Detection of Cochlodinium polykrikoides and Gymnodinium impudicum (Dinophyceae) in sediment samples from Korea using real-time PCR

Harmful dinoflagellate blooms caused by Cochlodinium sp.: Global expansion and ecological strategies facilitating bloom formation

“…<10 cells ml À1 ), a phenomenon that has been intractable via traditional, microscopic approaches, and thus is poorly understood. Park and Park (2010) further extended the use of real-time qPCR by analyzing sediment samples for the presence of both C. polykrikoides and G. impudicum in Korean coastal samples. They were unable to attribute the presence of nucleic acids to any specific life stage, however, leading to the possibility that they detected intact cells, resting stages, cysts, or degraded cellular material.…”

“…For C. polykrikoides, the rDNA content per cell is currently unknown, and little is known at this time regarding cyst formation in this species, ruling out a direct calibration of the PCR method with known cyst densities. Despite these issues, Park and Park (2010) demonstrated that realtime qPCR could be used to detect relative abundances (copy number) and geographic distribution of C. polykrikoides sequences in coastal sediments. This in turn provides a useful molecular approach for identifying benthic populations.…”

The toxic dinoflagellate Cochlodinium polykrikoides (Dinophyceae) produces resting cysts

“…The production of cysts by C. polykrikoides that overwinter and germinate to form blooms would account for its ability to form blooms annually in these estuaries. Park and Park (2010) detected C. polykrikoides in surface sediments of the South Sea, Korea, using species-specific real-time polymerase chain reactions (PCR) probes and suggested that C. polykrikoides may persist in the form of cyst in sediments where blooms of C. polykrikoides occur annually. Our results support this supposition.…”

“…Rubino et al (2010) and Mohamed and Al-Shehri (2011) reported the identification and germination of C. polykrikoides cysts from the Red Sea and the Mediterranean, respectively, but, again, the cysts and germlings were not identified unambiguously. Park and Park (2010) detected C. polykrikoides by PCR in sediment samples, suggesting the presence of C. polykrikoides in sediments, but no morphological information was provided and hence the detection of vegetative cells or DNA residues of vegetative cells could not be excluded. C.-H. Kim et al (2002) reported on the production of hyaline cysts from cultivated C. polykrikoides bloom water while C.-J.…”

Mapping the Distribution of Cysts from the Toxic Dinoflagellate Cochlodinium polykrikoides in Bloom-Prone Estuaries by a Novel Fluorescence In Situ Hybridization Assay

“…Low cyst densities quantified 6 months after high-density blooms may be indicative of a small portion of the vegetative population being involved in sexual reproduction (57), grazing of cysts in sediments (58,59), bacterial degradation of cysts (10), and/or the movement of cysts/vegetative cells out of the bloom region via currents (60) and subsequent deposition of cysts elsewhere (61). Currently, there is only one other report of Cochlodinium cysts in sediments; however, abundances were reported in rDNA copies per cubic centimeter of wet sediment and thus not comparable (40). In regard to excystment, like Cochlodinium, other cyst-forming dinoflagellates such as Alexandrium can also produce highdensity blooms (Ͼ10 6 cells liter Ϫ1 ) from low-density cyst beds (Ͻ50 cysts cm Ϫ3 [57,62]).…”