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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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Duan Z, Tan X, Parajuli K, Zhang D, Wang Y. Characterization of Microcystis morphotypes: Implications for colony formation and intraspecific variation. HARMFUL ALGAE 2019; 90:101701. [PMID: 31806163 DOI: 10.1016/j.hal.2019.101701] [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: 05/28/2019] [Revised: 10/20/2019] [Accepted: 10/25/2019] [Indexed: 06/10/2023]
Abstract
Groundworks on Microcystis colony formation and morphological variation are critical to understanding the whole eco-cycle of Microcystis blooms. In this study, we tested the cell adhesion effect, an important pathway for colony formation, among Microcystis colonies of different morphotypes, and examined the potential linkage between cell properties and morphological plasticity. Results showed that cell adhesion significantly contributed to the aggregation of Microcystis colonies, but such adhesion only occurred in colonies belonging to the same morphotype. This suggests that Microcystis cannot form large colonies through a direct adhesion effect among different morphotypes, possibly due to substantial differences in the chemical structures and compositions of their extracellular polymeric substances (EPS). Cell functional features also varied substantially with morphotypes, implying high intraspecific variation in competitive and defensive strategies of Microcystis. Our results offer new insights into colony formation of Microcystis and substantiate the importance of fundamental chemical characteristics of EPS in determining the morphological plasticity.
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Affiliation(s)
- Zhipeng Duan
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China; Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708 PB Wageningen, Netherlands.
| | - Xiao Tan
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China.
| | - Keshab Parajuli
- School of Population and Global Health, Faculty of Medicine, Denistry and Health Sciences, The University of Melbourne, VIC 3010, Australia
| | - Danfeng Zhang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Yi Wang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
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Pérez-Carrascal OM, Terrat Y, Giani A, Fortin N, Greer CW, Tromas N, Shapiro BJ. Coherence of Microcystis species revealed through population genomics. ISME JOURNAL 2019; 13:2887-2900. [PMID: 31363173 DOI: 10.1038/s41396-019-0481-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 06/05/2019] [Accepted: 07/05/2019] [Indexed: 11/09/2022]
Abstract
Microcystis is a genus of freshwater cyanobacteria, which causes harmful blooms in ecosystems worldwide. Some Microcystis strains produce harmful toxins such as microcystin, impacting drinking water quality. Microcystis colony morphology, rather than genetic similarity, is often used to classify Microcystis into morphospecies. Yet colony morphology is a plastic trait, which can change depending on environmental and laboratory culture conditions, and is thus an inadequate criterion for species delineation. Furthermore, Microcystis populations are thought to disperse globally and constitute a homogeneous gene pool. However, this assertion is based on relatively incomplete characterization of Microcystis genomic diversity. To better understand these issues, we performed a population genomic analysis of 33 newly sequenced genomes mainly from Canada and Brazil. We identified 17 Microcystis clusters of genomic similarity, five of which correspond to monophyletic clades containing at least three newly sequenced genomes. Four out of these five clades match to named morphospecies. Notably, M. aeruginosa is paraphyletic, distributed across 12 genomic clusters, suggesting it is not a coherent species. A few clades of closely related isolates are specific to a unique geographic location, suggesting biogeographic structure over relatively short evolutionary time scales. Higher homologous recombination rates within than between clades further suggest that monophyletic groups might adhere to a Biological Species-like concept, in which barriers to gene flow maintain species distinctness. However, certain genes-including some involved in microcystin and micropeptin biosynthesis-are recombined between monophyletic groups in the same geographic location, suggesting local adaptation.
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Affiliation(s)
| | - Yves Terrat
- Département de Sciences Biologiques, Université de Montréal, Montréal, QC, Canada
| | - Alessandra Giani
- Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | | | | | - Nicolas Tromas
- Département de Sciences Biologiques, Université de Montréal, Montréal, QC, Canada.
| | - B Jesse Shapiro
- Département de Sciences Biologiques, Université de Montréal, Montréal, QC, Canada
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Li M, Xiao M, Zhang P, Hamilton DP. Morphospecies-dependent disaggregation of colonies of the cyanobacterium Microcystis under high turbulent mixing. WATER RESEARCH 2018; 141:340-348. [PMID: 29804020 DOI: 10.1016/j.watres.2018.05.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 05/08/2018] [Accepted: 05/10/2018] [Indexed: 06/08/2023]
Abstract
Preventing formation of large colonies and reducing colony size of the cyanobacterium Microcystis may lead to reductions in bloom formation. Here we investigated the effects of artificial mixing on morphology and disaggregation dynamics of Microcystis colonies in vivo, using a stirring device and a laser particle analyzer. The turbulent dissipation rate (ε) was varied from 0.020 to 0.364 m2 s-3. We hypothesized that colonies of M. aeruginosa and M. ichthyoblabe would be more susceptible to disaggregation from turbulent mixing than colonies of M. wesenbergii. Our results showed that colony size of M. aeruginosa and M. ichthyoblabe decreased with increased turbulence intensity and duration of stirring for ε > 0.094 m2 s-3, while M. wesenbergii showed less obvious changes in colony size with mixing. Spherical M. wesenbergii colonies exposed to high turbulence intensities for 30 min gradually transitioned to colony morphologies similar to M. ichthyoblabe and M. aeruginosa-like colonies (irregular, elongated or lobed, with distinct holes). Our results suggest that turbulent mixing is an important factor driving morphological changes of Microcystis colonies, and artificial mixing may effectively reduce colony size of Microcystis, thereby preventing bloom formation.
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Affiliation(s)
- Ming Li
- College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, PR China; Collaborative Innovation Center of Water Security for Water Source Region of Mid-line of South-to-North Diversion Project, Nanyang Normal University, Nanyang, 473061, PR China.
| | - Man Xiao
- Australian Rivers Institute, Griffith University, Nathan, QLD 4111, Australia; School of Environment, Griffith University, Nathan, QLD 4111, Australia
| | - Pei Zhang
- State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing, 210098, PR China; School of Civil Engineering, University of Queensland, St Lucia, QLD 4072, Australia
| | - David P Hamilton
- Australian Rivers Institute, Griffith University, Nathan, QLD 4111, Australia
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Duan Z, Tan X, Parajuli K, Upadhyay S, Zhang D, Shu X, Liu Q. Colony formation in two Microcystis morphotypes: Effects of temperature and nutrient availability. HARMFUL ALGAE 2018; 72:14-24. [PMID: 29413381 DOI: 10.1016/j.hal.2017.12.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 12/13/2017] [Accepted: 12/13/2017] [Indexed: 06/08/2023]
Abstract
The ability of Microcystis to form large colonies is a key trait that contributes to competition ability over other phytoplankton and facilitates the formation of surface scums in many freshwater systems. The effect of temperature and nutrients on this trait, however, is far from clear and needs further investigation, especially under a warmer climate and nutrient overloading in aquatic systems globally. In this study, two colonial strains of Microcystis (M. wesenbergii and M. ichthyoblabe) originally isolated from Lake Taihu in China, were used to investigate cyanobacterial aggregation under a range of temperatures (15-30 °C), phosphorus availability (0.004-8 mg P L-1), and nitrogen availability (0.04-40 mg N L-1). The mechanism of colony formation in Microcystis was determined based on growth rates and extracellular polysaccharide (EPS) contents. The colony size of both strains increased significantly when the temperature rose from 15 to 25 °C. A further increase in temperature from 25 to 30 °C, however, reduced the colony size of M. ichthyoblabe significantly, and, in contrast, increased the colony size of M. wesenbergii. Higher phosphorus availability promoted the formation of larger colonies in both strains. In comparison, nitrogen had no significant effect on the colony size. Furthermore, although EPS was a significant contributor to the formation of large colonies in colonial Microcystis, growth rate was a dominant driving factor in this process. The findings of this study highlight that warmer temperatures and phosphorus enrichment might enhance surface Microcystis scums directly through increasing the colony size. This study also provides new insights into the mechanism of colony formation in Microcystis.
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Affiliation(s)
- Zhipeng Duan
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Xiao Tan
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China.
| | | | - Sanjina Upadhyay
- Water Research Centre, School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Danfeng Zhang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Xiaoqian Shu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Qianqian Liu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
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