Allele-specific PCR shows that genetic exchange occurs among genetically diverse Nodularia (Cyanobacteria) filaments in the Baltic Sea

Barker, G. L.; Handley, B.A.; Vacharapiyasophon, Panmuk; Stevens, Jamie R.; Hayes, Paul K.

doi:10.1099/00221287-146-11-2865

Cited by 56 publications

(69 citation statements)

References 32 publications

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“…The STRR fingerprints of N. spumigena showed that the Baltic Sea population is not clonal. The result is in agreement with previous studies on noncoding regions, such as the 16S-23S rRNA ITS, gvpA-IGS and phycocyanin operon intergenic spacer (PC-IGS) (Barker et al, 1999(Barker et al, , 2000Laamanen et al, 2001). These studies revealed variation among Baltic N. spumigena strains sharing identical 16S rRNA genes.…”

Section: Phylogenetic Relationships Within the Genus Nodulariasupporting

confidence: 82%

Benthic cyanobacteria of the genus Nodularia are non-toxic, without gas vacuoles, able to glide and genetically more diverse than planktonic Nodularia

Lyra

Laamanen²,

Lehtimäki

et al. 2005

International Journal of Systematic and Evolutionary Microbiology

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Diversity and ecological features of cyanobacteria of the genus Nodularia from benthic, periphytic and soil habitats are less well known than those of Nodularia from planktonic habitats. Novel benthic Nodularia strains were isolated from the Baltic Sea and their morphology, the presence of gas vacuoles, nodularin production, gliding, 16S rRNA gene sequences, rpoB, rbcLX and ndaF genes, and gvpA-IGS regions were examined, as well as short tandemly repeated repetitive sequence fingerprints. Strains were identified as Nodularia spumigena, Nodularia sphaerocarpa or Nodularia harveyana on the basis of the size and shape of the different types of cells and the presence or absence of gas vacuoles. The planktonic strains of N. spumigena mostly had gas vacuoles and produced nodularin, whereas the benthic strains of N. sphaerocarpa and N. harveyana lacked gas vacuoles and did not produce nodularin (except for strain PCC 7804). The benthic strains were also able to glide on surfaces. In the genetic analyses, the planktonic N. spumigena and benthic N. sphaerocarpa formed monophyletic clusters, but the clusters were very closely related. Benthic strains determined as N. harveyana formed the most diverse and distant group of strains. In addition to phylogenetic analyses, the lack of the gvpA-IGS region and ndaF in N. sphaerocarpa and N. harveyana distinguished these species from the planktonic N. spumigena. Therefore, ndaF can be considered as a potential diagnostic tool for detecting and quantifying Baltic Sea bloom-forming, nodularin-producing N. spumigena strains. The data confirm that only one morphologically and genetically distinct planktonic species of Nodularia, N. spumigena, and at least two benthic species, N. sphaerocarpa and N. harveyana, exist in the Baltic Sea.

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Section: Phylogenetic Relationships Within the Genus Nodulariasupporting

confidence: 82%

Benthic cyanobacteria of the genus Nodularia are non-toxic, without gas vacuoles, able to glide and genetically more diverse than planktonic Nodularia

Lyra

Laamanen²,

Lehtimäki

et al. 2005

International Journal of Systematic and Evolutionary Microbiology

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“…The taxonomic assessment of Type 1 was another problem, although it resembled Nodularia baltica in heterocyst morphology, the latter being transversely oval to almost spherical and wider than vegetative cells. Further observations indicated that the tightly coiled filaments assigned to Type 1 could be statistically distinguished from Type 2 using our discriminant function .Our aim was, therefore, to show an application of the image analysis-based method we developed in order to estimate filamentous cyanobacterial biomass in mixed-species natural assemblages.Population genetic analysis of Nodularia partially carried out over the same area and period revealed that 3 out of the 12 allele-combinations distributed across the Baltic Sea were much more frequent than others (Barker et al 2000a). These data suggest a correlation between the 3 genotypes and the 3 morphotypes observed by us.…”

supporting

confidence: 60%

Morphometric variability of the genus Nodularia (Cyanobacteria) in Baltic natural communities

Congestri

Capucci²,

Albertano³

2003

Aquat. Microb. Ecol.

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Morphometric variability of the filamentous diazotroph Nodularia was determined in natural, mixed-species samples during a summer cyanobacterial bloom in the Central Baltic Sea using epifluorescence microscopy coupled with image analysis. A total of 1350 cyanobacterial filament images were acquired and a number of morphometric parameters measured for individual trichomes present in the samples and used to distinguish Nodularia from Aphanizomenon and Anabaena. The approach allowed automatic estimates of linear dimensions of Nodularia, Aphanizomenon and Anabaena, enabling us to evaluate their biovolume and vertical distribution, and to observe a high degree of morphometric variability in Nodularia filaments. We statistically analyzed this phenotypic diversity using previously collected datasets and adding further measurements. The data obtained were used to assess the variability in Nodularia trichome width and morphology and to establish the possible existence of 3 Nodularia 'morphotypes' by discriminant analysis. KEY WORDS: Nodularia · Morphometry · Image analysis · Discriminant analysis · Baltic Sea Resale or republication not permitted without written consent of the publisherAquat Microb Ecol 32: [251][252][253][254][255][256][257][258][259] 2003 brackish environments of the world (Sellner 1997, Bolch et al. 1999, Moisander & Pearl 2000, arousing public concern over their potential toxicity. In recent years, long-term data showed increasing trends in bloom quantity and intensity in the Baltic Basin (Finni et al. 2001).In this study we further tested the method based on epifluorescence microscopy combined with image analysis, as described by Congestri et al. (2000). The approach allowed automatic estimates of linear dimensions of all the heterocystous cyanobacterial genera present in the samples collected during summer 1999 in the Central Baltic Sea. Morphometric datasets of our previous work for each cyanobacterial genus are statistically analyzed in the present paper. Here we focus on Nodularia morphometry. This genus shows the largest variability, leading us to hypothesize a distinction between cell diameter classes within the natural assemblage. This hypothesis was statistically analyzed by discriminant analysis based on an extra dataset collected on Nodularia heterocyst morphometry. The presence of at least 2 distinct and more frequent morphotypes was statistically evidenced. This distinction seemed consistent with the traditional taxonomic assessment of Baltic Nodularia that discriminates between different species on the basis of the morphologic traits of the filaments (Komárek et al. 1993), but is in conflict with recent molecular data that indicate the existence of one species only (Barker et al. 2000a). In any case, our approach allowed automated or semi-automated analysis of the cyanobacterial community structure, thus contributing to a morphologic and morphometric characterization of taxa in natural assemblages, avoiding the loss of diacritical morphologic features and genotypic selectio...

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“…Recombination has also been observed in populations of Nodularia from the Baltic Sea (Barker et al, 2000). It has been suggested that the observation of genealogical concordance among groups but not within may provide an operational proxy for the application of the biological species concept (Dykhuizen & Green, 1991;Dettman et al, 2003).…”

Section: Discussionmentioning

confidence: 87%

Assessing host specialization in symbiotic cyanobacteria associated with four closely related species of the lichen fungusPeltigera

O’Brien

Miądlikowska

Lutzoni

2005

European Journal of Phycology

113

116

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Heterocystous cyanobacteria form symbiotic associations with a wide range of plant and fungal hosts. We used a molecular phylogenetic approach to investigate the degree of host specialization of cyanobacteria associated with four closely related species of the lichenized fungus Peltigera, and to compare these strains with other symbiotic cyanobacteria. We conducted phylogenetic analyses on 16S, rbcLX, and trnL sequences from cyanobacteria associated with multiple specimens of each lichen species and from symbionts of other fungi and plants, as well as from free-living strains of Nostoc and related genera of cyanobacteria. The genus Nostoc comprises two divergent lineages, but symbiotic strains occur primarily within a single monophyletic lineage that also includes free-living representatives. Cyanobacteria from the same lichen species were often more closely related to strains from other species or to plant symbionts or free-living strains than to each other. These results indicate that host specialization is low for the genus Nostoc, and suggest that opportunities for coevolution with its partners may be rare.

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Allele-specific PCR shows that genetic exchange occurs among genetically diverse Nodularia (Cyanobacteria) filaments in the Baltic Sea

Cited by 56 publications

References 32 publications

Benthic cyanobacteria of the genus Nodularia are non-toxic, without gas vacuoles, able to glide and genetically more diverse than planktonic Nodularia

Benthic cyanobacteria of the genus Nodularia are non-toxic, without gas vacuoles, able to glide and genetically more diverse than planktonic Nodularia

Morphometric variability of the genus Nodularia (Cyanobacteria) in Baltic natural communities

Assessing host specialization in symbiotic cyanobacteria associated with four closely related species of the lichen fungusPeltigera

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