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July 7, 2019  |  

Complete genome sequence of Kibdelosporangium phytohabitans KLBMP 1111(T), a plant growth promoting endophytic actinomycete isolated from oil-seed plant Jatropha curcas L.

Kibdelosporangium phytohabitans KLBMP 1111(T) is a plant growth promoting endophytic actinomycete isolated from the oil-seed plant Jatropha curcas L. collected from dry-hot valley, in Sichuan, China. The complete genome sequence of this actinomycete consists of one chromosome (11,759,770bp) with no plasmid. From the genome, we identified gene clusters responsible for polyketide and nonribosomal peptide synthesis of natural products, and genes related to the plant growth promoting, such as zeatin, 1-aminocyclopropane-1-carboxylate deaminase (ACCD) and siderophore. The complete genome information may be useful to understand the beneficial interactions between K. phytohabitans KLBMP 1111(T) and host plants. Copyright © 2015. Published by Elsevier B.V.


July 7, 2019  |  

Complete genome sequence of Pseudomonas aeruginosa PA1, isolated from a patient with a respiratory tract infection.

We report the 6,498,072-bp complete genome sequence of Pseudomonas aeruginosa PA1, which was isolated from a patient with a respiratory tract infection in Chongqing, People’s Republic of China. Whole-genome sequencing was performed using single-molecule real-time (SMRT) technology, and de novo assembly revealed a single contig with 396-fold sequence coverage. Copyright © 2015 Lu et al.


July 7, 2019  |  

Global insights into acetic acid resistance mechanisms and genetic stability of Acetobacter pasteurianus strains by comparative genomics.

Acetobacter pasteurianus (Ap) CICC 20001 and CGMCC 1.41 are two acetic acid bacteria strains that, because of their strong abilities to produce and tolerate high concentrations of acetic acid, have been widely used to brew vinegar in China. To globally understand the fermentation characteristics, acid-tolerant mechanisms and genetic stabilities, their genomes were sequenced. Genomic comparisons with 9 other sequenced Ap strains revealed that their chromosomes were evolutionarily conserved, whereas the plasmids were unique compared with other Ap strains. Analysis of the acid-tolerant metabolic pathway at the genomic level indicated that the metabolism of some amino acids and the known mechanisms of acetic acid tolerance, might collaboratively contribute to acetic acid resistance in Ap strains. The balance of instability factors and stability factors in the genomes of Ap CICC 20001 and CGMCC 1.41 strains might be the basis for their genetic stability, consistent with their stable industrial performances. These observations provide important insights into the acid resistance mechanism and the genetic stability of Ap strains and lay a foundation for future genetic manipulation and engineering of these two strains.


July 7, 2019  |  

Leafy spurge genomics: A model perennial weed to investigate development, stress responses, and invasiveness

Leafy spurge is wild flower native to Europe that has become an invasive perennial weed in the northern great plains of the USA and Canada. Leafy spurge primarily infests range and recreation lands and costs US land managers millions dollars annually. In its invaded range, leafy spurge can form vast monocultures that significantly impact native flora and fauna and has been attributed to reduced populations of endangered species such as the prairie fringed orchid. Leafy spurge has remarkable plasticity and can persist under environmental extremes—primarily due to the formation of hundreds of underground adventitious buds that can form on its extensive and deep root system. We have developed genomics-based tools to assist our investigations related to vegetative production from these underground buds, as well as its responses to stress, and the potential mechanisms leading to the invasiveness of leafy spurge. Towards these ends, we have utilized Sanger-based sequencing to develop EST-databases from leafy spurge and cassava (a related species) transcriptomes, and developed textasciitilde23,000 element cDNA microarrays representing all of the unigenes identified in these databases. Additionally, numerous cDNA libraries and genomic libraries have been developed including bacterial artificial chromosome libraries useful for identifying and characterizing promoters of differentially expressed genes. Finally, to enhance our ability to identify promoter sequences and transcription factors involved in vegetative production, stress responses, and invasiveness, we have incorporated next generation sequencing approaches to fully sequence the leafy spurge genome. Using global transcriptome profiles, next generation sequencing, bioinformatics programs has provided insights into molecular mechanisms and regulatory pathways that make leafy spurge a particularly invasive and difficult weed to control.


July 7, 2019  |  

Complete sequences of organelle genomes from the medicinal plant Rhazya stricta (Apocynaceae) and contrasting patterns of mitochondrial genome evolution across asterids.

Rhazya stricta is native to arid regions in South Asia and the Middle East and is used extensively in folk medicine to treat a wide range of diseases. In addition to generating genomic resources for this medicinally important plant, analyses of the complete plastid and mitochondrial genomes and a nuclear transcriptome from Rhazya provide insights into inter-compartmental transfers between genomes and the patterns of evolution among eight asterid mitochondrial genomes.The 154,841 bp plastid genome is highly conserved with gene content and order identical to the ancestral organization of angiosperms. The 548,608 bp mitochondrial genome exhibits a number of phenomena including the presence of recombinogenic repeats that generate a multipartite organization, transferred DNA from the plastid and nuclear genomes, and bidirectional DNA transfers between the mitochondrion and the nucleus. The mitochondrial genes sdh3 and rps14 have been transferred to the nucleus and have acquired targeting presequences. In the case of rps14, two copies are present in the nucleus; only one has a mitochondrial targeting presequence and may be functional. Phylogenetic analyses of both nuclear and mitochondrial copies of rps14 across angiosperms suggests Rhazya has experienced a single transfer of this gene to the nucleus, followed by a duplication event. Furthermore, the phylogenetic distribution of gene losses and the high level of sequence divergence in targeting presequences suggest multiple, independent transfers of both sdh3 and rps14 across asterids. Comparative analyses of mitochondrial genomes of eight sequenced asterids indicates a complicated evolutionary history in this large angiosperm clade with considerable diversity in genome organization and size, repeat, gene and intron content, and amount of foreign DNA from the plastid and nuclear genomes.Organelle genomes of Rhazya stricta provide valuable information for improving the understanding of mitochondrial genome evolution among angiosperms. The genomic data have enabled a rigorous examination of the gene transfer events. Rhazya is unique among the eight sequenced asterids in the types of events that have shaped the evolution of its mitochondrial genome. Furthermore, the organelle genomes of R. stricta provide valuable genomic resources for utilizing this important medicinal plant in biotechnology applications.


July 7, 2019  |  

Draft genome assembly and annotation of Glycyrrhiza uralensis, a medicinal legume.

Chinese liquorice/licorice (Glycyrrhiza uralensis) is a leguminous plant species whose roots and rhizomes have been widely used as a herbal medicine and natural sweetener. Whole-genome sequencing is essential for gene discovery studies and molecular breeding in liquorice. Here, we report a draft assembly of the approximately 379-Mb whole-genome sequence of strain 308-19 of G. uralensis; this assembly contains 34 445 predicted protein-coding genes. Comparative analyses suggested well-conserved genomic components and collinearity of gene loci (synteny) between the genome of liquorice and those of other legumes such as Medicago and chickpea. We observed that three genes involved in isoflavonoid biosynthesis, namely, 2-hydroxyisoflavanone synthase (CYP93C), 2,7,4′-trihydroxyisoflavanone 4′-O-methyltransferase/isoflavone 4′-O-methyltransferase (HI4OMT) and isoflavone-7-O-methyltransferase (7-IOMT) formed a cluster on the scaffold of the liquorice genome and showed conserved microsynteny with Medicago and chickpea. Based on the liquorice genome annotation, we predicted genes in the P450 and UDP-dependent glycosyltransferase (UGT) superfamilies, some of which are involved in triterpenoid saponin biosynthesis, and characterised their gene expression with the reference genome sequence. The genome sequencing and its annotations provide an essential resource for liquorice improvement through molecular breeding and the discovery of useful genes for engineering bioactive components through synthetic biology approaches.© 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.


July 7, 2019  |  

Identification of symmetrical RNA editing events in the mitochondria of Salvia miltiorrhiza by strand-specific RNA sequencing.

Salvia miltiorrhiza is one of the most widely-used medicinal plants. Here, we systematically analyzed the RNA editing events in its mitochondria. We developed a pipeline using REDItools to predict RNA editing events from stand-specific RNA-Seq data. The predictions were validated using reverse transcription, RT-PCR amplification and Sanger sequencing experiments. Putative sequences motifs were characterized. Comparative analyses were carried out between S. miltiorrhiza, Arabidopsis thaliana and Oryza sativa. We discovered 1123 editing sites, including 225 “C to U” sites in the protein-coding regions. Fourteen of sixteen (87.5%) sites were validated. Three putative DNA motifs were identified around the predicted sites. The nucleotides on both strands at 115 of the 225 sites had undergone RNA editing, which we called symmetrical RNA editing (SRE). Four of six these SRE sites (66.7%) were experimentally confirmed. Re-examination of strand-specific RNA-Seq data from A. thaliana and O. sativa identified 327 and 369 SRE sites respectively. 78, 20 and 13 SRE sites were found to be conserved among A. thaliana, O. sativa and S. miltiorrhiza respectively. This study provides a comprehensive picture of RNA editing events in the mitochondrial genome of S. miltiorrhiza. We identified SREs for the first time, which may represent a universal phenomenon.


July 7, 2019  |  

Plant growth-promoting effect and genomic analysis of the beneficial endophyte Streptomyces sp. KLBMP 5084 isolated from halophyte Limonium sinense

Background and aims: Soil salinity is a worldwide environmental problem that can hinder plant development and therefore negatively impact crop production. Inoculation of halophytic plants with plant growth-promoting (PGP) actinobacteria has been suggested as one strategy to improve salt tolerance. Here we performed a glasshouse experiment to test the effect of a PGP halotolerant endophytic actinomycete strain, KLBMP 5084 on the performance of the halophyte Limonium sinense under conditions of salt stress. Methods: Strain KLBMP 5084 was identified and screened for multiple PGP traits. The complete genome of strain KLBMP 5084 was sequenced and analyzed. L. sinense control seedlings (no inoculation) and seedlings inoculated with KLBMP 5084 were given different NaCl (0, 100 and 250 mM) salt-stress treatments. Growth parameters and physiological responses of L. sinense were determined after harvest. Results: Compared with the control, plants inoculated with strain KLBMP 5084 had greater in fresh weight, root length, leaf length and total chlorophyll and proline contents under both normal and high salinity conditions. Compared with control, inoculated plants had significantly lower leaf malondialdehyde (MDA) content and significantly more antioxidant enzymes. Moreover, inoculated plants had significantly lower accumulation of Na+ in both leaves and roots under high salt-stress conditions. Genomic analysis of strain KLBMP 5084 revealed many PGP related genes, including some genes putatively involved in salt tolerance and harsh environment adaptation. Conclusion: Strain KLBMP 5084 seems to confer salt tolerance to host plant L. sinense through more than one mechanism, suggesting KLBMP 5084 could be a strong PGP agent to improve plant yields and tolerance to salinity stress.


July 7, 2019  |  

Gene losses and partial deletion of small single-copy regions of the chloroplast genomes of two hemiparasitic Taxillus species.

Numerous variations are known to occur in the chloroplast genomes of parasitic plants. We determined the complete chloroplast genome sequences of two hemiparasitic species, Taxillus chinensis and T. sutchuenensis, using Illumina and PacBio sequencing technologies. These species are the first members of the family Loranthaceae to be sequenced. The complete chloroplast genomes of T. chinensis and T. sutchuenensis comprise circular 121,363 and 122,562 bp-long molecules with quadripartite structures, respectively. Compared with the chloroplast genomes of Nicotiana tabacum and Osyris alba, all ndh genes as well as three ribosomal protein genes, seven tRNA genes, four ycf genes, and the infA gene of these two species have been lost. The results of the maximum likelihood and neighbor-joining phylogenetic trees strongly support the theory that Loranthaceae and Viscaceae are monophyletic clades. This research reveals the effect of a parasitic lifestyle on the chloroplast structure and genome content of T. chinensis and T. sutchuenensis, and enhances our understanding of the discrepancies in terms of assembly results between Illumina and PacBio.


July 7, 2019  |  

The Tartary buckwheat genome provides insights into rutin biosynthesis and abiotic stress tolerance.

Tartary buckwheat (Fagopyrum tataricum) is an important pseudocereal crop that is strongly adapted to growth in adverse environments. Its gluten-free grain contains complete proteins with a well-balanced composition of essential amino acids and is a rich source of beneficial phytochemicals that provide significant health benefits. Here, we report a high-quality, chromosome-scale Tartary buckwheat genome sequence of 489.3 Mb that is assembled by combining whole-genome shotgun sequencing of both Illumina short reads and single-molecule real-time long reads, sequence tags of a large DNA insert fosmid library, Hi-C sequencing data, and BioNano genome maps. We annotated 33 366 high-confidence protein-coding genes based on expression evidence. Comparisons of the intra-genome with the sugar beet genome revealed an independent whole-genome duplication that occurred in the buckwheat lineage after they diverged from the common ancestor, which was not shared with rosids or asterids. The reference genome facilitated the identification of many new genes predicted to be involved in rutin biosynthesis and regulation, aluminum stress resistance, and in drought and cold stress responses. Our data suggest that Tartary buckwheat’s ability to tolerate high levels of abiotic stress is attributed to the expansion of several gene families involved in signal transduction, gene regulation, and membrane transport. The availability of these genomic resources will facilitate the discovery of agronomically and nutritionally important genes and genetic improvement of Tartary buckwheat. Copyright © 2017 The Author. Published by Elsevier Inc. All rights reserved.


July 7, 2019  |  

Complete genome sequence of endophyte Bacillus flexus KLBMP 4941 reveals its plant growth promotion mechanism and genetic basis for salt tolerance.

Bacillus flexus KLBMP 4941 is a halotolerant endophyte isolated from the halophyte Limonium sinense. This strain can improve host seedling growth under salt stress conditions. We here report the complete genome information of endophyte KLBMP 4941. It has a circular chromosome and two plasmids for a total genome 4,104,242 bp in size with a G+C content of 38.09%. Genes related to plant growth promotion (PGP), such as those associated with nitrogen fixation, siderophore, spermidine, and acetoin synthesis were found in the KLBMP 4941 genome. Some genes responsible for high salinity tolerance, like genes associated with the Na(+)/H(+) antiporter, glycine betaine transporter, and betaine-aldehyde dehydrogenase were also found in the KLBMP 4941 genome. The genome analysis will provide better understanding of the mechanisms underlying the promotion of plant growth in strain KLBMP 4941 under salt stress conditions and its ability to adapt to coastal salt marsh habitats, and provide a basis for its further biotechnological applications in agriculture. Copyright © 2017 Elsevier B.V. All rights reserved.


July 7, 2019  |  

Post genomics era for orchid research.

Among 300,000 species in angiosperms, Orchidaceae containing 30,000 species is one of the largest families. Almost every habitats on earth have orchid plants successfully colonized, and it indicates that orchids are among the plants with significant ecological and evolutionary importance. So far, four orchid genomes have been sequenced, including Phalaenopsis equestris, Dendrobium catenatum, Dendrobium officinale, and Apostaceae shengen. Here, we review the current progress and the direction of orchid research in the post genomics era. These include the orchid genome evolution, genome mapping (genome-wide association analysis, genetic map, physical map), comparative genomics (especially receptor-like kinase and terpene synthase), secondary metabolomics, and genome editing.


July 7, 2019  |  

Complete chloroplast genome sequence of Fritillaria unibracteata var. wabuensis based on SMRT Sequencing Technology.

Fritillaria unibracteata var. wabuensis is an important medicinal plant used for the treatment of cough symptoms related to the respiratory system. The chloroplast genome of F. unibracteata var. wabuensis (GenBank accession no. KF769142) was assembled using the PacBio RS platform (Pacific Biosciences, Beverly, MA) as a circle sequence with 151 009?bp. The assembled genome contains 133 genes, including 88 protein-coding, 37 tRNA, and eight rRNA genes. This genome sequence will provide important resource for further studies on the evolution of Fritillaria genus and molecular identification of Fritillaria herbs and their adulterants. This work suggests that PacBio RS is a powerful tool to sequence and assemble chloroplast genomes.


July 7, 2019  |  

The complete chloroplast genome of Gentiana straminea (Gentianaceae), an endemic species to the Sino-Himalayan subregion.

Endemic to the Sino-Himalayan subregion, the medicinal alpine plant Gentiana straminea is a threatened species. The genetic and molecular data about it is deficient. Here we report the complete chloroplast (cp) genome sequence of G. straminea, as the first sequenced member of the family Gentianaceae. The cp genome is 148,991bp in length, including a large single copy (LSC) region of 81,240bp, a small single copy (SSC) region of 17,085bp and a pair of inverted repeats (IRs) of 25,333bp. It contains 112 unique genes, including 78 protein-coding genes, 30 tRNAs and 4 rRNAs. The rps16 gene lacks exon2 between trnK-UUU and trnQ-UUG, which is the first rps16 pseudogene found in the nonparasitic plants of Asterids clade. Sequence analysis revealed the presence of 13 forward repeats, 13 palindrome repeats and 39 simple sequence repeats (SSRs). An entire cp genome comparison study of G. straminea and four other species in Gentianales was carried out. Phylogenetic analyses using maximum likelihood (ML) and maximum parsimony (MP) were performed based on 69 protein-coding genes from 36 species of Asterids. The results strongly supported the position of Gentianaceae as one member of the order Gentianales. The complete chloroplast genome sequence will provide intragenic information for its conservation and contribute to research on the genetic and phylogenetic analyses of Gentianales and Asterids. Copyright © 2015 Elsevier B.V. All rights reserved.


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