title: Molecular analysis of bacterial microbiota associated with oysters (Crassostrea gigas and Crassostrea corteziensis) in different growth phases at two cultivation sites.
abstract: Microbiota presumably plays an essential role in inhibiting pathogen colonization and in the maintenance of health in oysters, but limited data exist concerning their different growth phases and conditions. We analyzed the bacterial microbiota composition of two commercial oysters: Crassostrea gigas and Crassostrea corteziensis. Differences in microbiota were assayed in three growth phases: post-larvae at the hatchery, juvenile, and adult at two grow-out cultivation sites. Variations in the microbiota were assessed by PCR analysis of the 16S rRNA gene in DNA extracted from depurated oysters. Restriction fragment length polymorphism (RFLP) profiles were studied using Dice's similarity coefficient (Cs) and statistical principal component analysis (PCA). The microbiota composition was determined by sequencing temperature gradient gel electrophoresis (TGGE) bands. The RFLP analysis of post-larvae revealed homology in the microbiota of both oyster species (Cs > 88 %). Dice and PCA analyses of C. corteziensis but not C. gigas showed differences in the microbiota according to the cultivation sites. The sequencing analysis revealed low bacterial diversity (primarily β-Proteobacteria, Firmicutes, and Spirochaetes), with Burkholderia cepacia being the most abundant bacteria in both oyster species. This study provides the first description of the microbiota in C. corteziensis, which was shown to be influenced by cultivation site conditions. During early growth, we observed that B. cepacia colonized and remained strongly associated with the two oysters, probably in a symbiotic host-bacteria relationship. This association was maintained in the three growth phases and was not altered by environmental conditions or the management of the oysters at the grow-out site.
authors.affiliation: Centro de Investigaciones Biológicas del Noroeste, (CIBNOR), Mar Bermejo 195, Col. Playa Palo de Santa Rita, La Paz, Baja California Sur, 23095, Mexico. natitrabal@gmail.com
authors.forename: Natalia
authors.initials: N
authors.lastname: Trabal
authors.forename: José M
authors.initials: JM
authors.lastname: Mazón-Suástegui
authors.forename: Ricardo
authors.initials: R
authors.lastname: Vázquez-Juárez
authors.forename: Felipe
authors.initials: F
authors.lastname: Asencio-Valle
authors.forename: Enrique
authors.initials: E
authors.lastname: Morales-Bojórquez
authors.forename: Jaime
authors.initials: J
authors.lastname: Romero
mesh_terms: D000818:Animals; D017756:Aquaculture; D001419:Bacteria / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D016956:Burkholderia cepacia / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D049896:Crassostrea / Q000254:growth & development* / Q000382:microbiology*; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D058645:Denaturing Gradient Gel Electrophoresis; D054892:Metagenome; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction / Q000379:methods; D012150:Polymorphism, Restriction Fragment Length; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S