Neutral Evolution and Dispersal Limitation Produce Biogeographic Patterns in Microcystis aeruginosa Populations of Lake Systems

Shirani, Sahar; Hellweger, Ferdi L.

doi:10.1007/s00248-017-0963-5

Cited by 9 publications

(9 citation statements)

References 40 publications

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“…when the number of individuals in populations becomes relatively low (Crow & Kimura ), were extremely unlikely, because 3 × 10 5 cells were transferred in each step of the experiment, enough to avoid this. However, in scenarios with numerous small water bodies suffering salinization, neutral evolution and genetic drift events may occur, as has been recently described (Shirani & Hellweger ).…”

Section: Discussionmentioning

confidence: 87%

Adaptation of the toxic freshwater cyanobacterium Microcystis aeruginosa to salinity is achieved by the selection of spontaneous mutants

Melero‐Jiménez

Martín‐Clemente

García‐Sánchez

et al. 2019

Phycological Research

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SUMMARY The cyanobacterium Microcystis aeruginosa causes most of the harmful toxic blooms in freshwater ecosystems. Some strains of M. aeruginosa tolerate low‐medium levels of salinity, and because salinization of freshwater aquatic systems is increasing worldwide it is relevant to know what adaptive mechanisms allow tolerance to salinity. The mechanisms involved in the adaptation of M. aeruginosa to salinity (acclimation vs. genetic adaptation) were tested by a fluctuation analysis design, and then the maximum capacity of adaptation to salinity was studied by a ratchet protocol experiment. Whereas a dose of 10 g NaCl L−1 completely inhibited the growth of M. aeruginosa, salinity‐resistant genetic variants, capable of tolerating up to 14 g NaCl L−1, were isolated in the fluctuation analysis experiment. The salinity‐resistant cells arose by spontaneous mutations at a rate of 7.3 × 10−7 mutants per cell division. We observed with the ratchet protocol that three independent culture populations of M. aeruginosa were able to adapt to up to 15.1 g L−1 of NaCl, suggesting that successive mutation‐selection processes can enhance the highest salinity level to which M. aeruginosa cells can initially adapt. We propose that increasing salinity in water reservoirs could lead to the selection of salinity‐resistant mutants of M. aeruginosa.

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Section: Discussionmentioning

confidence: 87%

Adaptation of the toxic freshwater cyanobacterium Microcystis aeruginosa to salinity is achieved by the selection of spontaneous mutants

Melero‐Jiménez

Martín‐Clemente

García‐Sánchez

et al. 2019

Phycological Research

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“…Given sufficient assumptions (e.g., uniform mutation rates, no recombination, constant and independent fitness effect of mutations) simple theories or equations can be developed and applied (e.g., to predict codon usage bias) [19]. For more complex scenarios, including multiple mechanisms and many sites (i.e., base pairs or genes), an alternative approach is to directly simulate a population of individual cells with whole genomes [20][21][22]. In this individual-or agent-based approach, single cells are simulated explicitly and the population-level properties (e.g., diversity and population size) emerge from the cumulative properties and behaviors of these low-level entities [23].…”

Section: Introductionmentioning

confidence: 99%

Carbon limitation drives GC content evolution of a marine bacterium in an individual-based genome-scale model

2018

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An important unanswered question in evolutionary genomics is the source of considerable variation of genomic base composition (GC content) even among organisms that share one habitat. Evolution toward GC-poor genomes has been considered a major adaptive pathway in the oligotrophic ocean, but GC-rich bacteria are also prevalent and highly successful in this environment. We quantify the contribution of multiple factors to the change of genomic GC content of Ruegeria pomeroyi DSS-3, a representative and GC-rich member in the globally abundant Roseobacter clade, using an agent-based model. The model simulates 2 × 10 cells, which allows random genetic drift to act in a realistic manner. Each cell has a whole genome subject to base-substitution mutation and recombination, which affect the carbon and nitrogen requirements of DNA and protein pools. Nonsynonymous changes can be functionally deleterious. Together, these factors affect the growth and fitness. Simulations show that experimentally determined mutation bias toward GC is not sufficient to build the GC-rich genome of DSS-3. While nitrogen availability has been repeatedly hypothesized to drive the evolution of GC content in marine bacterioplankton, our model instead predicts that DSS-3 and its ancestors have been evolving in environments primarily limited by carbon.

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“…As dispersal limitation caused by geographic distance is one of the major mechanisms that maintain β-diversity of microbial communities (Eisenlord, Zak & Upchurch, 2012;Ni et al, 2014;Cao et al, 2016;Shirani & Hellweger, 2017), we analyzed the variation of the weighted UniFrac distances between the sampling sites with the geographic distances. Our results showed that the weighted UniFrac distances significantly increased with the increases of the geographic distances (Fig.…”

Section: Comparing the Rms Among Different Lakes Seasons And Sitesmentioning

confidence: 99%

Hydrological and soil physiochemical variables determine the rhizospheric microbiota in subtropical lakeshore areas

Zhang

Wang

et al. 2020

PeerJ

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Background Due to intensive sluice construction and other human disturbances, lakeshore vegetation has been destroyed and ecosystems greatly changed. Rhizospheric microbiota constitute a key part of a functioning rhizosphere ecosystem. Maintaining rhizosphere microbial diversity is a central, critical issue for sustaining these rhizospheric microbiota functions and associated ecosystem services. However, the community composition and abiotic factors influencing rhizospheric microbiota in lakeshore remain largely understudied. Methods The spatiotemporal composition of lakeshore rhizospheric microbiota and the factors shaping them were seasonally investigated in three subtropical floodplain lakes (Lake Chaohu, Lake Wuchang, and Lake Dahuchi) along the Yangtze River in China through 16S rRNA amplicon high-throughput sequencing. Results Our results showed that four archaeal and 21 bacterial phyla (97.04 ± 0.25% of total sequences) dominated the rhizospheric microbiota communities of three lakeshore areas. Moreover, we uncovered significant differences among rhizospheric microbiota among the lakes, seasons, and average submerged depths. The Acidobacteria, Actinobacteria, Bacteroidetes, Bathyarchaeota, Gemmatimonadetes, and Proteobacteria differed significantly among the three lakes, with more than half of these dominant phyla showing significant changes in abundance between seasons, while the DHVEG-6, Ignavibacteriae, Nitrospirae, Spirochaetes, and Zixibacteria varied considerably across the average submerged depths (n = 58 sites in total). Canonical correspondence analyses revealed that the fluctuation range of water level and pH were the most important factors influencing the microbial communities and their dominant microbiota, followed by total nitrogen, moisture, and total phosphorus in soil. These results suggest a suite of hydrological and soil physiochemical variables together governed the differential structuring of rhizospheric microbiota composition among different lakes, seasons, and sampling sites. This work thus provides valuable ecological information to better manage rhizospheric microbiota and protect the vegetation of subtropical lakeshore areas.

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Neutral Evolution and Dispersal Limitation Produce Biogeographic Patterns in Microcystis aeruginosa Populations of Lake Systems

Cited by 9 publications

References 40 publications

Adaptation of the toxic freshwater cyanobacterium Microcystis aeruginosa to salinity is achieved by the selection of spontaneous mutants

Adaptation of the toxic freshwater cyanobacterium Microcystis aeruginosa to salinity is achieved by the selection of spontaneous mutants

Carbon limitation drives GC content evolution of a marine bacterium in an individual-based genome-scale model

Hydrological and soil physiochemical variables determine the rhizospheric microbiota in subtropical lakeshore areas

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