Margaret Staton

GDR (Genome Database for Rosaceae): integrated web-database for Rosaceae genomics and genetics data

The Genome Database for Rosaceae (GDR) is a central repository of curated and integrated genetics and genomics data of Rosaceae, an economically important family which includes apple, cherry, peach, pear, raspberry, rose and strawberry. GDR contains annotated databases of all publicly available Rosaceae ESTs, the genetically anchored peach physical map, Rosaceae genetic maps and comprehensively annotated markers and traits. The ESTs are assembled to produce unigene sets of each genus and the entire Rosaceae. Other annotations include putative function, microsatellites, open reading frames, single nucleotide polymorphisms, gene ontology terms and anchored map position where applicable. Most of the published Rosaceae genetic maps can be viewed and compared through CMap, the comparative map viewer. The peach physical map can be viewed using WebFPC/WebChrom, and also through our integrated GDR map viewer, which serves as a portal to the combined genetic, transcriptome and physical mapping information. ESTs, BACs, markers and traits can be queried by various categories and the search result sites are linked to the mapping visualization tools. GDR also provides online analysis tools such as a batch BLAST/FASTA server for the GDR datasets, a sequence assembly server and microsatellite and primer detection tools. GDR is available at http://www.rosaceae.org.

CMD: a Cotton Microsatellite Database resource for Gossypium genomics

BackgroundThe Cotton Microsatellite Database (CMD) http://www.cottonssr.org is a curated and integrated web-based relational database providing centralized access to publicly available cotton microsatellites, an invaluable resource for basic and applied research in cotton breeding.DescriptionAt present CMD contains publication, sequence, primer, mapping and homology data for nine major cotton microsatellite projects, collectively representing 5,484 microsatellites. In addition, CMD displays data for three of the microsatellite projects that have been screened against a panel of core germplasm. The standardized panel consists of 12 diverse genotypes including genetic standards, mapping parents, BAC donors, subgenome representatives, unique breeding lines, exotic introgression sources, and contemporary Upland cottons with significant acreage. A suite of online microsatellite data mining tools are accessible at CMD. These include an SSR server which identifies microsatellites, primers, open reading frames, and GC-content of uploaded sequences; BLAST and FASTA servers providing sequence similarity searches against the existing cotton SSR sequences and primers, a CAP3 server to assemble EST sequences into longer transcripts prior to mining for SSRs, and CMap, a viewer for comparing cotton SSR maps.ConclusionThe collection of publicly available cotton SSR markers in a centralized, readily accessible and curated web-enabled database provides a more efficient utilization of microsatellite resources and will help accelerate basic and applied research in molecular breeding and genetic mapping in Gossypium spp.

GDR (Genome Database for Rosaceae): integrated web resources for Rosaceae genomics and genetics research

BackgroundPeach is being developed as a model organism for Rosaceae, an economically important family that includes fruits and ornamental plants such as apple, pear, strawberry, cherry, almond and rose. The genomics and genetics data of peach can play a significant role in the gene discovery and the genetic understanding of related species. The effective utilization of these peach resources, however, requires the development of an integrated and centralized database with associated analysis tools.DescriptionThe Genome Database for Rosaceae (GDR) is a curated and integrated web-based relational database. GDR contains comprehensive data of the genetically anchored peach physical map, an annotated peach EST database, Rosaceae maps and markers and all publicly available Rosaceae sequences. Annotations of ESTs include contig assembly, putative function, simple sequence repeats, and anchored position to the peach physical map where applicable. Our integrated map viewer provides graphical interface to the genetic, transcriptome and physical mapping information. ESTs, BACs and markers can be queried by various categories and the search result sites are linked to the integrated map viewer or to the WebFPC physical map sites. In addition to browsing and querying the database, users can compare their sequences with the annotated GDR sequences via a dedicated sequence similarity server running either the BLAST or FASTA algorithm. To demonstrate the utility of the integrated and fully annotated database and analysis tools, we describe a case study where we anchored Rosaceae sequences to the peach physical and genetic map by sequence similarity.ConclusionsThe GDR has been initiated to meet the major deficiency in Rosaceae genomics and genetics research, namely a centralized web database and bioinformatics tools for data storage, analysis and exchange. GDR can be accessed at http://www.genome.clemson.edu/gdr/.

Expressed sequence tags (ESTs) and simple sequence repeat (SSR) markers from octoploid strawberry (Fragaria × ananassa)

BackgroundCultivated strawberry (Fragaria × ananassa) represents one of the most valued fruit crops in the United States. Despite its economic importance, the octoploid genome presents a formidable barrier to efficient study of genome structure and molecular mechanisms that underlie agriculturally-relevant traits. Many potentially fruitful research avenues, especially large-scale gene expression surveys and development of molecular genetic markers have been limited by a lack of sequence information in public databases. As a first step to remedy this discrepancy a cDNA library has been developed from salicylate-treated, whole-plant tissues and over 1800 expressed sequence tags (ESTs) have been sequenced and analyzed.ResultsA putative unigene set of 1304 sequences – 133 contigs and 1171 singlets – has been developed, and the transcripts have been functionally annotated. Homology searches indicate that 89.5% of sequences share significant similarity to known/putative proteins or Rosaceae ESTs. The ESTs have been functionally characterized and genes relevant to specific physiological processes of economic importance have been identified. A set of tools useful for SSR development and mapping is presented.ConclusionSequences derived from this effort may be used to speed gene discovery efforts in Fragaria and the Rosaceae in general and also open avenues of comparative mapping. This report represents a first step in expanding molecular-genetic analyses in strawberry and demonstrates how computational tools can be used to optimally mine a large body of useful information from a relatively small data set.

Genomics of Fagaceae

An overview of recent achievements and development of genomic resources in the Fagaceae is provided, with major emphasis on the genera Castanea and Quercus. The Fagaceae is a large plant family comprising more than 900 species belonging to 8–10 genera. Using a wide range of molecular markers, population genetics and gene diversity surveys were the focus of many studies during the past 20xa0years. This work set the stage for investigations in genomics beginning in the early 1990s and facilitated the application of genetic and quantitative trait loci mapping approaches. Transferability of markers across species and comparative mapping have indicated tight macrosynteny between Quercus and Castanea. Omic technologies were more recently developed and the corresponding resources are accessible via electronic and physical repositories (expressed sequence tag sequences, single-nucleotide polymorphisms, candidate genes, cDNA clones, bacterial artificial chromosome (BAC) libraries) that have been installed in North America and Europe. BAC libraries and physical maps were also constructed in Castanea and Quercus and provide the necessary resources for full nuclear genome sequencing projects that are currently under way in Castanea mollissima (Chinese chestnut) and Quercus robur (pedunculate oak).

Synteny conservation between the Prunus genome and both the present and ancestral Arabidopsis genomes

BackgroundDue to the lack of availability of large genomic sequences for peach or other Prunus species, the degree of synteny conservation between the Prunus species and Arabidopsis has not been systematically assessed. Using the recently available peach EST sequences that are anchored to Prunus genetic maps and to peach physical map, we analyzed the extent of conserved synteny between the Prunus and the Arabidopsis genomes. The reconstructed pseudo-ancestral Arabidopsis genome, existed prior to the proposed recent polyploidy event, was also utilized in our analysis to further elucidate the evolutionary relationship.ResultsWe analyzed the synteny conservation between the Prunus and the Arabidopsis genomes by comparing 475 peach ESTs that are anchored to Prunus genetic maps and their Arabidopsis homologs detected by sequence similarity. Microsyntenic regions were detected between all five Arabidopsis chromosomes and seven of the eight linkage groups of the Prunus reference map. An additional 1097 peach ESTs that are anchored to 431 BAC contigs of the peach physical map and their Arabidopsis homologs were also analyzed. Microsyntenic regions were detected in 77 BAC contigs. The syntenic regions from both data sets were short and contained only a couple of conserved gene pairs. The synteny between peach and Arabidopsis was fragmentary; all the Prunus linkage groups containing syntenic regions matched to more than two different Arabidopsis chromosomes, and most BAC contigs with multiple conserved syntenic regions corresponded to multiple Arabidopsis chromosomes. Using the same peach EST datasets and their Arabidopsis homologs, we also detected conserved syntenic regions in the pseudo-ancestral Arabidopsis genome. In many cases, the gene order and content of peach regions was more conserved in the ancestral genome than in the present Arabidopsis region. Statistical significance of each syntenic group was calculated using simulated Arabidopsis genome.ConclusionWe report here the result of the first extensive analysis of the conserved microsynteny using DNA sequences across the Prunus genome and their Arabidopsis homologs. Our study also illustrates that both the ancestral and present Arabidopsis genomes can provide a useful resource for marker saturation and candidate gene search, as well as elucidating evolutionary relationships between species.

Tripal: a construction toolkit for online genome databases

As the availability, affordability and magnitude of genomics and genetics research increases so does the need to provide online access to resulting data and analyses. Availability of a tailored online database is the desire for many investigators or research communities; however, managing the Information Technology infrastructure needed to create such a database can be an undesired distraction from primary research or potentially cost prohibitive. Tripal provides simplified site development by merging the power of Drupal, a popular web Content Management System with that of Chado, a community-derived database schema for storage of genomic, genetic and other related biological data. Tripal provides an interface that extends the content management features of Drupal to the data housed in Chado. Furthermore, Tripal provides a web-based Chado installer, genomic data loaders, web-based editing of data for organisms, genomic features, biological libraries, controlled vocabularies and stock collections. Also available are Tripal extensions that support loading and visualizations of NCBI BLAST, InterPro, Kyoto Encyclopedia of Genes and Genomes and Gene Ontology analyses, as well as an extension that provides integration of Tripal with GBrowse, a popular GMOD tool. An Application Programming Interface is available to allow creation of custom extensions by site developers, and the look-and-feel of the site is completely customizable through Drupal-based PHP template files. Addition of non-biological content and user-management is afforded through Drupal. Tripal is an open source and freely available software package found at http://tripal.sourceforge.net

A physical map of the Chinese chestnut (Castanea mollissima) genome and its integration with the genetic map

Three Chinese chestnut bacterial artificial chromosome (BAC) libraries were developed and used for physical map construction. Specifically, high information content fingerprinting was used to assemble 126,445 BAC clones into 1,377 contigs and 12,919 singletons. Integration of the dense Chinese chestnut genetic map with the physical map was achieved via high-throughput hybridization using overgo probes derived from sequence-based genetic markers. A total of 1,026 probes were anchored to the physical map including 831 probes corresponding to 878 expressed sequence tag-based markers. Within the physical map, three BAC contigs were anchored to the three major fungal blight-resistant quantitative trait loci on chestnut linkage groups B, F, and G. A subset of probes corresponding to orthologous genes in poplar showed only a limited amount of conserved gene order between the poplar and chestnut genomes. The integrated genetic and physical map of Chinese chestnut is available at www.fagaceae.org/physical_maps.

Genomic tools development for Aquilegia: construction of a BAC-based physical map

BackgroundThe genus Aquilegia, consisting of approximately 70 taxa, is a member of the basal eudicot lineage, Ranuculales, which is evolutionarily intermediate between monocots and core eudicots, and represents a relatively unstudied clade in the angiosperm phylogenetic tree that bridges the gap between these two major plant groups. Aquilegia species are closely related and their distribution covers highly diverse habitats. These provide rich resources to better understand the genetic basis of adaptation to different pollinators and habitats that in turn leads to rapid speciation. To gain insights into the genome structure and facilitate gene identification, comparative genomics and whole-genome shotgun sequencing assembly, BAC-based genomics resources are of crucial importance.ResultsBAC-based genomic resources, including two BAC libraries, a physical map with anchored markers and BAC end sequences, were established from A. formosa. The physical map was composed of a total of 50,155 BAC clones in 832 contigs and 3939 singletons, covering 21X genome equivalents. These contigs spanned a physical length of 689.8 Mb (~2.3X of the genome) suggesting the complex heterozygosity of the genome. A set of 197 markers was developed from ESTs induced by drought-stress, or involved in anthocyanin biosynthesis or floral development, and was integrated into the physical map. Among these were 87 genetically mapped markers that anchored 54 contigs, spanning 76.4 Mb (25.5%) across the genome. Analysis of a selection of 12,086 BAC end sequences (BESs) from the minimal tiling path (MTP) allowed a preview of the Aquilegia genome organization, including identification of transposable elements, simple sequence repeats and gene content. Common repetitive elements previously reported in both monocots and core eudicots were identified in Aquilegia suggesting the value of this genome in connecting the two major plant clades. Comparison with sequenced plant genomes indicated a higher similarity to grapevine (Vitis vinifera) than to rice and Arabidopsis in the transcriptomes.ConclusionsThe A. formosa BAC-based genomic resources provide valuable tools to study Aquilegia genome. Further integration of other existing genomics resources, such as ESTs, into the physical map should enable better understanding of the molecular mechanisms underlying adaptive radiation and elaboration of floral morphology.

A genetically anchored physical framework for Theobroma cacao cv. Matina 1-6

BackgroundThe fermented dried seeds of Theobroma cacao (cacao tree) are the main ingredient in chocolate. World cocoa production was estimated to be 3 million tons in 2010 with an annual estimated average growth rate of 2.2%. The cacao bean production industry is currently under threat from a rise in fungal diseases including black pod, frosty pod, and witches broom. In order to address these issues, genome-sequencing efforts have been initiated recently to facilitate identification of genetic markers and genes that could be utilized to accelerate the release of robust T. cacao cultivars. However, problems inherent with assembly and resolution of distal regions of complex eukaryotic genomes, such as gaps, chimeric joins, and unresolvable repeat-induced compressions, have been unavoidably encountered with the sequencing strategies selected.ResultsHere, we describe the construction of a BAC-based integrated genetic-physical map of the T. cacao cultivar Matina 1-6 which is designed to augment and enhance these sequencing efforts. Three BAC libraries, each comprised of 10× coverage, were constructed and fingerprinted. 230 genetic markers from a high-resolution genetic recombination map and 96 Arabidopsis-derived conserved ortholog set (COS) II markers were anchored using pooled overgo hybridization. A dense tile path consisting of 29,383 BACs was selected and end-sequenced. The physical map consists of 154 contigs and 4,268 singletons. Forty-nine contigs are genetically anchored and ordered to chromosomes for a total span of 307.2 Mbp. The unanchored contigs (105) span 67.4 Mbp and therefore the estimated genome size of T. cacao is 374.6 Mbp. A comparative analysis with A. thaliana, V. vinifera, and P. trichocarpa suggests that comparisons of the genome assemblies of these distantly related species could provide insights into genome structure, evolutionary history, conservation of functional sites, and improvements in physical map assembly. A comparison between the two T. cacao cultivars Matina 1-6 and Criollo indicates a high degree of collinearity in their genomes, yet rearrangements were also observed.ConclusionsThe results presented in this study are a stand-alone resource for functional exploitation and enhancement of Theobroma cacao but are also expected to complement and augment ongoing genome-sequencing efforts. This resource will serve as a template for refinement of the T. cacao genome through gap-filling, targeted re-sequencing, and resolution of repetitive DNA arrays.