Alternaria brassicicola causes dark spot (or black spot) disease, which is one of the most common and destructive fungal diseases of Brassicaceae spp. worldwide. Here, we report the draft genome sequence of strain Abra43. The assembly comprises 29 scaffolds, with an N50 value of 2.1 Mb. The assembled genome was 31,036,461 bp in length, with a G+C content of 50.85%.
Powdery mildew resistance genePm4b, originating fromTriticum persicum, is effective against the prevalentBlumeria graminisf. sp.tritici(Bgt) isolates from certain regions of wheat production in China. The lack of tightly linked molecular markers with the target gene prevents the precise identification ofPm4bduring the application of molecular marker-assisted selection (MAS). The strategy that combines the RNA-Seq technique and the bulked segregant analysis (BSR-Seq) was applied in an F2:3mapping population (237 families) derived from a pair of isogenic lines VPM1/7*Bainong 3217 F4(carryingPm4b) and Bainong 3217 to develop more closely linked molecular markers. RNA-Seq analysis of the two phenotypically contrasting RNA bulks prepared from the representative F2:3families generated 20,745,939 and 25,867,480 high-quality read pairs, and 82.8 and 80.2% of them were uniquely mapped to the wheat whole genome draft assembly for the resistant and susceptible RNA bulks, respectively. Variant calling identified 283,866 raw single nucleotide polymorphisms (SNPs) and InDels between the two bulks. The SNPs that were closely associated with the powdery mildew resistance were concentrated on chromosome 2AL. Among the 84 variants that were potentially associated with the disease resistance trait, 46 variants were enriched in an about 25 Mb region at the distal end of chromosome arm 2AL. FourPm4b-linked SNP markers were developed from these variants. Based on the sequences of Chinese Spring where these polymorphic SNPs were located, 98 SSR primer pairs were designed to develop distal markers flanking thePm4bgene. Three SSR markers,Xics13,Xics43, andXics76, were incorporated in the new genetic linkage map, which locatedPm4bin a 3.0 cM genetic interval spanning a 6.7 Mb physical genomic region. This region had a collinear relationship withBrachypodium distachyonchromosome 5, rice chromosome 4, and sorghum chromosome 6. Seven genes associated with disease resistance were predicted in this collinear genomic region, which included C2 domain protein, peroxidase activity protein, protein kinases of PKc_like super family, Mlo family protein, and catalytic domain of the serine/threonine kinases (STKc_IRAK like super family). The markers developed in the present study facilitate identification ofPm4bduring its MAS practice.
The 14-3-3 gene family members play key roles in various cellular processes. However, little is known about the numbers and roles of 14-3-3 genes in wheat. The aims of this study were to identify TaGF14 numbers in wheat by searching its whole genome through blast, to study the phylogenetic relationships with other plant species and to discuss the functions of TaGF14s. The results showed that common wheat harbored 20 TaGF14 genes, located on wheat chromosome groups 2, 3, 4, and 7. Out of them, eighteen TaGF14s are non-e proteins, and two wheat TaGF14 genes, TaGF14i and TaGF14f, are e proteins. Phylogenetic analysis indicated that these genes were divided into six clusters: cluster 1 (TaGF14d, TaGF14g, TaGF14j, TaGF14h, TaGF14c, and TaGF14n); cluster 2 (TaGF14k); cluster 3 (TaGF14b, TaGF14l, TaGF14m, and TaGF14s); cluster 4 (TaGF14a, TaGF14e, and TaGF14r); cluster 5 (TaGF14i and TaGF14f); and cluster 6 (TaGF14o, TaGF14p, TaGF14q, and TaGF14t). Tissue-specific gene expressions suggested that all TaGF14s were likely constitutively expressed, except two genes, i.e., TaGF14p and TaGF14f. And the highest amount of TaGF14 transcripts were observed in developing grains at 20 days post anthesis (DPA), especially for TaGF14j and TaGF14l. After drought stress, five genes, i.e., TaGF14c, TaGF14d, TaGF14g, TaGF14h, and TaGF14j, were up-regulated expression under drought stress for both 1 and 6 h, suggesting these genes played vital role in combating against drought stress. However, all the TaGF14s were down-regulated expression under heat stress for both 1 and 6 h, indicating TaGF14s may be negatively associated with heat stress by reducing the expression to combat heat stress or through other pathways. These results suggested that cluster 1, e.g., TaGF14j, may participate in the whole wheat developing stages, e.g., grain-filling (starch biosynthesis) and may also participate in combating against drought stress. Subsequently, a homolog of TaGF14j, TaGF14-JM22, were cloned by RACE and used to validate its function. Immunoblotting results showed that TaGF14-JM22 protein, closely related to TaGF14d, TaGF14g, and TaGF14j, can interact with AGP-L, SSI, SSII, SBEIIa, and SBEIIb in developing grains, suggesting that TaGF14s located on group 4 may be involved in starch biosynthesis. Therefore, it is possible to develop starch-rich wheat cultivars by modifying TaGF14s.
Urinary tract infections (UTIs) are among the most common infections in humans, predominantly caused by uropathogenic Escherichia coli (UPEC). The diverse genomes of UPEC strains mostly impede disease prevention and control measures. In this study, we comparatively analyzed the whole genome sequence of a highly virulent UPEC strain, namely UPEC 26-1, which was isolated from urine sample of a patient suffering from UTI in Korea. Whole genome analysis showed that the genome consists of one circular chromosome of 5,329,753 bp, comprising 5064 protein-coding genes, 122 RNA genes (94 tRNA, 22 rRNA and 6 ncRNA genes), and 100 pseudogenes, with an average G+C content of 50.56%. In addition, we identified 8 prophage regions comprising 5 intact, 2 incomplete and 1 questionable ones and 63 genomic islands, suggesting the possibility of horizontal gene transfer in this strain. Comparative genome analysis of UPEC 26-1 with the UPEC strain CFT073 revealed an average nucleotide identity of 99.7%. The genome comparison with CFT073 provides major differences in the genome of UPEC 26-1 that would explain its increased virulence and biofilm formation. Nineteen of the total GIs were unique to UPEC 26-1 compared to CFT073 and nine of them harbored unique genes that are involved in virulence, multidrug resistance, biofilm formation and bacterial pathogenesis. The data from this study will assist in future studies of UPEC strains to develop effective control measures.
Shigella spp. are enteric pathogens that cause shigellosis. We report here the high-quality whole-genome sequences of 59 historical Shigella strains that represent the four species and a variety of serotypes.
Oryza glaberrima is the African cultivated rice species, domesticated from its wild ancestor by farmers living in Inland Delta of Niger River. Several studies indicated that it has extremely narrow genetic diversity compared to both its wild progenitor, Oryza barthii and the Asian rice, Oryza sativa which can mainly be attributed to a severe domestication bottleneck. Despite its scarcity in farmer’s field due to its low yield potential, high shattering and lodging susceptibility, O. glaberrima is of great value not only to Africa but also globally. Perhaps its greatest contribution to regional and global food security is as a source of genes, as it possesses resistance/tolerance to various biotic and abiotic stresses. It also has unique starch-related traits which give it good cooking and eating properties. Advances in DNA sequencing have provided useful genomic resources for African rice, key among them being whole genome sequences. Genomic tools are enabling greater understanding of the useful functional diversity found in this species. These advances have potential of addressing some of the undesirable attributes found in this species which have led to its continued replacement by Asian rice. Development of new generation of rice varieties for African farmers will therefore require the adoption of advanced molecular breeding tools as these will allow efficient utilization of the wealth and resilience found in African rice in rice improvement.
The Alternaria genus consists of saprophytic fungi as well as plant-pathogenic species that have significant economic impact. To date, the genomes of multiple Alternaria species have been sequenced. These studies have yielded valuable data for molecular studies on Alternaria fungi. However, most of the current Alternaria genome assemblies are highly fragmented, thereby hampering the identification of genes that are involved in causing disease. Here, we report a gapless genome assembly of A. solani, the causal agent of early blight in tomato and potato. The genome assembly is a significant step toward a better understanding of pathogenicity of A. solani.
Paenibacillus donghaensis JH8T (KCTC 13049T=LMG 23780T) is a Gram-positive, mesophilic, endospore-forming bacterium isolated from East Sea sediment at depth of 500m in Korea. The strain exhibited plant cell wall hydrolytic and plant growth promoting abilities. The complete genome of P. donghaensis strain JH8T contains 7602 protein-coding sequences and an average GC content of 49.7% in its chromosome (8.54Mbp). Genes encoding proteins related to the degradation of plant cell wall, nitrogen-fixation, phosphate solubilization, and synthesis of siderophore were existed in the P. donghaensis strain JH8T genome, indicating that this strain can be used as an eco-friendly microbial agent for increasing agricultural productivity.
Contents Summary 45 I. Introduction 45 II. Targeted chromosome-based cloning via long-range assembly (TACCA) 46 III. Resistance gene cloning through mutational mapping (MutMap) 47 IV. Cloning through mutant chromosome sequencing (MutChromSeq) 47 V. Rapid cloning through resistance gene enrichment and sequencing (RenSeq) 49 VI. Cloning resistance genes through transcriptome profiling (RNAseq) 49 VII. Resistance gene deployment strategies 49 VIII. Conclusions 50 Acknowledgements 50 References 50 SUMMARY: Genetically encoded resistance is a major component of crop disease management. Historically, gene loci conferring resistance to pathogens have been identified through classical genetic methods. In recent years, accelerated gene cloning strategies have become available through advances in sequencing, gene capture and strategies for reducing genome complexity. Here, I describe these approaches with key emphasis on the isolation of resistance genes to the cereal crop diseases that are an ongoing threat to global food security. Rapid gene isolation enables their efficient deployment through marker-assisted selection and transgenic technology. Together with innovations in genome editing and progress in pathogen virulence studies, this creates further opportunities to engineer long-lasting resistance. These approaches will speed progress towards a future of farming using fewer pesticides.© 2017 Commonwealth of Australia. New Phytologist © 2017 New Phytologist Trust.
Ralstonia solanacearum is a soil-borne phytopathogen associated with bacterial wilt disease of sesame. R. solanacearum is the predominant agent causing damping-off from tropical to temperate regions. Because bacterial wilt has decreased the sesame industry yield, we sequenced the SEPPX05 genome using PacBio and Illumina HiSeq 2500 systems and revealed that R. solanacearum strain SEPPX05 carries a bipartite genome consisting of a 3,930,849 bp chromosome and a 2,066,085 bp megaplasmid with 66.84% G+C content that harbors 5,427 coding sequences. Based on the whole genome, phylogenetic analysis showed that strain SEPPX05 is grouped with two phylotype I strains (EP1 and GMI1000). Pan-genomic analysis shows that R. solanacearum is a complex species with high biological diversity and was able to colonize various environments during evolution. Despite deletions, insertions, and inversions, most genes of strain SEPPX05 have relatively high levels of synteny compared with strain GMI1000. We identified 104 genes involved in virulence-related factors in the SEPPX05 genome and eight absent genes encoding T3Es of GMI1000. Comparing SEPPX05 with other species, we found highly conserved secretion systems central to modulating interactions of host bacteria. These data may provide important clues for understanding underlying pathogenic mechanisms of R. solanacearum and help in the control of sesame bacterial wilt.
Sheep scab, caused by infestation with Psoroptes ovis, is highly contagious, results in intense pruritus, and represents a major welfare and economic concern. Here, we report the first draft genome assembly and gene prediction of P. ovis based on PacBio de novo sequencing. The ~63.2-Mb genome encodes 12,041 protein-coding genes. Copyright © 2018 Burgess et al.
Here, we report the complete genome sequence of multiple-antibiotic-resistant Streptococcus parauberis strain SPOF3K, isolated from the kidney of a diseased olive flounder in South Korea in 2013. Sequencing using a PacBio platform yielded a circular chromosome of 2,128,740?bp and a plasmid of 23,538?bp, harboring 2,123 and 24 protein-coding genes, respectively. Copyright © 2018 Lee et al.
Ganoderma boninense is the dominant fungal pathogen of basal stem rot (BSR) disease on Elaeis guineensis We sequenced the nuclear genome of mycelia using both Illumina and Pacific Biosciences platforms for assembly of scaffolds. The draft genome comprised 79.24?Mb, 495 scaffolds, and 26,226 predicted coding sequences. Copyright © 2018 Utomo et al.
A light pink coloured bacterial strain ERGS5:01 isolated from glacial stream water of Sikkim Himalaya was affiliated to Janthinobacterium lividum based on 16S rRNA gene sequence identity and phylogenetic clustering. Whole genome sequencing was performed for the strain to confirm its taxonomy as it lacked the typical violet pigmentation of the genus and also to decipher its survival strategy at the aquatic ecosystem of high elevation. The PacBio RSII sequencing generated genome of 5,168,928 bp with 4575 protein-coding genes and 118 RNA genes. Whole genome-based multilocus sequence analysis clustering, in silico DDH similarity value of 95.1% and, the ANI value of 99.25% established the identity of the strain ERGS5:01 (MCC 2953) as a non-violacein producing J. lividum. The genome comparisons across genus Janthinobacterium revealed an open pan-genome with the scope of the addition of new orthologous cluster to complete the genomic inventory. The genomic insight provided the genetic basis of freezing and frequent freeze-thaw cycle tolerance and, for industrially important enzymes. Extended insight into the genome provided clues of crucial genes associated with adaptation in the harsh aquatic ecosystem of high altitude.
Emerging single-molecule sequencing technologies from Pacific Biosciences and Oxford Nanopore have revived interest in long-read mapping algorithms. Alignment-based seed-and-extend methods demonstrate good accuracy, but face limited scalability, while faster alignment-free methods typically trade decreased precision for efficiency. In this article, we combine a fast approximate read mapping algorithm based on minimizers with a novel MinHash identity estimation technique to achieve both scalability and precision. In contrast to prior methods, we develop a mathematical framework that defines the types of mapping targets we uncover, establish probabilistic estimates of p-value and sensitivity, and demonstrate tolerance for alignment error rates up to 20%. With this framework, our algorithm automatically adapts to different minimum length and identity requirements and provides both positional and identity estimates for each mapping reported. For mapping human PacBio reads to the hg38 reference, our method is 290?×?faster than Burrows-Wheeler Aligner-MEM with a lower memory footprint and recall rate of 96%. We further demonstrate the scalability of our method by mapping noisy PacBio reads (each =5?kbp in length) to the complete NCBI RefSeq database containing 838 Gbp of sequence and >60,000 genomes.
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