Polymorphism at the ITS and NTS Loci ofPerkinsus marinusIsolated from Cultivated OysterCrassostrea corteziensisin Nayarit, Mexico and Phylogentic Relationship toP. marinusalong the Atlantic Coast

Abstract

Prevalence of the protozoan Perkinsus spp. in the gills of the pleasure oyster Crassostrea corteziensis from two estuaries in Nayarit, Mexico, was measured. The protozoan was identified by PCR amplification of the internal transcribed spacer (ITS) region of the rDNA of Perkinsus spp. The pathogen was found in 92% of oysters from Boca de Camichín and 77% of oysters from Pozo Chino. ITS sequences characterized from C. corteziensis showed 96-100% similarity to Perkinsus marinus. The most frequent ITS sequence (GenBank JQ266236) had 100% identity with the ITS locus of P. marinus from New Jersey, Maryland, South Carolina and Texas, and the second most frequent observed sequence (GenBank JQ266240) was 100% identical to ITS sequences of P. marinus from New Jersey, South Carolina, Louisiana, and Bahía Kino, Sonora, Mexico. The 14 sequences from the non-transcribed spacer (NTS) showed 98% similarity to P. marinus from Texas. The most frequent polymorphism identified was at nucleotide 446 of the ITS region; however, the NTS showed the highest nucleotide diversity, thereby suggesting that this region is suitable for genotype identification. Moreover, the most conserved ITS marker is better for species-specific diagnosis. Both the ITS and NTS sequences of P. marinus obtained from C. corteziensis were grouped in two clades, identifying two allelic variants of P. marinus.

OsHV 1 and notifiable protozoa in healthy Crassostrea corteziensis cultured in two distant areas of the Gulf of California

“…The presence in the south area since the first sampling, and the increasing prevalence in subsequent surveys, suggests a large population of P. marinus established in that area, but at the end of the study the prevalence was 96% in both locations. Escobedo-Fregoso et al (2015) reported high prevalence of P. marinus in C. corteziensis in two locations of Nayarit during the summer, indicating a match with our high number of carrier oysters, so it will not be uncommon to find high prevalence values anywhere in the Gulf of California.…”

“…In 1997, oyster massive mortalities were recorded for the first time in Mexico in the states of Sonora, Baja California and Baja California Sur in juvenile and early adult oyster (Maeda-Martínez, 2008) which caused production to behave erratically in subsequent years. Moreover, in the Gulf of California it has been detected ostreid herpesvirus type 1 or OsHV-1 (Vásquez-Yeomans et al, 2004, 2010Grijalva-Chon et al, 2013), Perkinsus marinus Enríquez-Espinoza et al, 2010Villanueva-Fonseca & Escobedo-Bonilla, 2013, Escobedo-Fregoso et al, 2015 and recently Marteilia refringens .…”

Two epizootic Perkinsus spp. events in commercial oyster farms at Santa Catarina, Brazil

“…in both oyster species was confirmed by molecular analysis (Figure ) in 100% of analysed sample for Pacific (4 [4]) and native oysters (4 [4]) from São Francisco do Sul and native oyster from Balneário Barra do Sul (2 [2]). Sequencing results (Table ) of all the products amplified from DNA samples of C. gigas and C. gasar from São Francisco do Sul showed identical sequences (100% of similarity) when compared to themselves and to sequences deposited in the NCBI identified as P. marinus (Figure ), such as the isolate CBMA79 (access code KP160922), found in the State of Paraíba, Brazil (Queiroga et al, ), and MEX‐47NW DC (JQ266249), found in Mexico (Escobedo‐Fregoso et al, ). Also, the sequences identified as Perkinsus beihaiensis in C. gasar from Balneário Barra do Sul showed 100% of similarity among themselves and with sequences deposited in the NCBI.…”

Research Article Molecular detection of the pathogenic protist <i>Perkinsus</i> <i>marinus</i> in farmed native and introduced oysters (<i>Crassostrea</i> spp.) in southern Brazil

“…Based on Escobedo-Fregoso et al 2012, the NTS region is considered to be a better marker for P. marinus genotype identification due to its higher nucleotide diversity when compared to the ITS region. Consequently, the more conserved region of the ITS can be used for species discrimination (Escobedo-Fregoso et al, 2012).…”

“…and in adult C. gigas from the state of Santa Catarina. Furthermore, we studied the parasite phylogenetic intraspecific variability based on its rDNA non-internal transcriber spacer (NTS) region that is suggested to be a marker for P. marinus genotyping (Escobedo-Fregoso et al, 2012). A molecular characterization of P. marinus in different geographical locations would facilitate a better understanding of the parasite's epidemiology.…”