Geographic distribution ofPfiesteriaspp. (Pfiesteriaceae) in Tasman Bay and Canterbury, New Zealand (2002–03)

Abstract

The fish-killing heterotrophic dinoflagellate species Pfiesteria piscicida and P. shumwayae (also Pseudopfiesteria shumwayae)were present throughout New Zealand and were residents of Tasman Bay's well-flushed estuaries and Canterbury's brackish lakes, as determined by polymerase chain reaction-based detection assays. The two species occurred in a wide range of salinities and temperatures, although detection was restricted seasonally from spring through to autumn, except for one incidence in the shallow waters of Wairewa/ Lake Forsyth, Canterbury, in the winter of 2003. The DNA sequencing data indicated that P. shumwayae may encompass a suite of genetically closely related species. The presence of Pfiesteria in New Zealand is not considered an immediate risk to fish or human health given the current low-to-moderate nutrient concentrations in New Zealand's estuaries and brackish lakes. However, increases in nutrient loadings could pose a risk, as has occurred in eastern United States estuaries.

Morphological and molecular genetic characterization of Cryptoperidiniopsis brodyi (Dinophyceae) from Australia-wide isolates

“…Early distribution studies have reported that P. shumwayae has been detected on every continent, including multiple locations of the U.S., Australia and New Zealand, which imply that this species is cosmopolitan (Rublee et al, 2001Rhodes et al, 2002Rhodes et al, , 2006Bowers et al, 2006;Tango et al, 2006). However, the false positive PCR reactions with Australian genotypes of C. brodyi suggested that genetically related species had been misidentified as P. shumwayae and the geographic range of this species might have been overestimated in Australia and other counties.…”

“…Sequences of environmental clones (GenBank accession nos. DQ387443-9, DQ401157) amplified using P. shumwayae-selective primers showed a considerable divergence (4%) from P. shumwayae (Rhodes et al, 2006;Rublee et al, 2006), and those sequences did not match with Australian genotypes of C. brodyi or other related species indicating cross-reactivity with unknown species. These findings suggest that previous P. shumwayae identifications in Australian estuaries were most probably C. brodyi and not P. shumwayae.…”

“…The crossreactivity with Australian genotypes means that SSU rDNA regions are not suitable for the development of accurate PCR assays specific to P. shumwayae, indicating potential false-positive reactions with other genetically related species as well as C. brodyi due to lower divergence rate between species in the SSU rDNA regions. Recent studies (Rhodes et al, 2006;Rublee et al, 2006) also reported that non-specific amplifications can be produced by P. shumwayae-specific primers based on SSU rDNA when applied to environmental samples. Sequences of environmental clones (GenBank accession nos.…”

Development of a Real-Time PCR Probe for Quantification of the Heterotrophic Dinoflagellate Cryptoperidiniopsis brodyi (Dinophyceae) in Environmental Samples

“…The finding of C. brodyi in the Chapman River confirms that this species is widely distributed and commonly present in Australia. P. shumwayae has been detected previously on every continent by using molecular probes based on SSU rDNA, suggesting that P. shumwayae is a cosmopolitan species (4,28,29,30,31,32,33,39). In Australia, this species was detected in various locations in Queensland, South Australia, Victoria, Western Australia, and Tasmania (P. A. Rublee, personal communication).…”

Detection of a novel ecotype of Pfiesteria piscicida (Dinophyceae) in an Antarctic saline lake by real-time PCR

“…The P. shumwayae-specific primer set and the P. piscicida-specific primer-probe set were previously designed from mitochondrial cytochrome b gene (cob) (Zhang and Lin 2005) and from SSU rDNA (Bowers et al 2000), respectively ( Table 1). Specificity of these assays has been tested against other related species and has been confirmed by sequence analysis of PCR amplicons from natural waters (Bowers et al 2000;Zhang and Lin 2005;Rhodes et al 2006). Prior to use of both real-time PCR assays for Antarctic water samples, specificity was also tested with Australian genotypes of Cryptoperidiniopsis brodyi (CBWA12, CBSA4, CBHU1, CBDE1, and CBDE10) because these sequences were not available when these assays were developed.…”