<100 m elevation change), and Whiteface Mountain (>1,000 m elevation change). Beta diversity varied considerably at both locations, indicative of dispersal limitation acting at local spatial scales, but beta diversity was significantly higher at Whiteface Mountain. Beta diversity varied across elevation at Whiteface Mountain, being lowest at the mountain’s base. We show that Streptomyces taxa exhibit elevational preferences, and these preferences are phylogenetically conserved. These results indicate that habitat preferences influence Streptomyces biogeography and suggest that barriers to establishment structure Streptomyces communities at higher elevations. These data illustrate that Streptomyces biogeography is governed by dispersal limitation resulting from a complex mixture of stochastic and deterministic processes.
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Affiliation(s)
- Janani Hariharan
- School of Integrative Plant Science, Cornell University, Ithaca, NY, United States
| | - Daniel H Buckley
- School of Integrative Plant Science, Cornell University, Ithaca, NY, United States
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7
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Habitat Adaptation Drives Speciation of a Streptomyces Species with Distinct Habitats and Disparate Geographic Origins. mBio 2022; 13:e0278121. [PMID: 35012331 PMCID: PMC8749437 DOI: 10.1128/mbio.02781-21] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Microbial diversification is driven by geographic and ecological factors, but how the relative importance of these factors varies among species, geographic scales, and habitats remains unclear. Streptomyces, a genus of antibiotic-producing, spore-forming, and widespread bacteria, offers a robust model for identifying the processes underlying population differentiation. We examined the population structure of 37 Streptomyces olivaceus strains isolated from various sources, showing that they diverged into two habitat-associated (free-living and insect-associated) and geographically disparate lineages. More frequent gene flow within than between the lineages confirmed genetic isolation in S. olivaceus. Geographic isolation could not explain the genetic isolation; instead, habitat type was a strong predictor of genetic distance when controlling for geographic distance. The identification of habitat-specific genetic variations, including genes involved in regulation, resource use, and secondary metabolism, suggested a significant role of habitat adaptation in the diversification process. Physiological assays revealed fitness trade-offs under different environmental conditions in the two lineages. Notably, insect-associated isolates could outcompete free-living isolates in a free-iron-deficient environment. Furthermore, substrate (e.g., sialic acid and glycogen) utilization but not thermal traits differentiated the two lineages. Overall, our results argue that adaptive processes drove ecological divergence among closely related streptomycetes, eventually leading to dispersal limitation and gene flow barriers between the lineages. S. olivaceus may best be considered a species complex consisting of two cryptic species. IMPORTANCE Both isolation by distance and isolation by environment occur in bacteria, and different diversification patterns may apply to different species. Streptomyces species, typified by producing useful natural products, are widespread in nature and possess high genetic diversity. However, the ecological processes and evolutionary mechanisms that shape their distribution are not well understood. Here, we show that the population structure of a ubiquitous Streptomyces species complex matches its habitat distribution and can be defined by gene flow discontinuities. Using comparative genomics and physiological assays, we reveal that gains and losses of specific genomic traits play a significant role in the transition between free-living and host-associated lifestyles, driving speciation of the species. These results provide new insights into the evolutionary trajectory of Streptomyces and the notion of species.
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Fernández LD, Seppey CVW, Singer D, Fournier B, Tatti D, Mitchell EAD, Lara E. Niche Conservatism Drives the Elevational Diversity Gradient in Major Groups of Free-Living Soil Unicellular Eukaryotes. MICROBIAL ECOLOGY 2022; 83:459-469. [PMID: 34052880 DOI: 10.1007/s00248-021-01771-2] [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: 12/07/2020] [Accepted: 05/10/2021] [Indexed: 06/12/2023]
Abstract
Ancestral adaptations to tropical-like climates drive most multicellular biogeography and macroecology. Observational studies suggest that this niche conservatism could also be shaping unicellular biogeography and macroecology, although evidence is limited to Acidobacteria and testate amoebae. We tracked the phylogenetic signal of this niche conservatism in far related and functionally contrasted groups of common soil protists (Bacillariophyta, Cercomonadida, Ciliophora, Euglyphida and Kinetoplastida) along a humid but increasingly cold elevational gradient in Switzerland. Protist diversity decreased, and the size of the geographic ranges of taxa increased with elevation and associated decreasing temperature (climate), which is consistent with a macroecological pattern known as the Rapoport effect. Bacillariophyta exhibited phylogenetically overdispersed communities assembled by competitive exclusion of closely related taxa with shared (conserved) niches. By contrast, Cercomonadida, Ciliophora, Euglyphida and Kinetoplastida exhibited phylogenetically clustered communities assembled by habitat filtering, revealing the coexistence of closely related taxa with shared (conserved) adaptations to cope with the humid but temperate to cold climate of the study site. Phylobetadiversity revealed that soil protists exhibit a strong phylogenetic turnover among elevational sites, suggesting that most taxa have evolutionary constraints that prevent them from colonizing the colder and higher sites of the elevation gradient. Our results suggest that evolutionary constraints determine how soil protists colonize climates departing from warm and humid conditions. We posit that these evolutionary constraints are linked to an ancestral adaptation to tropical-like climates, which limits their survival in exceedingly cold sites. This niche conservatism possibly drives their biogeography and macroecology along latitudinal and altitudinal climatic gradients.
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Affiliation(s)
- Leonardo D Fernández
- Centro de Investigación en Recursos Naturales y Sustentabilidad (CIRENYS), Universidad Bernardo O'Higgins, Avenida Viel 1497, Santiago, Chile.
- Laboratory of Soil Biodiversity, Institute of Biology, University of Neuchâtel, Rue Emile Argand 11, CH-2000, Neuchâtel, Switzerland.
| | - Christophe V W Seppey
- Laboratory of Soil Biodiversity, Institute of Biology, University of Neuchâtel, Rue Emile Argand 11, CH-2000, Neuchâtel, Switzerland
- Institute of Arctic and Marine Biology, UiT The Arctic University of Norway, Framstredet 39, 9019, Tromsø, Norway
- Institute of Environmental Sciences and Geography, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany
| | - David Singer
- Laboratory of Soil Biodiversity, Institute of Biology, University of Neuchâtel, Rue Emile Argand 11, CH-2000, Neuchâtel, Switzerland
- Department of Zoology, Institute of Biosciences, University of São Paulo, São Paulo, 05508-090, Brazil
- UMR CNRS 6112 LPG-BIAF, Université D'Angers, Cedex 1, Angers, France
| | - Bertrand Fournier
- Institute of Environmental Sciences and Geography, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany
| | - Dylan Tatti
- Division Agronomie, Soil Protection and Use Group, School of Agricultural, Forest and Food Sciences HAFL, Bern University of Applied Sciences BFH, Länggasse 85, 3052, Zollikofen, Switzerland
| | - Edward A D Mitchell
- Laboratory of Soil Biodiversity, Institute of Biology, University of Neuchâtel, Rue Emile Argand 11, CH-2000, Neuchâtel, Switzerland
- Botanical Garden of Neuchâtel, Chemin du Pertuis-du-Sault 58, CH-2000, Neuchâtel, Switzerland
| | - Enrique Lara
- Laboratory of Soil Biodiversity, Institute of Biology, University of Neuchâtel, Rue Emile Argand 11, CH-2000, Neuchâtel, Switzerland
- Department of Mycology, Real Jardín Botánico de Madrid, CSIC, Plaza de Murillo 2, 28014, Madrid, Spain
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Fodelianakis S, Washburne AD, Bourquin M, Pramateftaki P, Kohler TJ, Styllas M, Tolosano M, De Staercke V, Schön M, Busi SB, Brandani J, Wilmes P, Peter H, Battin TJ. Microdiversity characterizes prevalent phylogenetic clades in the glacier-fed stream microbiome. ISME JOURNAL 2021; 16:666-675. [PMID: 34522009 PMCID: PMC8857233 DOI: 10.1038/s41396-021-01106-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 08/14/2021] [Accepted: 09/02/2021] [Indexed: 02/01/2023]
Abstract
Glacier-fed streams (GFSs) are extreme and rapidly vanishing ecosystems, and yet they harbor diverse microbial communities. Although our understanding of the GFS microbiome has recently increased, we do not know which microbial clades are ecologically successful in these ecosystems, nor do we understand potentially underlying mechanisms. Ecologically successful clades should be more prevalent across GFSs compared to other clades, which should be reflected as clade-wise distinctly low phylogenetic turnover. However, methods to assess such patterns are currently missing. Here we developed and applied a novel analytical framework, “phyloscore analysis”, to identify clades with lower spatial phylogenetic turnover than other clades in the sediment microbiome across twenty GFSs in New Zealand. These clades constituted up to 44% and 64% of community α-diversity and abundance, respectively. Furthermore, both their α-diversity and abundance increased as sediment chlorophyll a decreased, corroborating their ecological success in GFS habitats largely devoid of primary production. These clades also contained elevated levels of putative microdiversity than others, which could potentially explain their high prevalence in GFSs. This hitherto unknown microdiversity may be threatened as glaciers shrink, urging towards further genomic and functional exploration of the GFS microbiome.
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Affiliation(s)
- Stilianos Fodelianakis
- Stream Biofilm & Ecosystem Research Lab, ENAC Division, Ecole Polytechnique Fédérale de Lausanne, EPFL, Lausanne, Switzerland.
| | | | - Massimo Bourquin
- Stream Biofilm & Ecosystem Research Lab, ENAC Division, Ecole Polytechnique Fédérale de Lausanne, EPFL, Lausanne, Switzerland
| | - Paraskevi Pramateftaki
- Stream Biofilm & Ecosystem Research Lab, ENAC Division, Ecole Polytechnique Fédérale de Lausanne, EPFL, Lausanne, Switzerland
| | - Tyler J Kohler
- Stream Biofilm & Ecosystem Research Lab, ENAC Division, Ecole Polytechnique Fédérale de Lausanne, EPFL, Lausanne, Switzerland
| | - Michail Styllas
- Stream Biofilm & Ecosystem Research Lab, ENAC Division, Ecole Polytechnique Fédérale de Lausanne, EPFL, Lausanne, Switzerland
| | - Matteo Tolosano
- Stream Biofilm & Ecosystem Research Lab, ENAC Division, Ecole Polytechnique Fédérale de Lausanne, EPFL, Lausanne, Switzerland
| | - Vincent De Staercke
- Stream Biofilm & Ecosystem Research Lab, ENAC Division, Ecole Polytechnique Fédérale de Lausanne, EPFL, Lausanne, Switzerland
| | - Martina Schön
- Stream Biofilm & Ecosystem Research Lab, ENAC Division, Ecole Polytechnique Fédérale de Lausanne, EPFL, Lausanne, Switzerland
| | - Susheel Bhanu Busi
- Systems Ecology Research Group, Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Jade Brandani
- Stream Biofilm & Ecosystem Research Lab, ENAC Division, Ecole Polytechnique Fédérale de Lausanne, EPFL, Lausanne, Switzerland
| | - Paul Wilmes
- Systems Ecology Research Group, Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Hannes Peter
- Stream Biofilm & Ecosystem Research Lab, ENAC Division, Ecole Polytechnique Fédérale de Lausanne, EPFL, Lausanne, Switzerland
| | - Tom J Battin
- Stream Biofilm & Ecosystem Research Lab, ENAC Division, Ecole Polytechnique Fédérale de Lausanne, EPFL, Lausanne, Switzerland.
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10
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Higgins SA, Panke-Buisse K, Buckley DH. The biogeography of Streptomyces in New Zealand enabled by high-throughput sequencing of genus-specific rpoB amplicons. Environ Microbiol 2020; 23:1452-1468. [PMID: 33283920 DOI: 10.1111/1462-2920.15350] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Accepted: 12/02/2020] [Indexed: 01/10/2023]
Abstract
We evaluated Streptomyces biogeography in soils along a 1200 km latitudinal transect across New Zealand (NZ). Streptomyces diversity was examined using high-throughput sequencing of rpoB amplicons generated with a Streptomyces specific primer set. We detected 1287 Streptomyces rpoB operational taxonomic units (OTUs) with 159 ± 92 (average ± SD) rpoB OTUs per site. Only 12% (n = 149) of these OTUs matched rpoB sequences from cultured specimens (99% nucleotide identity cutoff). Streptomyces phylogenetic diversity (Faith's PD) was correlated with soil pH, mean annual temperature and plant community richness (Spearman's r: 0.77, 0.64 and -0.79, respectively; P < 0.05), but not with latitude. In addition, soil pH and plant community richness both explained significant variation in Streptomyces beta diversity. Streptomyces communities exhibited both high dissimilarity and strong dominance of one or a few species at each site. Taken together, these results suggest that dispersal limitation due to competitive interactions limits the colonization success of spores that relocate to new sites. Cultivated Streptomyces isolates represent a major source of clinically useful antibiotics, but only a small fraction of extant diversity within the genus have been identified and most species of Streptomyces have yet to be described.
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Affiliation(s)
- S A Higgins
- School of Integrative Plant Science, Cornell University, Ithaca, New York, 14853, USA.,Boyce Thompson Institute, Ithaca, NY, USA
| | - K Panke-Buisse
- School of Integrative Plant Science, Cornell University, Ithaca, New York, 14853, USA.,USDA Agricultural Research Service, Madison, WI, USA
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11
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Fillinger L, Hug K, Griebler C. Selection imposed by local environmental conditions drives differences in microbial community composition across geographically distinct groundwater aquifers. FEMS Microbiol Ecol 2020; 95:5584335. [PMID: 31598689 PMCID: PMC6821248 DOI: 10.1093/femsec/fiz160] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 10/06/2019] [Indexed: 12/21/2022] Open
Abstract
Several studies have analyzed biogeographic distribution patterns of microbial communities across broad spatial scales. However, it is often unclear to what extent differences in community composition across different regions are caused by dispersal limitation or selection, and if selection is caused by local environmental conditions alone or additional broad-scale region-specific factors. This is especially true for groundwater environments, which have been understudied in this context relative to other non-subsurface habitats. Here, we analyzed microbial community composition based on exact 16S rRNA amplicon sequence variants (ASVs) from four geographically separated aquifers located in different regions along a latitudinal transect of ∼700 km across Germany. Using a combination of variation partitioning and ecological null models revealed that differences in microbial community composition were mainly the product of selection imposed by local environmental conditions and to a smaller but still significant extent dispersal limitation and drift across regions. Only ∼23% of the total variation in microbial community composition remained unexplained, possibly due to underestimated effects of dispersal limitation among local communities within regions and temporal drift. No evidence was found for selection due to region-specific factors independent of local environmental conditions.
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Affiliation(s)
- Lucas Fillinger
- Helmholtz Zentrum München, Institute of Groundwater Ecology, Ingolstädter Landstrasse 1, Neuherberg 85764, Germany
| | - Katrin Hug
- Helmholtz Zentrum München, Institute of Groundwater Ecology, Ingolstädter Landstrasse 1, Neuherberg 85764, Germany
| | - Christian Griebler
- Helmholtz Zentrum München, Institute of Groundwater Ecology, Ingolstädter Landstrasse 1, Neuherberg 85764, Germany.,Department of Limnology & Bio-Oceanography, Centre of Functional Ecology, University of Vienna, Althanstrasse 14, Vienna 1090, Austria
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12
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Abstract
Due to the promiscuous exchange of genetic material and asexual reproduction, delineating microbial species (and, by extension, populations) remains challenging. Because of this, the vast majority of microbial studies assessing population structure often compare divergent strains from disparate environments under varied selective pressures. Here, we investigated the population structure within a single bacterial ecotype, a unit equivalent to a eukaryotic species, defined as highly clustered genotypic and phenotypic strains with the same ecological niche. Using a combination of genomic and computational analyses, we assessed the phylogenetic structure, extent of recombination, and flexible gene content of this genomic diversity to infer patterns of gene flow. To our knowledge, this study is the first to do so for a dominant soil bacterium. Our results indicate that bacterial soil populations, similarly to those in other environments, are structured by gene flow discontinuities and exhibit distributional patterns consistent with both isolation by distance and isolation by environment. Thus, both dispersal limitation and local environments contribute to the divergence among closely related soil bacteria as observed in macroorganisms. For free-living bacteria and archaea, the equivalent of the biological species concept does not exist, creating several obstacles to the study of the processes contributing to microbial diversification. These obstacles are particularly high in soil, where high bacterial diversity inhibits the study of closely related genotypes and therefore the factors structuring microbial populations. Here, we isolated strains within a single Curtobacterium ecotype from surface soil (leaf litter) across a regional climate gradient and investigated the phylogenetic structure, recombination, and flexible gene content of this genomic diversity to infer patterns of gene flow. Our results indicate that microbial populations are delineated by gene flow discontinuities, with distinct populations cooccurring at multiple sites. Bacterial population structure was further delineated by genomic features allowing for the identification of candidate genes possibly contributing to local adaptation. These results suggest that the genetic structure within this bacterium is maintained both by ecological specialization in localized microenvironments (isolation by environment) and by dispersal limitation between geographic locations (isolation by distance).
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13
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Greenlon A, Chang PL, Damtew ZM, Muleta A, Carrasquilla-Garcia N, Kim D, Nguyen HP, Suryawanshi V, Krieg CP, Yadav SK, Patel JS, Mukherjee A, Udupa S, Benjelloun I, Thami-Alami I, Yasin M, Patil B, Singh S, Sarma BK, von Wettberg EJB, Kahraman A, Bukun B, Assefa F, Tesfaye K, Fikre A, Cook DR. Global-level population genomics reveals differential effects of geography and phylogeny on horizontal gene transfer in soil bacteria. Proc Natl Acad Sci U S A 2019; 116:15200-15209. [PMID: 31285337 PMCID: PMC6660780 DOI: 10.1073/pnas.1900056116] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Although microorganisms are known to dominate Earth's biospheres and drive biogeochemical cycling, little is known about the geographic distributions of microbial populations or the environmental factors that pattern those distributions. We used a global-level hierarchical sampling scheme to comprehensively characterize the evolutionary relationships and distributional limitations of the nitrogen-fixing bacterial symbionts of the crop chickpea, generating 1,027 draft whole-genome sequences at the level of bacterial populations, including 14 high-quality PacBio genomes from a phylogenetically representative subset. We find that diverse Mesorhizobium taxa perform symbiosis with chickpea and have largely overlapping global distributions. However, sampled locations cluster based on the phylogenetic diversity of Mesorhizobium populations, and diversity clusters correspond to edaphic and environmental factors, primarily soil type and latitude. Despite long-standing evolutionary divergence and geographic isolation, the diverse taxa observed to nodulate chickpea share a set of integrative conjugative elements (ICEs) that encode the major functions of the symbiosis. This symbiosis ICE takes 2 forms in the bacterial chromosome-tripartite and monopartite-with tripartite ICEs confined to a broadly distributed superspecies clade. The pairwise evolutionary relatedness of these elements is controlled as much by geographic distance as by the evolutionary relatedness of the background genome. In contrast, diversity in the broader gene content of Mesorhizobium genomes follows a tight linear relationship with core genome phylogenetic distance, with little detectable effect of geography. These results illustrate how geography and demography can operate differentially on the evolution of bacterial genomes and offer useful insights for the development of improved technologies for sustainable agriculture.
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Affiliation(s)
- Alex Greenlon
- Department of Plant Pathology, University of California, Davis, CA 95616
| | - Peter L Chang
- Department of Plant Pathology, University of California, Davis, CA 95616
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089
| | - Zehara Mohammed Damtew
- College of Natural Sciences, Addis Ababa University, Addis Ababa, 32853 Ethiopia
- Debre Zeit Agricultural Research Center, Ethiopian Institute for Agricultural Research, Bishoftu, Ethiopia
| | - Atsede Muleta
- College of Natural Sciences, Addis Ababa University, Addis Ababa, 32853 Ethiopia
| | | | - Donghyun Kim
- International Crop Research Institute for the Semi-Arid Tropics, Hyderabad 502324, India
| | - Hien P Nguyen
- United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, 183-8509 Tokyo, Japan
| | - Vasantika Suryawanshi
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089
| | - Christopher P Krieg
- Department of Biological Sciences, Florida International University, Miami, FL 33199
| | - Sudheer Kumar Yadav
- Department of Mycology and Plant Pathology, Banaras Hindu University, Varanasi 221005, India
| | - Jai Singh Patel
- Department of Mycology and Plant Pathology, Banaras Hindu University, Varanasi 221005, India
| | - Arpan Mukherjee
- Department of Mycology and Plant Pathology, Banaras Hindu University, Varanasi 221005, India
| | - Sripada Udupa
- Biodiversity and Integrated Gene Management Program, International Center for Agricultural Research in the Dry Areas, 10112 Rabat, Morocco
| | - Imane Benjelloun
- Institute National de la Recherche Agronomique, 10100 Rabat, Morocco
| | - Imane Thami-Alami
- Institute National de la Recherche Agronomique, 10100 Rabat, Morocco
| | | | - Bhuvaneshwara Patil
- Department of Genetics and Plant Breeding, University of Agricultural Sciences, Dharwad 580001, India
| | - Sarvjeet Singh
- Department of Plant Breeding and Genetics, Punjab Agricultural University, Ludhiana 141027, India
| | - Birinchi Kumar Sarma
- Department of Mycology and Plant Pathology, Banaras Hindu University, Varanasi 221005, India
| | - Eric J B von Wettberg
- Department of Biological Sciences, Florida International University, Miami, FL 33199
- Department of Plant and Soil Science, University of Vermont, Burlington, VT 05405
| | - Abdullah Kahraman
- Department of Field Crops, Faculty of Agriculture, Harran University, 63100 Sanliurfa, Turkey
| | - Bekir Bukun
- Department of Plant Protection, Dicle University, 21280 Diyarbakir, Turkey
| | - Fassil Assefa
- College of Natural Sciences, Addis Ababa University, Addis Ababa, 32853 Ethiopia
| | - Kassahun Tesfaye
- College of Natural Sciences, Addis Ababa University, Addis Ababa, 32853 Ethiopia
| | - Asnake Fikre
- Debre Zeit Agricultural Research Center, Ethiopian Institute for Agricultural Research, Bishoftu, Ethiopia
| | - Douglas R Cook
- Department of Plant Pathology, University of California, Davis, CA 95616;
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14
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Shen L, Liu Y, Wang N, Adhikari NP. Genomic Insights of Dyadobacter tibetensis Y620-1 Isolated from Ice Core Reveal Genomic Features for Succession in Glacier Environment. Microorganisms 2019; 7:E211. [PMID: 31336655 PMCID: PMC6680632 DOI: 10.3390/microorganisms7070211] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 07/04/2019] [Accepted: 07/18/2019] [Indexed: 12/26/2022] Open
Abstract
Glaciers have been recognized as biomes, dominated by microbial life. Many novel species have been isolated from glacier ecosystems, and their physiological features are well characterized. However, genomic features of bacteria isolated from the deep ice core are poorly understood. In this study, we performed a comparative genomic analysis to uncover the genomic features of strain Dyadobacter tibetensis Y620-1 isolated from a 59 m depth of the ice core drilled from a Tibetan Plateau glacier. Strain D. tibetensis Y620-1 had the smallest genome among the 12 cultured Dyadobacter strains, relatively low GC content, and was placed at the root position of the phylogenomic tree. The gene family based on a nonmetric multidimensional scaling (NMDS) plot revealed a clear separation of strain D. tibetensis Y620-1 from the reference strains. The genome of the deep ice core isolated strain contained the highest percentage of new genes. The definitive difference is that all genes required for the serine-glyoxylate cycle in one-carbon metabolism were only found in strain D. tibetensis Y620-1, but not in any of the reference strains. The placement of strain D. tibetensis Y620-1 in the root of the phylogenomic tree suggests that these new genes and functions are of ancient origin. All of these genomic features may contribute to the survival of D. tibetensis Y620-1 in the glacier.
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Affiliation(s)
- Liang Shen
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China
- CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100085, China
- College of Life Sciences, Anhui Normal University, Wuhu 241000, China
| | - Yongqin Liu
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China.
- CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100085, China.
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, China.
| | - Ninglian Wang
- CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100085, China
- College of Urban and Environmental Science, Northwest University, Xian 710069, China
| | - Namita Paudel Adhikari
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, China
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15
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Chase AB, Gomez-Lunar Z, Lopez AE, Li J, Allison SD, Martiny AC, Martiny JBH. Emergence of soil bacterial ecotypes along a climate gradient. Environ Microbiol 2018; 20:4112-4126. [PMID: 30209883 DOI: 10.1111/1462-2920.14405] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 08/03/2018] [Accepted: 09/06/2018] [Indexed: 11/28/2022]
Abstract
The high diversity of soil bacteria is attributed to the spatial complexity of soil systems, where habitat heterogeneity promotes niche partitioning among bacterial taxa. This premise remains challenging to test, however, as it requires quantifying the traits of closely related soil bacteria and relating these traits to bacterial abundances and geographic distributions. Here, we sought to investigate whether the widespread soil taxon Curtobacterium consists of multiple coexisting ecotypes with differential geographic distributions. We isolated Curtobacterium strains from six sites along a climate gradient and assayed four functional traits that may contribute to niche partitioning in leaf litter, the top layer of soil. Our results revealed that cultured isolates separated into fine-scale genetic clusters that reflected distinct suites of phenotypic traits, denoting the existence of multiple ecotypes. We then quantified the distribution of Curtobacterium by analysing metagenomic data collected across the gradient over 18 months. Six abundant ecotypes were observed with differential abundances along the gradient, suggesting fine-scale niche partitioning. However, we could not clearly explain observed geographic distributions of ecotypes by relating their traits to environmental variables. Thus, while we can resolve soil bacterial ecotypes, the traits delineating their distinct niches in the environment remain unclear.
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Affiliation(s)
- Alexander B Chase
- Department of Ecology and Evolutionary Biology, University of California, Irvine, California, USA
| | - Zulema Gomez-Lunar
- Department of Earth System Sciences, University of California, Irvine, California, USA
| | - Alberto E Lopez
- Department of Ecology and Evolutionary Biology, University of California, Irvine, California, USA
| | - Junhui Li
- Department of Earth System Sciences, University of California, Irvine, California, USA
| | - Steven D Allison
- Department of Ecology and Evolutionary Biology, University of California, Irvine, California, USA.,Department of Earth System Sciences, University of California, Irvine, California, USA
| | - Adam C Martiny
- Department of Ecology and Evolutionary Biology, University of California, Irvine, California, USA.,Department of Earth System Sciences, University of California, Irvine, California, USA
| | - Jennifer B H Martiny
- Department of Ecology and Evolutionary Biology, University of California, Irvine, California, USA
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16
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Choudoir MJ, Pepe-Ranney C, Buckley DH. Diversification of Secondary Metabolite Biosynthetic Gene Clusters Coincides with Lineage Divergence in Streptomyces. Antibiotics (Basel) 2018; 7:E12. [PMID: 29438308 PMCID: PMC5872123 DOI: 10.3390/antibiotics7010012] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 02/06/2018] [Accepted: 02/07/2018] [Indexed: 11/16/2022] Open
Abstract
We have identified Streptomyces sister-taxa which share a recent common ancestor and nearly identical small subunit (SSU) rRNA gene sequences, but inhabit distinct geographic ranges demarcated by latitude and have sufficient genomic divergence to represent distinct species. Here, we explore the evolutionary dynamics of secondary metabolite biosynthetic gene clusters (SMGCs) following lineage divergence of these sister-taxa. These sister-taxa strains contained 310 distinct SMGCs belonging to 22 different gene cluster classes. While there was broad conservation of these 22 gene cluster classes among the genomes analyzed, each individual genome harbored a different number of gene clusters within each class. A total of nine SMGCs were conserved across nearly all strains, but the majority (57%) of SMGCs were strain-specific. We show that while each individual genome has a unique combination of SMGCs, this diversity displays lineage-level modularity. Overall, the northern-derived (NDR) clade had more SMGCs than the southern-derived (SDR) clade (40.7 ± 3.9 and 33.8 ± 3.9, mean and S.D., respectively). This difference in SMGC content corresponded with differences in the number of predicted open reading frames (ORFs) per genome (7775 ± 196 and 7093 ± 205, mean and S.D., respectively) such that the ratio of SMGC:ORF did not differ between sister-taxa genomes. We show that changes in SMGC diversity between the sister-taxa were driven primarily by gene acquisition and deletion events, and these changes were associated with an overall change in genome size which accompanied lineage divergence.
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Affiliation(s)
- Mallory J Choudoir
- School of Integrative Plant Science, Bradfield Hall 705, Cornell University, Ithaca, NY 14853, USA.
| | - Charles Pepe-Ranney
- School of Integrative Plant Science, Bradfield Hall 705, Cornell University, Ithaca, NY 14853, USA.
| | - Daniel H Buckley
- School of Integrative Plant Science, Bradfield Hall 705, Cornell University, Ithaca, NY 14853, USA.
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