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Asset Tag: Plant and Animal Sciences,

July 7, 2019  |  

The sequenced angiosperm genomes and genome databases.

Angiosperms, the flowering plants, provide the essential resources for human life, such as food, energy, oxygen, and materials. They also promoted the evolution of human, animals, and the planet earth. Despite the numerous advances in genome reports or sequencing technologies, no review covers all the released angiosperm genomes and the genome databases for data sharing. Based on the rapid advances and innovations in the database reconstruction in the last few years, here we provide a comprehensive review for three major types of angiosperm genome databases, including databases for a single species, for a specific angiosperm clade, and for multiple angiosperm species. The scope, tools, and data of each type of databases and their features are concisely discussed. The genome databases for a single species or a clade of species are especially popular for specific group of researchers, while a timely-updated comprehensive database is more powerful for address of major scientific mysteries at the genome scale. Considering the low coverage of flowering plants in any available database, we propose construction of a comprehensive database to facilitate large-scale comparative studies of angiosperm genomes and to promote the collaborative studies of important questions in plant biology.

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July 7, 2019  |  

Next-generation sequencing of Haematococcus lacustris reveals an extremely large 1.35-megabase chloroplast genome.

Haematococcus lacustris is an industrially relevant microalga that is used for the production of the carotenoid astaxanthin. Here, we report the use of PacBio long-read sequencing to assemble the chloroplast genome of H. lacustris strain UTEX:2505. At 1.35?Mb, this is the largest assembled chloroplast of any plant or alga known to date. Copyright © 2018 Bauman et al.

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July 7, 2019  |  

Draft genome sequence of Bacillus velezensis Lzh-a42, a plant growth- promoting rhizobacterium isolated from tomato rhizosphere.

The plant growth-promoting rhizobacterium Bacillus velezensis strain Lzh-a42, which has antimicrobial activity, was isolated from tomato rhizosphere. Here, we report its genome sequence, which includes several predicted functional genes related to secondary metabolite biosynthesis, antimicrobial activity, and biofilm synthesis. Copyright © 2018 Li et al.

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July 7, 2019  |  

Complete genome sequence of the symbiotic strain Bradyrhizobium icense LMTR 13T, isolated from lima bean (Phaseolus lunatus) in Peru.

The complete genome sequence of Bradyrhizobium icense LMTR 13T, a root nodule bacterium isolated from the legume Phaseolus lunatus, is reported here. The genome consists of a circular 8,322,773-bp chromosome which codes for a large and novel symbiotic island as well as genes putatively involved in soil and root colonization. Copyright © 2018 Ormeño-Orrillo et al.

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July 7, 2019  |  

Draft genome sequence and annotation of the phytopathogenic Ralstonia pickettii (previously Burkholderia glumae) strain ICMP-8657.

Strain ICMP-8657 was formerly taxonomically classified as Burkholderia glumae and reported to be the producer of an antibacterial pyrazole derivative. Here, we report the draft genome sequence of ICMP-8657, which failed to demonstrate the biosynthetic capacity to produce the stated antibacterial compound, leading to its taxonomic reclassification as Ralstonia pickettii ICMP-8657. Copyright © 2018 Paterson and Gross.

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July 7, 2019  |  

A draft genome sequence for the Ixodes scapularis cell line, ISE6

Background: The tick cell line ISE6, derived from Ixodes scapularis, is commonly used for amplification and detection of arboviruses in environmental or clinical samples. Methods: To assist with sequence-based assays, we sequenced the ISE6 genome with single-molecule, long-read technology. Results: The draft assembly appears near complete based on gene content analysis, though it appears to lack some instances of repeats in this highly repetitive genome. The assembly appears to have separated the haplotypes at many loci. DNA short read pairs, used for validation only, mapped to the cell line assembly at a higher rate than they mapped to the Ixodes scapularis reference genome sequence. Conclusions: The assembly could be useful for filtering host genome sequence from sequence data obtained from cells infected with pathogens.

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July 7, 2019  |  

Reconstruction of the repetitive antifreeze glycoprotein genomic loci in the cold-water gadids Boreogadus saida and Microgadus tomcod.

Antifreeze glycoproteins (AFGPs) are a novel evolutionary innovation in members of the northern cod fish family (Gadidae), crucial in preventing death from inoculative freezing by environmental ice in their frigid Arctic and sub-Arctic habitats. However, the genomic origin and molecular mechanism of evolution of this novel life-saving adaptive genetic trait remained to be definitively determined. To this end, we constructed large insert genomic DNA BAC (bacterial artificial chromosome) libraries for two AFGP-bearing gadids, the high-Arctic polar cod Boreogadus saida and the cold-temperate Atlantic tomcod Microgadus tomcod, to isolate and sequence their AFGP genomic regions for fine resolution evolutionary analyses. The BAC library construction encountered poor cloning efficiency initially, which we resolved by pretreating the agarose-embedded erythrocyte DNA with a cationic detergent, a method that may be of general use to BAC cloning for teleost species and/or where erythrocytes are the source of input DNA. The polar cod BAC library encompassed 92,160 clones with an average insert size of 94.7?kbp, and the Atlantic tomcod library contained 73,728 clones with an average insert size of 89.6?kbp. The genome sizes of B. saida and M. tomcod were estimated by cell flow cytometry to be 836?Mbp and 645?Mbp respectively, thus their BAC libraries have approximately 10- and 9.7-fold genome coverage respectively. The inclusiveness and depth of coverage were empirically confirmed by screening the libraries with three housekeeping genes. The BAC clones that mapped to the AFGP genomic loci of the two gadids were then isolated by screening the BAC libraries with gadid AFGP gene probes. Eight minimal tiling path (MTP) clones were identified for B. saida, sequenced, and assembled. The B. saida AFGP locus reconstruction produced both haplotypes, and the locus comprises three distinct AFGP gene clusters, containing a total of 16 AFGP genes and spanning a combined distance of 512?kbp. The M. tomcod AFGP locus is much smaller at approximately 80?kbp, and contains only three AFGP genes. Fluorescent in situ hybridization with an AFGP gene probe showed the AFGP locus in both species occupies a single chromosomal location. The large AFGP locus with its high gene dosage in B. saida is consistent with its chronically freezing high Arctic habitats, while the small gene family in M. tomcod correlates with its milder habitats in lower latitudes. The results from this study provided the data for fine resolution sequence analyses that would yield insight into the molecular mechanisms and history of gadid AFGP gene evolution driven by northern hemisphere glaciation. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

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July 7, 2019  |  

Genome sequence of Pseudomonas chlororaphis Lzh-T5, a plant growth-promoting rhizobacterium with antimicrobial activity.

Pseudomonas chlororaphis Lzh-T5 is a plant growth-promoting rhizobacterium (PGPR) with antimicrobial activity isolated from tomato rhizosphere in the city of Dezhou, Shandong Province, China. Here, the draft genome sequence of P. chlororaphis Lzh-T5 is reported, and several functional genes related to antifungal antibiotics and siderophore biosynthesis have been found in the genome. Copyright © 2018 Li et al.

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July 7, 2019  |  

Genome sequence of Bacillus cereus strain TG1-6, a plant-beneficial rhizobacterium that is highly salt tolerant.

The complete genome sequence of Bacillus cereus strain TG1-6, which is a highly salt-tolerant rhizobacterium that enhances plant tolerance to drought stress, is reported here. The sequencing process was performed based on a combination of pyrosequencing and single-molecule sequencing. The complete genome is estimated to be approximately 5.42?Mb, containing a total of 5,610 predicted protein-coding DNA sequences (CDSs). Copyright © 2018 Vílchez et al.

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July 7, 2019  |  

Complete genome sequence of Colwellia hornerae PAMC 20917, a cold-active enzyme-producing bacterium isolated from the Arctic Ocean sediment

Psychrophilic bacteria are considered a source of cold-active enzymes that can be used in industrial applications. The Arctic bacterium Colwellia hornerae PAMC 20917 strain has been isolated from the offshore sediment near Ny-Ålesund, Svalbard. The optimal growth temperature of the strain was 10?°C on marine agar. The cell lysate showed alkaline phosphatase activities. Analysis of the enzymatic properties showed that the alkaline phosphatase was cold-active and thermolabile. To explore useful cold-active industrial enzymes further, the entire genome of the PAMC 20917 strain was sequenced. The genome of the strain contained 4,684,314 nucleotides, with 37.87% G+C content. Genome mining analysis revealed that, in the complete genome sequence, three proteins were annotated as alkaline phosphatases. The genome of PAMC 20917 encodes cold shock proteins and an ice-binding protein that inhibits the growth of ice, allowing the bacterium to adapt to cold environments. This genome information may be useful for understanding mechanisms of adaptation to cold stress.

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July 7, 2019  |  

Identification of repetitive DNA sequences in the Chrysanthemum boreale genome

We previously revealed that the Chrysanthemum boreale genome is highly repetitive; however, the types and nucleotide sequences of repetitive DNA in this diploid wild chrysanthemum are not known. Here, we characterized repetitive DNA sequences in the C. boreale genome by analysing genomic sequences obtained by Illumina sequencing and confirmed their repetitive nature by conducting fluorescence in situ hybridization (FISH) analyses. Annotation of the obtained DNA sequences revealed that microsatellite-containing genomic sequences exhibited similarity with genomic sequences in Chrysanthemum morifolium, indicating sequence conservation of repetitive DNA sequences between the two Chrysanthemum species. Two superfamilies of repetitive DNA, Copia and Gypsy, belonging to the long-terminal repeat (LTR) class of retrotransposons, are abundant in the C. boreale genome. We propose that Copia and Gypsy retroelements contribute to the current genome architecture of C. boreale. Whole genome sequencing, which is currently in progress, will reveal the extent to which these repetitive DNA sequences contribute.

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July 7, 2019  |  

Identification of Pseudomonas mosselii BS011 gene clusters required for suppression of Rice Blast Fungus Magnaporthe oryzae.

Pseudomonas is a Gram-negative, rod-shaped bacteria. Many members of this genus displayed remarkable physiological and metabolic activity against different plant pathogens. However, Pseudomonas mosselii has not yet been characterized in biocontrol against plant disease. Here we isolated a strain of P. mosselii BS011 from the rhizosphere soil of rice plants, and the isolate showed strong inhibitory activity against the rice blast fungus Magnaporthe oryzae. Further we sequenced the complete genome of BS011, which consist of 5.75?Mb with a circular chromosome, 5,170 protein-coding genes, 23 rRNA and 78 tRNA operons. Bioinformatic analysis revealed that seven gene clusters may be involved in the biosynthesis of metabolites. Gene deletion experiments demonstrated that the gene cluster c-xtl is required for inhibitory activity against M. oryzae. Bioassay showed that the crude extract from BS011 fermentation sample significantly inhibited the development of M. oryzae at a concentration of 10?µg/ml. Besides, we illustrated that the crude extract of BS011 impaired the appressorial formation in a dose dependent manner. Collectively our results revealed that P. mosselii BS011 is a promising biocontrol agent and the gene cluster c-xtl is essential for inhibiting the development of M. oryzae. Copyright © 2018. Published by Elsevier B.V.

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