Species‐specific PCR assays for Gambierdiscus excentricus and Gambierdiscus silvae (Gonyaulacales, Dinophyceae)

Abstract

The two most toxic Gambierdiscus species identified from the Caribbean are G. excentricus and G. silvae. These species are the primary causes of ciguatera fish poisoning and likely contribute disproportionately to the toxicity of marine food webs. While Gambierdiscus species are difficult to distinguish using light or scanning electron microscopy, reliable species‐specific molecular identification methods have been developed and used successfully to identify a number of other Gambierdiscus species. Corresponding species‐specific assays are not yet available for G. excentricus and G. silvae, which imposes limitations on species identification and related ecological studies. The following note describes species‐specific polymerase chain reaction assays for G. excentricus and G. silvae that can be used for these purposes.

Report of the Expert Meeting on Ciguatera Poisoning

“…In addition, PCR assays have been published for: G. lapillus (Kretzschmar et al, 2017), G. scabrosus, Fukuyoa cf. yasumotoi (Nishimura et al, 2016); and G. excentricus and G. silvae (Litaker, Tester and Vandersea, 2019).…”

“…Australia (Kohli et al, 2014b) Kiribati (Xu et al, 2014) 0.89 fg CTX3C N2A (Litaker et al, 2017) (Vandersea et al, 2012) Gambierdiscus ribotype 2 (Litaker et al, 2009) Belize, Central America, Caribbean Sea 6.62 fg CTX3C N2A (Litaker et al, 2017) (Vandersea et al, 2012) F. ruetzleri (Litaker et al, 2009;Gomez et al, 2015) Belize, Central America, Caribbean Sea 10.6 fg CTXC3 N2A (Litaker et al, 2017) (Vandersea et al, 2012) G. excentricus (Fraga et al, 2011) Canary Islands, eastern Atlantic Ocean 469 fg CTX3C N2A (Litaker et al, 2017) (Litaker, Tester et al, 2020) G. silvae (Fraga and Rodriguez, 2014) Canary Islands, eastern Atlantic Ocean 19.6 fg CTX3C N2A (Litaker et al, 2017) (Litaker, Tester and Vandersea, 2019) F. paulensis (Gomez et al, 2015) Ubatuba, Sao Paolo State, Brazil neg N2A (Gomez et al, 2015) G. balechii (Fraga et al, 2016) Celebes Sea, South Pacific Kiribati (Dai et al, 2017) 1.1-19.9 fg CTX1B (Dai et al, 2017) G. cheloniae (Smith et al, 2016) Cook Islands, South Pacific Ocean MBA +, no CTX3C (Smith et al, 2016) G. lapillus (Kretzschmar et al, 2017) Great Barrier Reef, Australia MBA +, no CTX (Kretzschmar et al, 2017) ( Kretzschmar et al, 2017) G. scabrosus (Nishimura et al, 2014) Kashiwa-jima Island off southern Honahu, Japan 20 MU/1 000 cells+ (Nishimura et al, 2013) (Formerly Ribotype 1) (Nishimura et al, 2016) G. honu (Rhodes et al, 2017a) Cook Islands & Kermadec Islands, South Paci...…”

Ciguatera poisonings: A global review of occurrences and trends

“…Gambierdiscus excentricus, found at depths of 60 m (Litaker et al, 2019) on Pulley Ridge reef in the eastern Gulf of Mexico, ranges as far north as 29.21°N, in the Canary Islands. There it has been associated with reports of CP after consumption of locally sourced fish since the early 2000s (Pérez-Arellano et al, 2005;Boada et al, 2010;Otero et al, 2010;Bravo et al, 2015;Núñez-Vázquez et al, 2019;Sanchez-Henao et al, 2019;Sanchez-Henao et al, 2020).…”

Ciguatoxin Occurrence in Food-Web Components of a Cuban Coral Reef Ecosystem: Risk-Assessment Implications

“…The DNA extracts were eluted from the mini columns using 50 µL of elution buffer and stored at 4 • C. DNA was screened for the presence of G. belizeanus, G. caribaeus, G. carolinianus, G. carpenteri, F. ruetzleri, G. silvae, G. excentricus, and Gambierdiscus sp. ribotype 2 using the species-specific PCR primers described in Vandersea et al [58] and Litaker et al [59]. The samples were also screened for the presence of G. australes, G. pacificus, G. polynesiensis, and G. toxicus, which served as negative controls since these taxa have not yet been found in the Caribbean region.…”