GENETIC DIVERSITY WITHIN BALTIC SEA POPULATIONS OF NODULARIA (CYANOBACTERIA)¹

Abstract

The determination of the genetic structure of microbial populations has, until recently, required the establishment of many independent clonal cultures for genotypic analysis. I n such studies it has been necessaly to assume that isolates able to grow in laboratoly culture are representative of the full range of diversity within the natural population. I n order to test this assumption we used the polymerase chain reaction (PCR) to amp@ the intergenic spacer regzon of the Phycocyanin operon (PGIGS) fiom $laments of Nodularia taken both from clonal cultures and from natural populations in the Baltic Sea. Analysis of the nucleotide sequences revealed more variation among 16 cultured isolates than within 23 single$laments sampled fiom a natural population. As a means of rapidly determining p o p ulation genetic structure we designed and used mixtures of allele-specijic amplification primers in diagnostic PCRs to identifj which PGIGS allele was present in single$laments from natural cyanobacterial assemblages. Using this method, we determined the PGIGS genotype of 156 $laments from 9 sampling stations throughout the central basin of the Baltic Sea in July 1996. Our results show that two distinct genotypes of Nodularia are present in the population at all stations. Although the two Qpes were present in approximately equal numbers, they were not distributed uniformly.

The diversity of gas vesicle genes in Planktothrix rubescens from Lake Zürich

“…The primers (PCβF and PCαR; Table 1) used for the amplification of part of the phycocyanin operon were those designed by Neilan et al (1995). DNA polymorphisms identified previously within this operon (Neilan et al, 1995 ;Hayes & Barker, 1997) indicated that this may be a useful genetic marker for distinguishing between cyanobacterial species. In Planktothrix strain 9307, PCR amplification resulted in a 695 bp product.…”

Phylogenetic analyses of Synechococcus strains (cyanobacteria) using sequences of 16S rDNA and part of the phycocyanin operon reveal multiple evolutionary lines and reflect phycobilin content.

“…In addition to analysis of 16S rRNA gene sequences (Giovannoni et al, 1988 ;Honda et al, 1999 ;Neilan et al, 1997 ;Otsuka et al, 1998 ;Turner et al, 1999 ;Urbach et al, 1998 ;Wilmotte, 1994), genes encoding the major light-harvesting accessory pigment proteins, particularly the phycocyanin (PC) operon (cpc), including the intergenic spacer (IGS) between cpcB and cpcA and the corresponding flanking regions (cpcBA-IGS), have been targeted for phylogenetic studies of cyanobacteria (Barker et al, 1999 ;Bolch et al, 1996 ;Hayes & Barker, 1997 ;Neilan et al, 1995).…”

Comparison of conserved structural and regulatory domains within divergent 16S rRNA–23S rRNA spacer sequences of cyanobacteria The GenBank accession numbers for the sequences reported in this paper are AF180968 and AF180969 for ITS-L and ITS-S, respectively.

“…Limited data have been obtained from the physical or genetic maps of the unicellular strains Synechococcus PCC 6301 (Tomioka et al, 1981), Synechococcus PCC 7002 (Chen & Widger, 1993) and Synechocystis PCC 6803 (Kaneko et al, 1996). Further information is available from the sequences of the 16S rRNA-23S rRNA ITS domain in members of several cyanobacterial genera that include the unicellular Synechococcus PCC 6301 (Tomioka & Sugiura, 1984), Synechocystis PCC 6803 (Kaneko et al, 1996) and 47 strains of the genus Microcystis (Otsuka et al, 1999), the filamentous (non-heterocystous) Arthrospira PCC 7345 (Nelissen et al, 1994), Spirulina PCC 6313 (Nelissen et al, 1994) and Trichodesmium NIBB 1067 , the heterocystous Nodularia BCNOD 9427 (Hayes & Barker, 1997) and a strain of uncertain generic identity, ' Mastigocladus HTF ' strain PCC 7518 (G. Van der Auwera & A. Wilmotte, personal communication). In addition, the sequence of the ITS of the photosynthetic cyanelle of Cyanophora paradoxa has been determined (Janssen et al, 1987).…”