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News Article | May 1, 2017
Site: phys.org

Catfish is an important dietary protein source and is the third most commonly farmed fish worldwide. While more than 2,500 species of catfish are known to exist, the channel catfish dominates U.S. aquaculture, accounting for more than 60 percent of fish and seafood production. In 2015, production sales for U.S. catfish growers totaled $361 million, up 3 percent from the previous year, according to USDA's National Agricultural Statistics Service. Research at the Agricultural Research Service (ARS) Warmwater Aquaculture Research Unit (WARU) in Stoneville, Mississippi, helps catfish producers improve the quality and quantity of their products. Recently, a team led by WARU molecular biologist Geoff Waldbieser and Auburn University scientist John Liu produced the first genome-sequence assembly for the channel catfish. It's also the first for any type of catfish. The total complement of DNA in the cell is called the "genome," and the catfish genome, like an instruction manual, contains the information needed to make and "operate" each fish. The catfish genome-sequence assembly gives scientists the ability to read the instruction manual for each individual catfish and look for differences that make some animals grow faster or resist disease better. Waldbieser used a special breeding technique called "gynogenesis" to produce the genome donor, Coco, so that she contained two copies of DNA—like other animals—except that both copies were completely identical. "I named her after Coco Chanel, because she's Channel No. 1," Waldbieser says. Collaborating with ARS scientists at the Genomics and Bioinformatics Research Unit in Stoneville and the Bovine Functional Genomics Laboratory in Beltsville, Maryland, Waldbieser produced about 800 million DNA sequences from Coco's DNA. "Those sequences were like puzzle pieces. It took 2 months on a 64-processor computer workstation to align them and produce the genome assembly," Waldbieser says. Waldbieser and WARU geneticist Brian Bosworth recently used Coco's genome to identify variation in DNA sequences between individual catfish within the Delta Select line—an improved catfish line being developed at WARU for use by farmers. "Now that we know where the genetic variations in the DNA sequences are located, we will be able to analyze different parts of the genome inherited by different individual catfish," Waldbieser says. "We can identify those segments, propagate them to our fish population, and improve meat production and production efficiency for farmers." This is important, because improving catfish growth rate, fillet yield, meat quality, and disease resistance will greatly benefit fish farmers, Waldbieser adds. More information: Qifan Zeng et al. Development of a 690 K SNP array in catfish and its application for genetic mapping and validation of the reference genome sequence, Scientific Reports (2017). DOI: 10.1038/srep40347


PubMed | Food and Feed Safety Research Unit, Genomics and Bioinformatics Research Unit, Commodity Utilization Research Unit and Crop Germplasm Research Unit
Type: | Journal: Planta | Year: 2016

Some naturally occurring cotton accessions contain commercially attractive seed oil fatty acid profiles. The likely causal factor for a high-oleate trait in pima cotton ( Gossypium barbadense ) accession GB-713 is described here. Vegetable oils are broadly used in the manufacture of many human and animal nutritional products, and in various industrial applications. Along with other well-known edible plant oils from soybean, corn, and canola, cottonseed oil is a valuable commodity. Cottonseed oil is a co-product derived from the processing of cottonseed fiber. In the past, it was used extensively in a variety of food applications. However, cottonseed oil has lost market share in recent years due to less than optimal ratios of the constituent fatty acids found in either traditional or partially hydrogenated oil. Increased awareness of the negative health consequences of dietary trans-fats, along with the public wariness associated with genetically modified organisms has created high demand for naturally occurring oil with high monounsaturate/polyunsaturate ratios. Here, we report the discovery of multiple exotic accessions of pima cotton that contain elevated seed oil oleate content. The genome of one such accession was sequenced, and a mutant candidate fatty acid desaturase-2 (FAD2-1D) gene was identified. The mutant protein produced significantly less linoleic acid in infiltrated Arabidopsis leaf assays, compared to a repaired version of the same enzyme. Identification of this gene provides a valuable resource. Development of markers associated with this mutant locus will be very useful in efforts to breed the high-oleate trait into agronomic fiber accessions of upland cotton.


PubMed | International Institute Of Tropical Agriculture, Genomics and Bioinformatics Research Unit, Louisiana State University, National Center for Genome Resources and Agrobiodiversity research area
Type: Journal Article | Journal: PloS one | Year: 2015

Current advances in sequencing technologies and bioinformatics revealed the genomic background of rice, a staple food for the poor people, and provided the basis to develop large genomic variation databases for thousands of cultivars. Proper analysis of this massive resource is expected to give novel insights into the structure, function, and evolution of the rice genome, and to aid the development of rice varieties through marker assisted selection or genomic selection. In this work we present sequencing and bioinformatics analyses of 104 rice varieties belonging to the major subspecies of Oryza sativa. We identified repetitive elements and recurrent copy number variation covering about 200 Mbp of the rice genome. Genotyping of over 18 million polymorphic locations within O. sativa allowed us to reconstruct the individual haplotype patterns shaping the genomic background of elite varieties used by farmers throughout the Americas. Based on a reconstruction of the alleles for the gene GBSSI, we could identify novel genetic markers for selection of varieties with high amylose content. We expect that both the analysis methods and the genomic information described here would be of great use for the rice research community and for other groups carrying on similar sequencing efforts in other crops.


Buriev Z.T.,Academy of Sciences of Uzbekistan | Saha S.,U.S. Department of Agriculture | Abdurakhmonov I.Y.,Academy of Sciences of Uzbekistan | Jenkins J.N.,U.S. Department of Agriculture | And 3 more authors.
Theoretical and Applied Genetics | Year: 2010

MIC-3 is a recently identified gene family shown to exhibit increased root-specific expression following nematode infection of cotton plants that are resistant to root-knot nematode. Here, we cloned and sequenced MIC-3 genes from selected diploid and tetraploid cotton species to reveal sequence differences at the molecular level and identify chromosomal locations of MIC-3 genes in Gossypium species. Detailed sequence analysis and phylogenetic clustering of MIC-3 genes indicated the presence of multiple MIC-3 gene members in Gossypium species. Haplotypes of a MIC-3 gene family member were discovered by comparative analysis among consensus sequences across genotypes within an individual clade in the phylogram to overcome the problem of duplicated loci in the tetraploid cotton. Deficiency tests of the SNPs delimited six At-genome members of the MIC-3 family clustered to chromosome arm 4sh, and one Dt-genome member to chromosome 19. Clustering was confirmed by long-PCR amplification of the intergenic regions using At-genome-specific MIC-3 primer pairs. The clustered distribution may have been favored by selection for responsiveness to evolving disease and/or pest pressures, because large variants of the MIC-3 gene family may have been recovered from small physical areas by recombination. This could give a buffer against selection pressure from a broad range of pest and pathogens in the future. To our knowledge, these are the first results on the evolution of clustering and genome-specific haplotype members of a unique cotton gene family associated with resistant response against a major pathogen. © Springer-Verlag 2009.


Perera O.P.,U.S. Department of Agriculture | Blanco C.A.,U.S. Department of Agriculture | Ballard L.,Genomics and Bioinformatics Research Unit | Silva-Brandao K.L.,University of Sao Paulo | And 2 more authors.
Southwestern Entomologist | Year: 2011

Polymorphic genetic markers were identified and characterized using a partial genomic library of the tobacco budworm, Heliothis virescens (Fabricius), enriched for simple sequence repeats (SSR) and nucleotide sequences of expressed sequence tags (EST). Nucleotide sequences of 192 clones from the partial genomic library yielded 147 unique SSRs while EST evaluations identified 280 SSR-containing sequences. All anonymous SSRs and 192 EST-SSRs were evaluated to select loci that produced the best quality peaks without stutter peaks. Six anonymous markers and nine EST-derived markers were selected to evaluate a sample of 96 insects collected from Stoneville, MS. The observed number of alleles ranged from two to eight, with an average of 5.87 (SE ± 0.53). The polymorphic information content (PIC) value averaged 0.446 (SE ± 0.052). Significant deviations from Hardy-Weinberg expectations were detected at eight loci. We speculate that these loci are under selection in the population of tobacco budworm used in the study. No significant linkage disequilibrium was detected at any of the loci. Proportions of anonymous and EST-SSR markers validated after extensive evaluation were 4.08 and 4.68%, respectively. One anonymous SSR marker (HvMS117) and all nine EST markers were transferable to the bollworm, Helicoverpa zea (Boddie). Copyright © 2011 BioOne All rights reserved.


Motamayor J.C.,Mars Incorporated | Mockaitis K.,Indiana University | Schmutz J.,Mars Incorporated | Schmutz J.,HudsonAlpha Institute for Biotechnology | And 30 more authors.
Genome Biology | Year: 2013

Background: Theobroma cacao L. cultivar Matina 1-6 belongs to the most cultivated cacao type. The availability of its genome sequence and methods for identifying genes responsible for important cacao traits will aid cacao researchers and breeders.Results: We describe the sequencing and assembly of the genome of Theobroma cacao L. cultivar Matina. 1-6. The genome of the Matina 1-6 cultivar is 445 Mbp, which is significantly larger than a sequenced Criollo cultivar, and more typical of other cultivars. The chromosome-scale assembly, version 1.1, contains 711 scaffolds covering 346.0 Mbp, with a contig N50 of 84.4 kbp, a scaffold N50 of 34.4 Mbp, and an evidence-based gene set of 29,408 loci. Version 1.1 has 10x the scaffold N50 and 4x the contig N50 as Criollo, and includes 111 Mb more anchored sequence. The version 1.1 assembly has 4.4% gap sequence, while Criollo has 10.9%. Through a combination of haplotype, association mapping and gene expression analyses, we leverage this robust reference genome to identify a promising candidate gene responsible for pod color variation. We demonstrate that green/red pod color in cacao is likely regulated by the R2R3 MYB transcription factor TcMYB113, homologs of which determine pigmentation in Rosaceae, Solanaceae, and Brassicaceae. One SNP within the target site for a highly conserved trans-acting siRNA in dicots, found within TcMYB113, seems to affect transcript levels of this gene and therefore pod color variation.Conclusions: We report a high-quality sequence and annotation of Theobroma cacao L. and demonstrate its utility in identifying candidate genes regulating traits. © 2013 Motamayor et al.; licensee BioMed Central Ltd.


Day J.M.,U.S. Department of Agriculture | Ballard L.L.,Genomics and Bioinformatics Research Unit | Duke M.V.,Genomics and Bioinformatics Research Unit | Scheffler B.E.,Genomics and Bioinformatics Research Unit | Zsak L.,U.S. Department of Agriculture
Virology Journal | Year: 2010

Viral enteric disease is an ongoing economic burden to poultry producers worldwide, and despite considerable research, no single virus has emerged as a likely causative agent and target for prevention and control efforts. Historically, electron microscopy has been used to identify suspect viruses, with many small, round viruses eluding classification based solely on morphology. National and regional surveys using molecular diagnostics have revealed that suspect viruses continuously circulate in United States poultry, with many viruses appearing concomitantly and in healthy birds. High-throughput nucleic acid pyrosequencing is a powerful diagnostic technology capable of determining the full genomic repertoire present in a complex environmental sample. We utilized the Roche/454 Life Sciences GS-FLX platform to compile an RNA virus metagenome from turkey flocks experiencing enteric disease. This approach yielded numerous sequences homologous to viruses in the BLAST nr protein database, many of which have not been described in turkeys. Our analysis of this turkey gut RNA metagenome focuses in particular on the turkey-origin members of the Picornavirales, the Caliciviridae, and the turkey Picobirnaviruses. © 2010 Dayet al licensee BioMed Central Ltd.


Blacklock B.J.,Indiana University – Purdue University Indianapolis | Scheffler B.E.,Genomics and Bioinformatics Research Unit | Shepard M.R.,Indiana University – Purdue University Indianapolis | Jayasuriya N.,Indiana University – Purdue University Indianapolis | Minto R.E.,Indiana University – Purdue University Indianapolis
Journal of Biological Chemistry | Year: 2010

Acetylenic specialized metabolites containing one or more carbon-carbon triple bonds are widespread, being found in fungi, vascular and lower plants, marine sponges and algae, and insects. Plants, moss, and most recently, insects, have been shown to employ an energetically difficult, sequential dehydrogenation mechanism for acetylenic bond formation. Here, we describe the cloning and heterologous expression in yeast of a linoleoyl 12-desaturase (acetylenase) and a bifunctional desaturase with Δ12-/Δ14- regiospecificity from the Pacific golden chanterelle. The acetylenase gene, which is the first identified from a fungus, is phylogenetically distinct from known plant and fungal desaturases. Together, the bifunctional desaturase and the acetylenase provide the enzymatic activities required to drive oleate through linoleate to crepenynate and the conjugated enyne (14Z)- dehydrocrepenynate, the branchpoint precursors to a major class of acetylenic natural products. © 2010 by The American Society for Biochemistry and Molecular Biology, Inc.

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