Intra-specific phenotypic and genotypic variation in toxic cyanobacterial Microcystis strains.
OBJECTIVE
We determined if the intra-specific genetic diversity of Microcystis aeruginosa correlates with phenotypic characteristics.


RESULTS
Microcystis aeruginosa isolates from various Japanese waters were characterized using genetic analyses based on the 16S-23S rDNA internal transcribed spacer (ITS) region and DNA-independent RNA polymerase (rpoC1) gene sequences. In addition, morphological and biochemical properties, and the toxicity of M. aeruginosa strains were determined. We found a correlation in phylogenetic clusters of the ITS region and rpoC1 gene sequences. Using a polyphasic approach, genotypic and phenotypic variations in M. aeruginosa showed that the three genetic lineage groups are comprised of a particular phenotype or subgroup of closely related phenotypes. However, some strains had high phenotypic and genotypic diversity compared to the three lineage groups and did not show distinct lineages; therefore, these strains were designated as the 'complex group'.


CONCLUSIONS
The 'complex group' consisted of genetically and phenotypically incoherent and high diverse populations in M. aeruginosa, although some genotypes or lineages displayed consistent phenotypes.


CONCLUSIONS
The polyphasic approach combining phenotypic and genetic characterization was effective for comprehending distinct lineages and discriminating the potential complexity of M. aeruginosa populations at the intra-species level.
Yoshida
M
M
Department of Marine Bioscience, Fukui Prefectural University, Obama-City, Fukui, Japan. yoshiten@fpu.ac.jp
Yoshida
T
T
Satomi
M
M
Takashima
Y
Y
Hosoda
N
N
Hiroishi
S
S
D021903:DNA, Ribosomal Spacer / Q000032:analysis; D005068:Eutrophication; D005618:Fresh Water; D014644:Genetic Variation; D005838:Genotype; D046931:Microcystis / Q000145:classification* / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D021521:Ribotyping; D014871:Water Microbiology
D021903:DNA, Ribosomal Spacer; D012336:RNA, Ribosomal, 16S