Complete Genome Sequence of Ralstonia solanacearum WR-1, a Virulent Strain on Solanum lycopersicum.

Ralstonia solanacearum is a bacterial wilt pathogen of Solanum lycopersicum. Its pathogenicity is the result of coevolution during continuous interaction with its host plants under given biotic and abiotic environments. To elucidate clues for pathogenicity of our WR-1 strain, its genome sequence was analyzed.

Complete Genome Sequence of Ralstonia pseudosolanacearum Strain Sw698, Isolated from Solanum lycopersicum.

Ralstonia pseudosolanacearum is a member of the Ralstonia solanacearum species complex (RSSC), which is composed of three species and diverse subspecific groups. Some strains cause bacterial wilt in Solanum lycopersicum; others are beneficial for their hosts. Herein, we present the complete genome sequence of an RSSC strain, Sw698, beneficial for S. lycopersicum growth.

Complete Genome Sequence of Ralstonia solanacearum Strain Bs715, a Member of Biovar 4 and a Strong Pathogen of Bacterial Wilt on Solanum lycopersicum.

Ralstonia solanacearum is a notorious pathogen of bacterial wilt on Solanum lycopersicum. Most isolates from diseased tomato tissues are biovar 3, and their genomes are publicly available; however, information on biovar 4 strains is limited. Here, the complete genome sequence of R. solanacearum Bs715, a biovar 4 strain, is presented.

Rice transcription factor WRKY114 directly regulates the expression of OsPR1a and Chitinase to enhance resistance against Xanthomonas oryzae pv. oryzae.

Rice (Oryza sativa L.) is a global staple crop, but its yield is severely threatened by bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo). The OsWRKY transcription factor family play a central role in innate plant immunity against Xoo, but the various biological functions of a large number of OsWRKYs remain to be understood. We characterized the role of OsWRKY114 against Xoo. OsWRKY114 has transcriptional activity in yeast and localizes in the nucleus. When OsWRKY114 is overexpressed in transgenic plants they show enhanced disease resistance against Xoo compared with wild types. By using genetic- and cell-based functional analyses, we showed OsWRKY114 directly associates with the promoters of OsPR1a and Chitinase and increases the promoter activities. These results suggest that OsWRKY114 enhances the innate immunity of Asian rice against Xoo through direct activation of defense genes that include OsPR1a and chtinase. This is the first report to functionally characterize OsWRKY114 in Xoo infection.

NGS_SNPAnalyzer: a desktop software supporting genome projects by identifying and visualizing sequence variations from next-generation sequencing data.

BACKGROUND: Sequence variations such as single nucleotide polymorphisms are markers for genetic diseases and breeding. Therefore, identifying sequence variations is one of the main objectives of several genome projects. Although most genome project consortiums provide standard operation procedures for sequence variation detection methods, there may be differences in the results because of human selection or error. OBJECTIVE: To standardize the procedure for sequence variation detection and help researchers who are not formally trained in bioinformatics, we developed the NGS_SNPAnalyzer, a desktop software and fully automated graphical pipeline. METHODS: The NGS_SNPAnalyzer is implemented using JavaFX (version 1.8); therefore, it is not limited to any operating system (OS). The tools employed in the NGS_SNPAnalyzer were compiled on Microsoft Windows (version 7, 10) and Ubuntu Linux (version 16.04, 17.0.4). RESULTS: The NGS_SNPAnalyzer not only includes the functionalities for variant calling and annotation but also provides quality control, mapping, and filtering details to support all procedures from next-generation sequencing (NGS) data to variant visualization. It can be executed using pre-set pipelines and options and customized via user-specified options. Additionally, the NGS_SNPAnalyzer provides a user-friendly graphical interface and can be installed on any OS that supports JAVA. CONCLUSIONS: Although there are several pipelines and visualization tools available for NGS data analysis, we developed the NGS_SNPAnalyzer to provide the user with an easy-to-use interface. The benchmark test results indicate that the NGS_SNPAnayzer achieves better performance than other open source tools.

Re-exploration of U's Triangle Brassica Species Based on Chloroplast Genomes and 45S nrDNA Sequences.

The concept of U's triangle, which revealed the importance of polyploidization in plant genome evolution, described natural allopolyploidization events in Brassica using three diploids [B. rapa (A genome), B. nigra (B), and B. oleracea (C)] and derived allotetraploids [B. juncea (AB genome), B. napus (AC), and B. carinata (BC)]. However, comprehensive understanding of Brassica genome evolution has not been fully achieved. Here, we performed low-coverage (2-6×) whole-genome sequencing of 28 accessions of Brassica as well as of Raphanus sativus [R genome] to explore the evolution of six Brassica species based on chloroplast genome and ribosomal DNA variations. Our phylogenomic analyses led to two main conclusions. (1) Intra-species-level chloroplast genome variations are low in the three allotetraploids (2~7 SNPs), but rich and variable in each diploid species (7~193 SNPs). (2) Three allotetraploids maintain two 45SnrDNA types derived from both ancestral species with maternal dominance. Furthermore, this study sheds light on the maternal origin of the AC chloroplast genome. Overall, this study clarifies the genetic relationships of U's triangle species based on a comprehensive genomics approach and provides important genomic resources for correlative and evolutionary studies.

The complete chloroplast genome of two Brassica species, Brassica nigra and B. Oleracea.

The two Brassica species, Brassica nigra and Brassica oleracea, are important agronomic crops. The chloroplast genome sequences were generated by de novo assembly using whole genome next-generation sequences. The chloroplast genomes of B. nigra and B. oleracea were 153 633 bp and 153 366 bp in size, respectively, and showed conserved typical chloroplast structure. The both chloroplast genomes contained a total of 114 genes including 80 protein-coding genes, 30 tRNA genes, and 4 rRNA genes. Phylogenetic analysis revealed that B. oleracea is closely related to B. rapa and B. napus but B. nigra is more diverse than the neighbor species Raphanus sativus.

A Multilayered Screening Method for the Identification of Regulatory Genes in Rice by Agronomic Traits.

We developed a multilayered screening method that integrates both genome and transcriptome data to effectively identify regulatory genes in rice (Oryza sativa). We tested our method using eight rice accessions that differed in three important nutritional and agricultural traits, anthocyanin biosynthesis, amylose content, and heading date. In the genome resequencing of eight rice accessions with 24 RNA sequencing experiments, 98% of the preprocessed reads could be uniquely mapped to the reference genome, resulting in the identification of 42,699 unique transcripts. Comparison between black and white rice cultivars showed evidence of intensive selective sweeps in chromosomes 3, 10, and 12. A total of 131 genes were differentially expressed among the black rice cultivars and found to be associated with three Gene Ontology terms (secondary metabolic process, biosynthetic process, and response to stimulus). We identified nonsynonymous Single Nucleotide Polymorphism (SNP) that likely play an important role in determining the agronomic traits differences, two upregulated and three downregulated genes in the black cultivars, and two downregulated genes in the white cultivars. The three agronomic traits were clearly grouped together by the developmental stages, regardless of any other traits, suggesting that the developmental stage is the most important factor that triggers global changes in gene expression. Interestingly, glutinous and nonglutinous black rice cultivars were distinguished from one another by different heading dates.

Elucidating the triplicated ancestral genome structure of radish based on chromosome-level comparison with the Brassica genomes.

KEYMESSAGE: This study presents a chromosome-scale draft genome sequence of radish that is assembled into nine chromosomal pseudomolecules. A comprehensive comparative genome analysis with the Brassica genomes provides genomic evidences on the evolution of the mesohexaploid radish genome. Radish (Raphanus sativus L.) is an agronomically important root vegetable crop and its origin and phylogenetic position in the tribe Brassiceae is controversial. Here we present a comprehensive analysis of the radish genome based on the chromosome sequences of R. sativus cv. WK10039. The radish genome was sequenced and assembled into 426.2 Mb spanning >98 % of the gene space, of which 344.0 Mb were integrated into nine chromosome pseudomolecules. Approximately 36 % of the genome was repetitive sequences and 46,514 protein-coding genes were predicted and annotated. Comparative mapping of the tPCK-like ancestral genome revealed that the radish genome has intermediate characteristics between the Brassica A/C and B genomes in the triplicated segments, suggesting an internal origin from the genus Brassica. The evolutionary characteristics shared between radish and other Brassica species provided genomic evidences that the current form of nine chromosomes in radish was rearranged from the chromosomes of hexaploid progenitor. Overall, this study provides a chromosome-scale draft genome sequence of radish as well as novel insight into evolution of the mesohexaploid genomes in the tribe Brassiceae.

NABIC: A New Access Portal to Search, Visualize, and Share Agricultural Genomics Data.

The National Agricultural Biotechnology Information Center developed an access portal to search, visualize, and share agricultural genomics data with a focus on South Korean information and resources. The portal features an agricultural biotechnology database containing a wide range of omics data from public and proprietary sources. We collected 28.4 TB of data from 162 agricultural organisms, with 10 types of omics data comprising next-generation sequencing sequence read archive, genome, gene, nucleotide, DNA chip, expressed sequence tag, interactome, protein structure, molecular marker, and single-nucleotide polymorphism datasets. Our genomic resources contain information on five animals, seven plants, and one fungus, which is accessed through a genome browser. We also developed a data submission and analysis system as a web service, with easy-to-use functions and cutting-edge algorithms, including those for handling next-generation sequencing data.

NABIC SNP: an integrated database for SNP markers.

UNLABELLED: The National Agricultural Biotechnology Information Center (NABIC) constructed a web-based database to provide information about 54,310 single nucleotide polymorphisms (SNPs) identified in the seven species in a high-throughput manner. The database consists of three major functional categories: SNP marker search, detailed information viewer and download of SNP sequence. The SNP annotation table provides detailed information such as ownership information, basic information, bio-entry information, reference, comments, features, and sequence data. AVAILABILITY: The database is available online for free at http://nabic.rda.go.kr/SNP.

Whole-genome resequencing and transcriptomic analysis to identify genes involved in leaf-color diversity in ornamental rice plants.

Rice field art is a large-scale art form in which people design rice fields using various kinds of ornamental rice plants with different leaf colors. Leaf color-related genes play an important role in the study of chlorophyll biosynthesis, chloroplast structure and function, and anthocyanin biosynthesis. Despite the role of different metabolites in the traditional relationship between leaf and color, comprehensive color-specific metabolite studies of ornamental rice have been limited. We performed whole-genome resequencing and transcriptomic analysis of regulatory patterns and genetic diversity among different rice cultivars to discover new genetic mechanisms that promote enhanced levels of various leaf colors. We resequenced the genomes of 10 rice leaf-color accessions to an average of 40× reads depth and >95% coverage and performed 30 RNA-seq experiments using the 10 rice accessions sampled at three developmental stages. The sequencing results yielded a total of 1,814 × 106 reads and identified an average of 713,114 SNPs per rice accession. Based on our analysis of the DNA variation and gene expression, we selected 47 candidate genes. We used an integrated analysis of the whole-genome resequencing data and the RNA-seq data to divide the candidate genes into two groups: genes related to macronutrient (i.e., magnesium and sulfur) transport and genes related to flavonoid pathways, including anthocyanidin biosynthesis. We verified the candidate genes with quantitative real-time PCR using transgenic T-DNA insertion mutants. Our study demonstrates the potential of integrated screening methods combined with genetic-variation and transcriptomic data to isolate genes involved in complex biosynthetic networks and pathways.

RiceQTLPro: an integrated database for quantitative trait loci marker mapping in rice plant.

UNLABELLED: The National Agricultural Biotechnology Information Center (NABIC) in South Korea reconstructed a RiceQTLPro database for gene positional analysis and structure prediction of the chromosomes. This database is an integrated web-based system providing information about quantitative trait loci (QTL) markers in rice plant. The RiceQTLPro has the three main features namely, (1) QTL markers list, (2) searching of markers using keyword, and (3) searching of marker position on the rice chromosomes. This updated database provides 112 QTL markers information with 817 polymorphic markers on each of the 12 chromosomes in rice. AVAILABILITY: The database is available for free at http://nabic.rda.go.kr/gere/rice/geneticMap/

AllergenPro: an integrated database for allergenicity analysis and prediction.

UNLABELLED: The National Agricultural Biotechnology Information Center (NABIC) reconstructed an AllergenPro database for allergenic proteins analysis and allergenicity prediction. The AllergenPro is an integrated web-based system providing information about allergen in foods, microorganisms, animals and plants. The allergen database has the three main features namely, (1) allergen list with epitopes, (2) searching of allergen using keyword, and (3) methods for allergenicity prediction. This updated AllergenPro outputs the search based allergen information through a user-friendly web interface, and users can run tools for allergenicity prediction using three different methods namely, (1) FAO/WHO, (2) motif-based and (3) epitope-based methods. AVAILABILITY: The database is available for free at http://nabic.rda.go.kr/allergen/

A Multi-Layered Screening Method to Identify Plant Regulatory Genes.

We used a seven-step process to identify genes involved in glucosinolate biosynthesis and metabolism in the Chinese cabbage (Brassica rapa). We constructed an annotated data set with 34,570 unigenes from B. rapa and predicted 11,526 glucosinolate-related candidate genes using expression profiles generated across nine stages of development on a 47k-gene microarray. Using our multi-layered screening method, we screened 392 transcription factors, 843 pathway genes, and 4,162 ortholog genes associated with glucosinolate-related biosynthesis. Finally, we identified five genes by comparison of the pathway-network genes including the transcription-factor genes and the ortholog-ontology genes. The five genes were anchored to the chromosomes of B. rapa to characterize their genetic-map positions, and phylogenetic reconstruction with homologous genes was performed. These anchored genes were verified by reverse-transcription polymerase chain reaction. While the five genes identified by our multi-layered screen require further characterization and validation, our study demonstrates the power of multi-layered screening after initial identification of genes on microarrays.

NABIC marker database: A molecular markers information network of agricultural crops.

UNLABELLED: In 2013, National Agricultural Biotechnology Information Center (NABIC) reconstructs a molecular marker database for useful genetic resources. The web-based marker database consists of three major functional categories: map viewer, RSN marker and gene annotation. It provides 7250 marker locations, 3301 RSN marker property, 3280 molecular marker annotation information in agricultural plants. The individual molecular marker provides information such as marker name, expressed sequence tag number, gene definition and general marker information. This updated marker-based database provides useful information through a user-friendly web interface that assisted in tracing any new structures of the chromosomes and gene positional functions using specific molecular markers. AVAILABILITY: The database is available for free at http://nabic.rda.go.kr/gere/rice/molecularMarkers/

Draft genome sequence of the biocontrol bacterium Bacillus amyloliquefaciens strain M27.

Bacillus amyloliquefaciens strain M27 is a biocontrol agent with antagonistic activities against a wide range of fungal pathogens. Here we present the 3.86-Mb draft genome sequence of the bacterium with the aims of providing insights into the genomic basis of its antifungal mechanism and facilitating its application in the biocontrol of plant diseases.

A quantitative and direct PCR assay for the subspecies-specific detection of Clavibacter michiganensis subsp. michiganensis based on a ferredoxin reductase gene.

The Gram-positive bacterium Clavibacter michiganensis subsp. michiganensis is the causal agent of canker disease in tomato. Because it is very important to control newly introduced inoculum sources from commercial materials, the specific detection of this pathogen in seeds and seedlings is essential for effective disease control. In this study, a novel and efficient assay for the detection and quantitation of C. michiganensis subsp. michiganensis in symptomless tomato and red pepper seeds was developed. A pair of polymerase chain reaction (PCR) primers (Cmm141F/R) was designed to amplify a specific 141 bp fragment on the basis of a ferredoxin reductase gene of C. michiganensis subsp. michiganensis NCPPB 382. The specificity of the primer set was evaluated using purified DNA from 16 isolates of five C. michiganensis subspecies, one other Clavibacter species, and 17 other reference bacteria. The primer set amplified a single band of expected size from the genomic DNA obtained from the C. michiganensis subsp. michiganensis strains but not from the other C. michiganensis subspecies or from other Clavibacter species. The detection limit was a single cloned copy of the ferredoxin reductase gene of C. michiganensis subsp. michiganensis. In conclusion, this quantitative direct PCR assay can be applied as a practical diagnostic method for epidemiological research and the sanitary management of seeds and seedlings with a low level or latent infection of C. michiganensis subsp. michiganensis.

Comparative mapping, genomic structure, and expression analysis of eight pseudo-response regulator genes in Brassica rapa.

Circadian clocks regulate plant growth and development in response to environmental factors. In this function, clocks influence the adaptation of species to changes in location or climate. Circadian-clock genes have been subject of intense study in models such as Arabidopsis thaliana but the results may not necessarily reflect clock functions in species with polyploid genomes, such as Brassica species, that include multiple copies of clock-related genes. The triplicate genome of Brassica rapa retains high sequence-level co-linearity with Arabidopsis genomes. In B. rapa we had previously identified five orthologs of the five known Arabidopsis pseudo-response regulator (PRR) genes that are key regulators of the circadian clock in this species. Three of these B. rapa genes, BrPRR1, BrPPR5, and BrPPR7, are present in two copies each in the B. rapa genome, for a total of eight B. rapa PRR (BrPRR) orthologs. We have now determined sequences and expression characteristics of the eight BrPRR genes and mapped their positions in the B. rapa genome. Although both members of each paralogous pair exhibited the same expression pattern, some variation in their gene structures was apparent. The BrPRR genes are tightly linked to several flowering genes. The knowledge about genome location, copy number variation and structural diversity of these B. rapa clock genes will improve our understanding of clock-related functions in this important crop. This will facilitate the development of Brassica crops for optimal growth in new environments and under changing conditions.

A physical map of Brassica oleracea shows complexity of chromosomal changes following recursive paleopolyploidizations.

BACKGROUND: Evolution of the Brassica species has been recursively affected by polyploidy events, and comparison to their relative, Arabidopsis thaliana, provides means to explore their genomic complexity. RESULTS: A genome-wide physical map of a rapid-cycling strain of B. oleracea was constructed by integrating high-information-content fingerprinting (HICF) of Bacterial Artificial Chromosome (BAC) clones with hybridization to sequence-tagged probes. Using 2907 contigs of two or more BACs, we performed several lines of comparative genomic analysis. Interspecific DNA synteny is much better preserved in euchromatin than heterochromatin, showing the qualitative difference in evolution of these respective genomic domains. About 67% of contigs can be aligned to the Arabidopsis genome, with 96.5% corresponding to euchromatic regions, and 3.5% (shown to contain repetitive sequences) to pericentromeric regions. Overgo probe hybridization data showed that contigs aligned to Arabidopsis euchromatin contain ~80% of low-copy-number genes, while genes with high copy number are much more frequently associated with pericentromeric regions. We identified 39 interchromosomal breakpoints during the diversification of B. oleracea and Arabidopsis thaliana, a relatively high level of genomic change since their divergence. Comparison of the B. oleracea physical map with Arabidopsis and other available eudicot genomes showed appreciable 'shadowing' produced by more ancient polyploidies, resulting in a web of relatedness among contigs which increased genomic complexity. CONCLUSIONS: A high-resolution genetically-anchored physical map sheds light on Brassica genome organization and advances positional cloning of specific genes, and may help to validate genome sequence assembly and alignment to chromosomes.All the physical mapping data is freely shared at a WebFPC site (http://lulu.pgml.uga.edu/fpc/WebAGCoL/brassica/WebFPC/; Temporarily password-protected: account: pgml; password: 123qwe123.