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Millan A.,University of Santiago de Compostela | Gomez-Tato A.,University of Santiago de Compostela | Pardo B.G.,University of Santiago de Compostela | Fernandez C.,University of Santiago de Compostela | And 7 more authors.
Marine Biotechnology | Year: 2011

We evaluated the expression profiles of turbot in the spleen, liver, and head kidney across five temporal points of the Aeromonas salmonicida infection process using an 8 × 15 K Agilent oligo-microarray. The microarray included 2,176 different fivefold replicated gene probes designed from a turbot 3′ sequenced EST database. We were able to identify 471 differentially expressed (DE) genes (17.3% of the whole microarray), 223 in the spleen, 246 in the liver, and 125 in the head kidney, in at least one of the five temporal points sampled for each organ. Most of these genes could be annotated (83.0%) and functionally categorized using Gene Ontology terms (69.1%) after the additional sequencing of DE genes from the 5′ end. Many DE genes were related to innate and acquired immune functions in accordance to previous studies with this pathogen in other fish species. A high proportion of DE genes were organ specific (77.1%), but their associated GO functions were rather similar in the three organs. The most striking difference in functional distribution was observed between the up- and down-regulated gene groups. Up-regulated genes were mostly associated to key immune functions while down-regulated ones mainly involved metabolism- and transport-related genes. Genetic response appeared clustered in groups of genes with similar expression profiles along the temporal series. The spleen showed the most clustering while the liver and head kidney displayed a higher diversification. The information obtained will aid to understand the turbot immune response and will specifically be valuable to develop strategies of defense to A. salmonicida to achieve more resistant broodstocks for turbot industry. © 2011 Springer Science+Business Media, LLC. Source


Rodriguez-Ramilo S.T.,University of Vigo | Fernandez J.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria | Toro M.A.,Technical University of Madrid | Bouza C.,University of Santiago de Compostela | And 5 more authors.
Animal Genetics | Year: 2013

Disease resistance-related traits have received increasing importance in aquaculture breeding programs worldwide. Currently, genomic information offers new possibilities in breeding to address the improvement of this kind of traits. The turbot is one of the most promising European aquaculture species, and Philasterides dicentrarchi is a scuticociliate parasite causing fatal disease in farmed turbot. An appealing approach to fight against disease is to achieve a more robust broodstock, which could prevent or diminish the devastating effects of scuticociliatosis on farmed individuals. In the present study, a genome scan for quantitative trait loci (QTL) affecting resistance and survival time to P. dicentrarchi in four turbot families was carried out. The objectives were to identify QTL using different statistical approaches [linear regression (LR) and maximum likelihood (ML)] and to locate significantly associated markers for their application in genetic breeding strategies. Several genomic regions controlling resistance and survival time to P. dicentrarchi were detected. When analyzing each family separately, significant QTL for resistance were identified by the LR method in two linkage groups (LG1 and LG9) and for survival time in LG1, while the ML methodology identified QTL for resistance in LG9 and LG23 and for survival time in LG6 and LG23. The analysis of the total data set identified an additional significant QTL for resistance and survival time in LG3 with the LR method. Significant association between disease resistance-related traits and genotypes was detected for several markers, a single one explaining up to 22% of the phenotypic variance. Obtained results will be essential to identify candidate genes for resistance and to apply them in marker-assisted selection programs to improve turbot production. © 2012 The Authors. Source


Rodriguez-Ramilo S.T.,University of Vigo | Toro M.A.,Technical University of Madrid | Bouza C.,University of Santiago de Compostela | Hermida M.,University of Santiago de Compostela | And 4 more authors.
BMC Genomics | Year: 2011

Background: Interactions between fish and pathogens, that may be harmless under natural conditions, often result in serious diseases in aquaculture systems. This is especially important due to the fact that the strains used in aquaculture are derived from wild strains that may not have had enough time to adapt to new disease pressures. The turbot is one of the most promising European aquaculture species. Furunculosis, caused by the bacterium Aeromonas salmonicida, produces important losses to turbot industry. An appealing solution is to achieve more robust broodstock, which can prevent or diminish the devastating effects of epizooties. Genomics strategies have been developed in turbot to look for candidate genes for resistance to furunculosis and a genetic map with appropriate density to screen for genomic associations has been also constructed. In the present study, a genome scan for QTL affecting resistance and survival to A. salmonicida in four turbot families was carried out. The objectives were to identify consistent QTL using different statistical approaches (linear regression and maximum likelihood) and to locate the tightest associated markers for their application in genetic breeding strategies.Results: Significant QTL for resistance were identified by the linear regression method in three linkage groups (LGs 4, 6 and 9) and for survival in two LGs (6 and 9). The maximum likelihood methodology identified QTL in three LGs (5, 6 and 9) for both traits. Significant association between disease traits and genotypes was detected for several markers, some of them explaining up to 17% of the phenotypic variance. We also identified candidate genes located in the detected QTL using data from previously mapped markers.Conclusions: Several regions controlling resistance to A. salmonicida in turbot have been detected. The observed concordance between different statistical methods at particular linkage groups gives consistency to our results. The detected associated markers could be useful for genetic breeding strategies. A finer mapping will be necessary at the detected QTL intervals to narrow associations and around the closely associated markers to look for candidate genes through comparative genomics or positional cloning strategies. The identification of associated variants at specific genes will be essential, together with the QTL associations detected in this study, for future marker assisted selection programs. © 2011 Rodríguez-Ramilo et al; licensee BioMed Central Ltd. Source


Sanchez-Molano E.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria | Cerna A.,Technical University of Madrid | Toro M.A.,Technical University of Madrid | Bouza C.,University of Santiago de Compostela | And 5 more authors.
BMC Genomics | Year: 2011

Background: The turbot (Scophthalmus maximus) is a highly appreciated European aquaculture species. Growth related traits constitute the main goal of the ongoing genetic breeding programs of this species. The recent construction of a consensus linkage map in this species has allowed the selection of a panel of 100 homogeneously distributed markers covering the 26 linkage groups (LG) suitable for QTL search. In this study we addressed the detection of QTL with effect on body weight, length and Fulton's condition factor.Results: Eight families from two genetic breeding programs comprising 814 individuals were used to search for growth related QTL using the panel of microsatellites available for QTL screening. Two different approaches, maximum likelihood and regression interval mapping, were used in order to search for QTL. Up to eleven significant QTL were detected with both methods in at least one family: four for weight on LGs 5, 14, 15 and 16; five for length on LGs 5, 6, 12, 14 and 15; and two for Fulton's condition factor on LGs 3 and 16. In these LGs an association analysis was performed to ascertain the microsatellite marker with the highest apparent effect on the trait, in order to test the possibility of using them for marker assisted selection.Conclusions: The use of regression interval mapping and maximum likelihood methods for QTL detection provided consistent results in many cases, although the high variation observed for traits mean among families made it difficult to evaluate QTL effects. Finer mapping of detected QTL, looking for tightly linked markers to the causative mutation, and comparative genomics are suggested to deepen in the analysis of QTL in turbot so they can be applied in marker assisted selection programs. © 2011 Sánchez-Molano et al; licensee BioMed Central Ltd. Source


Pardo B.G.,University of Santiago de Compostela | Millan A.,University of Santiago de Compostela | Gomez-Tato A.,University of Santiago de Compostela | Fernandez C.,University of Santiago de Compostela | And 6 more authors.
Marine Biotechnology | Year: 2012

We evaluated the expression profiles of turbot in spleen, liver, and head kidney across five temporal points of the Philasterides dicentrarchi infection process using an 8x15K Agilent oligo-microarray. The microarray included 2,176 different fivefold replicated gene probes designed from a turbot 3′ sequenced EST database. We were able to identify 221 differentially expressed (DE) genes (8. 1% of the whole microarray), 113 in spleen, 83 in liver, and 90 in head kidney, in at least 1 of the 5 temporal points sampled for each organ. Most of these genes could be annotated (83. 0%) and functionally categorized using GO terms (69. 1%) after the additional sequencing of DE genes from the 5′ end. Many DE genes were related to innate and acquired immune functions. A high proportion of DE genes were organ-specific (70. 6%), although their associated GO functions showed notable similarities in the three organs. The most striking difference in functional distribution was observed between the up- and downregulated gene groups. Upregulated genes were mostly associated to immune functions, while downregulated ones mainly involved metabolism-related genes. Genetic response appeared clustered in a few groups of genes with similar expression profiles along the temporal series. The information obtained will aid to understand the turbot immune response and will specifically be valuable to develop strategies of defense to P. dicentrarchi to achieve more resistant broodstocks for turbot industry. © 2012 Springer Science+Business Media, LLC. Source

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