Project description:The cultivated peanut, A. hypogaea L., is a critical oil and food crop worldwide. Decoding the genetic makeup behind natural variation in kernel oil and fatty acid concentrations is crucial for molecular breeding-based nutrient quantity and quality manipulation. Herein, we recognized 87 quantitative trait loci (QTLs) in 45 genomic regions for the concentrations of oil, oleic acid, and linoleic acid, as well as the oleic acid to linoleic acid (O/L) ratio via a genome-wide association study (GWAS) involving 499 peanut accessions. Eight QTLs clarified over 15% of the phenotypic variation in peanut accessions. Among the 45 potential genes significantly related to the 4 traits, only three genes displayed annotation to the fatty acid pathway. Furthermore, on the basis of pleiotropism or linkage data belonging to the identified singular QTLs, we generated a trait-locus axis to better elucidate the genetic background behind the observed oil and fatty acid concentration association. Together, our results provide strong evidence for the genetic mechanism behind oil biosynthesis in A. hypogaea L., facilitating future advances in multiple fatty acid component generation via pyramiding of desirable QTLs This natural population consisting of 499 peanut accessions combined with high-density SNPs will provide a better choice for identifying peanut QTLs/genes in the future. Together, our results provide strong evidence for the genetic mechanism behind oil biosynthesis in peanut, facilitating future advances in multiple fatty acid component generation via pyramiding of desirable QTLs.
Project description:A mRNA expression study has been performed 20-25 minutes postmortem obtained samples from Longissimus dorsi muscle of 59 Duroc x LD/LW pigs to search for gene sequences related to meat quality (pH24, pH45, “Lab” colour coordinates, curing yield and exudation at three different times) or to meat composition (intramuscular fat, content of several fatty acid (C16:0, C18:0, C18:1 and C18:2), ratio of saturated, monounsaturated and polyunsaturated fatty acids, and protein and humidity contents) traits in order to find targets for selection. Gene ontology analysis, biological pathways and gene networks studies all show, that many more differentially expressed genes (506 vs 279) are related to meat quality (Group P, or perimortem characters) than to meat composition traits (Group L, or whole life traits). The difference between the number of GO terms annotated, biological pathways and gene networks in groups P and L is notable due to the differences in the complexity of the “generation process” of P-traits and the involvement of other tissues or organs in the generation of variability of L-traits. Also, interactions between a list of differentially expressed genes were found in ECM-receptor interaction, TGF-beta signaling pathway, fatty acid elongation in mitochondria and adipocytokine signalling pathway indicating that a substantial fraction of the gene networks could be associated with interactions between differential expressed genes related to traits under study. A high number of the most overexpressed genes are related to muscle development and functionality and repair mechanisms; they could be good candidates for breeding programs whose main goal is to enhance meat quality. 59 Longissimus Dorsi samples from 59 LD/LW x Duroc cross. A total of 33 traits on composition, conformation and meat quality and compositional traits were recorded in the left Longissimus dorsi muscle.
Project description:The molecular targets of SRC-2 regulation in the murine liver stimulate fatty acid degradation and glycolytic pathway while fatty acid, cholesterol, and steroid biosynthetic pathways are down-regulated. A genomic approach using microarray analysis was employed to identify the subsets of genes that are altered in the liver of SRC-2-/- mice.
Project description:In sheep, differences were observed regarding fat accumulation and fatty acid composition between males and females, which may impact the quality and organoleptic characteristics of the meat. The analysis of omics technologies is a relevant approach for investigating biological and genetic mechanisms associated with complex traits. Here, the perirenal tissue of six male and six female Assaf suckling lambs was evaluated using RNA sequencing.
Project description:In pigs, adipose tissue is one of the principal organs involved in the regulation of lipid metabolism. It is particulary involved in the overall fatty acid synthesis with consequences in other lipid-target organs such as muscles and the liver. With this in mind, we have used massive, parallel high-throughput sequencing technologies to characterize the porcine adipose tissue transcriptome architecture in six Iberian x Landrace crossbred pigs showing extreme phenotypes for intramuscular fatty acid composition (three per group). High-throughput RNA sequencing was used to generate a whole characterization of adipose tissue (backfat) transcriptome. A total of 4,130 putative unannotated protein-coding sequences were identified in the 20% of reads which mapped in intergenic regions. Furthermore, 36% of the unmapped reads were represented by interspersed repeats, SINEs being the most abundant elements. Differential expression analyses identified 396 candidate genes among divergent animals for intramuscular fatty acid composition. Sixty-two percent of these genes (247/396) presented higher expression in the group of pigs with higher content of intramuscular SFA and MUFA, while the remaining 149 showed higher expression in the group with higher content of PUFA. Pathway analysis related these genes to biological functions and canonical pathways controlling lipid and fatty acid metabolisms. In concordance with the phenotypic classification of animals, the major metabolic pathway differentially modulated between groups was de novo lipogenesis, the group with more PUFA being the one that showed lower expression of lipogenic genes. These results will help in the identification of genetic variants at loci that affect fatty acid composition traits. The implications of these results range from the improvement of porcine meat quality traits to the application of the pig as an animal model of human metabolic diseases. The supplementary files contains the five arrays reported in the paper. Backfat from five animals were assayed with high-density oligonucleotide microarray chips (GeneChipM-BM-. Porcine) from Affymetrix, in order to validate RNA-Seq data.
Project description:A mRNA expression study has been performed 20-25 minutes postmortem obtained samples from Longissimus dorsi muscle of 59 Duroc x LD/LW pigs to search for gene sequences related to meat quality (pH24, pH45, “Lab” colour coordinates, curing yield and exudation at three different times) or to meat composition (intramuscular fat, content of several fatty acid (C16:0, C18:0, C18:1 and C18:2), ratio of saturated, monounsaturated and polyunsaturated fatty acids, and protein and humidity contents) traits in order to find targets for selection. Gene ontology analysis, biological pathways and gene networks studies all show, that many more differentially expressed genes (506 vs 279) are related to meat quality (Group P, or perimortem characters) than to meat composition traits (Group L, or whole life traits). The difference between the number of GO terms annotated, biological pathways and gene networks in groups P and L is notable due to the differences in the complexity of the “generation process” of P-traits and the involvement of other tissues or organs in the generation of variability of L-traits. Also, interactions between a list of differentially expressed genes were found in ECM-receptor interaction, TGF-beta signaling pathway, fatty acid elongation in mitochondria and adipocytokine signalling pathway indicating that a substantial fraction of the gene networks could be associated with interactions between differential expressed genes related to traits under study. A high number of the most overexpressed genes are related to muscle development and functionality and repair mechanisms; they could be good candidates for breeding programs whose main goal is to enhance meat quality.
Project description:Here, we identified a long-chain acyl-CoA-responsive transcriptional repressor, FdmR, as the key regulator of mycobacterial fatty acid catabolism. We employed ChIP-Seq to identify the genomic binding regions for FdmR. FdmR was found to bind upstream of fadA2, fabG4, fadE24, fixA, MMAR_1683, fadE5, icl, desA3, desA3_1, and MMAR_2730.We then demonstrated that FdmR acts as a valve to direct the fatty acid flux from β-oxidation towards lipid biosynthesis, thereby avoiding the overactive catabolism and accumulation of biologically toxic intermediates. This regulatory mechanism enables a high rate of cell growth with modest consumption of fatty acid substrates.
Project description:Systematic analyses of the temporal dynamics of transcriptomes and chromatin landscapes of macrophages during timecourse of TLR4-mediated inflammatory response. As a multifunctional effector cell, macrophages play pivotal roles in both the induction and resolution components of varied inflammatory processes. During the course of an inflammation response, macrophages engage in a homeostatic program characterized by tightly coordinated modulation of temporal outputs of both lipid metabolism and inflammation. We demonstrate inversely biphasic temporal dynamics of specific fatty acid metabolic and inflammatory gene expression profiles, associated with concordant temporal reprogramming of macrophage fatty acid profiles. In part, the late phase of the macrophage inflammatory response is characterized by tailoring of fatty acid related gene expressions, facilitating both significant induction of anti-inflammatory unsaturated fatty acid production and associated resolution of inflammation. We demonstrate the biphasic temporal dynamics of macrophage inflammation, specifically anti-inflammatory omega-3 and omega-9 unsaturated fatty acid levels, are transcriptionally driven genome-wide by an unexpected shift from an LXR to SREBP1-dominant regulatory program in the late phase inflammatory response. Collectively, our findings reveal a novel Srebp1-driven mechanism allowing the intimate inverse temporal relationship between the transcriptional regulation of inflammatory and fatty acid metabolic outputs; whereby modulation key transcriptional regulators (LXR, SREBP1 and NF-kB) of these pathways coordinate appropriate temporal tailoring of local enhancer associated reprogramming and eventual pathway regulatory interactions, during the course of TLR4-dependent inflammatory response in macrophages. This specific Srebp-driven, temporal reprogramming of macrophage fatty acid metabolism, characterized by late phase induction of anti-inflammatory unsaturated fatty acid production, is necessary for appropriate resolution of inflammation. Thus, this study suggests that selective reprogramming of macrophage lipid metabolism can serve as a viable therapeutic intervention aimed at ameliorating chronic inflammation and varied metabolic syndrome associated states.
Project description:In pigs, adipose tissue is one of the principal organs involved in the regulation of lipid metabolism. It is particulary involved in the overall fatty acid synthesis with consequences in other lipid-target organs such as muscles and the liver. With this in mind, we have used massive, parallel high-throughput sequencing technologies to characterize the porcine adipose tissue transcriptome architecture in six Iberian x Landrace crossbred pigs showing extreme phenotypes for intramuscular fatty acid composition (three per group). High-throughput RNA sequencing was used to generate a whole characterization of adipose tissue (backfat) transcriptome. A total of 4,130 putative unannotated protein-coding sequences were identified in the 20% of reads which mapped in intergenic regions. Furthermore, 36% of the unmapped reads were represented by interspersed repeats, SINEs being the most abundant elements. Differential expression analyses identified 396 candidate genes among divergent animals for intramuscular fatty acid composition. Sixty-two percent of these genes (247/396) presented higher expression in the group of pigs with higher content of intramuscular SFA and MUFA, while the remaining 149 showed higher expression in the group with higher content of PUFA. Pathway analysis related these genes to biological functions and canonical pathways controlling lipid and fatty acid metabolisms. In concordance with the phenotypic classification of animals, the major metabolic pathway differentially modulated between groups was de novo lipogenesis, the group with more PUFA being the one that showed lower expression of lipogenic genes. These results will help in the identification of genetic variants at loci that affect fatty acid composition traits. The implications of these results range from the improvement of porcine meat quality traits to the application of the pig as an animal model of human metabolic diseases. The supplementary files contains the five arrays reported in the paper.
Project description:The integration of the results of QTL fine-mapping with microarray expression data offers a promising tool for understanding the genetic mechanisms influencing complex traits as fatty acid composition in pigs. The expression level of each probe may be treated as a quantitative trait and the marker genotypes used to map loci with regulatory effect on the gene expression level (eQTL) According to our previous linkage results, we carry out an eQTL scan focused on chromosomal regions showing tissue-consistent effects on fatty acids with Longissimus dorsi gene expression data in order to detect potentional candidate genes underlying the QTL previously detected. 102 IberianxLandrace backcross pigs were selected for RNA extraction and hybridization on Affymetrix microarrays. An eQTL scan was carried out with the data of 470 probes of the microarray taking into account they were related with fatty acid metabolism