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Daejeon, South Korea

Hwang I.S.,Korea University | An S.H.,Dongbu Hannong Co. | Hwang B.K.,Korea University
Plant Journal | Year: 2011

Summary Asparagine synthetase is a key enzyme in the production of the nitrogen-rich amino acid asparagine, which is crucial to primary nitrogen metabolism. Despite its importance physiologically, the roles that asparagine synthetase plays during plant defense responses remain unknown. Here, we determined that pepper (Capsicum annuum) asparagine synthetase 1 (CaAS1) is essential for plant defense to microbial pathogens. Infection with Xanthomonas campestris pv. vesicatoria (Xcv) induced early and strong CaAS1 expression in pepper leaves and silencing of this gene resulted in enhanced susceptibility to Xcv infection. Transgenic Arabidopsis (Arabidopsis thaliana) plants that overexpressed CaAS1 exhibited enhanced resistance to Pseudomonas syringae pv. tomato DC3000 and Hyaloperonospora arabidopsidis. Increased CaAS1 expression influenced early defense responses in diseased leaves, including increased electrolyte leakage, reactive oxygen species and nitric oxide bursts. In plants, increased conversion of aspartate to asparagine appears to be associated with enhanced resistance to bacterial and oomycete pathogens. In CaAS1-silenced pepper and/or CaAS1-overexpressing Arabidopsis, CaAS1-dependent changes in asparagine levels correlated with increased susceptibility or defense responses to microbial pathogens, respectively. Linking transcriptional and targeted metabolite studies, our results suggest that CaAS1 is required for asparagine synthesis and disease resistance in plants. © 2011 Blackwell Publishing Ltd.

The flu is an acute respiratory infectious disease caused by the influenza virus. As an alternative to chemically synthesized antiviral agents, many plant extracts and purified substances have been tested and shown to have selective activities against the influenza virus. These plants are normally traditional medicinal herbs used in Asian, Eastern European, Northern American, and some South American countries and include Echinacea purpurea, Cistus incanus, Geranium sanguineum L., Glycyrrhiza uralensis F., Ephedrae herba, etc. Their bioactive compounds, such as flavonoids, phenolic compounds, tannins, or aromatic compounds, have been identified and their mechanisms of antiviral action and immune response during the pathogenesis of influenza infection have been characterized. In addition, several mechanisms of antiviral activity against influenza virus have been proposed based on a series of in vitro and in vivo studies: (1) inhibiting acidification of intracellular endosome compartments required for fusion of viral and cellular membranes, or reducing membrane fluidity, which would inhibit fusion of the viral membrane; (2) interfering with viral entry by reducing the receptor binding activity through, for example, binding to the virus surface, or interfering with virus adsorption, and thereby inhibiting hemagglutinin binding to cellular receptors; (3) inhibiting neuraminidase, therefore preventing both the release of virus from infected cells and the formation of viral aggregates after release from host cells; and (4) inhibiting viral replication at the initial stage of viral infection. It is also known that several medicinal plants alleviate flu-like symptoms by modulating local and systemic proinflammatory cytokines in the host rather than through direct effects on viral replication. Nevertheless, the proper immune responses and the mechanism of the inhibitory activities of medicinal herbs, plant extracts, or their bioactive compounds need to be studied in more detail. © 2012 Elsevier B.V.

Kim J.I.,Highland Agriculture Research Center | Kwon M.,Highland Agriculture Research Center | Kim G.-H.,Korea University | Kim S.Y.,Dongbu Hannong Co. | Lee S.H.,Seoul National University
Journal of Asia-Pacific Entomology | Year: 2015

The Aphis gossypii imidacloprid-resistant (IR) strain was about 3800-fold resistant to imidacloprid. Synergistic bioassays revealed that metabolic factors were not likely involved in resistance. An isogenic susceptible (IGS) strain was generated and used as references for RNA-seq, qrtPCR and 2DE. There were no noticeable differences between IGS and IR strains in either the transcriptome or proteome profiles, confirming that imidacloprid resistance is likely due to the target site insensitivity. The IR strain was determined to possess a point mutation resulting in an R81T substitution only in the nAChR beta 1 subunit, which had been also reported to be responsible for the reduced sensitivity to imidacloprid in M. persicae. An nAChR beta 1 subunit transcript variant in the N-terminal region was found and an additional point mutation, L80S was also detected along with the R81T mutation in IR strain, suggesting its potential role in resistance. Taken together, the R81T mutation in the nAChR beta 1 subunit, perhaps with the L80S mutation as well, could be the major factor of imidaloprid resistance in the IR strain and can be employed as molecular markers for the detection of imidacloprid resistance in field populations of A. gossypii. •We find new case in imidacloprid resistance mechanism in insect.•Mutations confer the resistance phenotype without P450-mediated detoxification.•The L80S mutation along with the R81T mutation in nAChR can be the main player to develop imidacloprid resistance. © 2015 .

Lee Y.-P.,Dongbu Hannong Co. | Cho Y.,Dongbu Hannong Co. | Kim S.,Chonnam National University
Theoretical and Applied Genetics | Year: 2014

Key message: We utilized a combination of BSA and RNA-Seq to identify SNPs linked to theRfd1locus, a restorer-of-fertility gene in radish. A high-density linkage map was constructed using this approach. Abstract: Male fertility of cytoplasmic male sterility conditioned by the Dongbu cytoplasmic and genic male-sterility cytoplasm can be restored by a restorer-of-fertility locus, Rfd1, in radish. To construct a high-density linkage map and to identify a candidate gene for the Rfd1 locus, bulked segregant analysis and RNA-seq approaches were combined. A total of 26 and 28 million reads produced from male-fertile and male-sterile bulked RNA were mapped to the radish reference unigenes. After stringent screening of SNPs, 327 reliable SNPs of 109 unigenes were selected. Arabidopsis homologs for 101 of the 109 genes were clustered around the 4,000 kb region of Arabidopsis chromosome 3, which was syntenic to the Rfd1 flanking region. Since the reference unigene set was incomplete, the contigs were de novo assembled to identify 134 contigs harboring SNPs. Most of SNP-containing contigs were also clustered on the same syntenic region in Arabidopsis chromosome. A total of 21 molecular markers positioned within a 2.1 cM interval including the Rfd1 locus were developed, based on the selected unigenes and contigs. A segregating population consisting of 10,459 individuals was analyzed to identify recombinants containing crossovers within this interval. A total of 284 identified recombinants were then used to construct a high-density map, which delimited the Rfd1 locus into an 83-kb syntenic interval of Arabidopsis chromosome 3. Since no candidate gene, such as a pentatricopeptide repeat (PPR)-coding gene, was found in this interval, 231 unigenes and 491 contigs containing putative PPR motifs were analyzed further, but no PPR gene in linkage disequilibrium with the Rfd1 locus could be found. © 2014, Springer-Verlag Berlin Heidelberg.

Kim D.,Chonnam National University | Jung J.,Dongbu Hannong Co. | Choi Y.-O.,Dongbu Hannong Co. | Kim S.,Chonnam National University
Euphytica | Year: 2016

To develop a reliable system for identifying multiple S haplotypes controlling self-incompatibility (SI) in radish (Raphanus sativus L.), the genomic organization of the S locus region was identified from radish draft genome sequences. An initial attempt to find the S receptor kinase (SRK) gene, the female determinant of SI, failed due to presence of 15 homologous genes. Using synteny between the radish and Chinese cabbage genomes, the putative S locus region was identified in the radish R7 linkage group. One scaffold anchored to this R7 region contained the S-locus glycoprotein (SLG) gene, which is one of the S locus genes. Using the high homology between the SLG and S domain of SRK, the full-length radish SRK gene containing the largest 6861-bp intron1 was assembled by connecting two scaffolds harboring the S receptor and kinase domains, respectively. A scaffold containing the full-length S-locus cysteine-rich protein (SCR)/S locus protein 11 (SP11) gene, the male-determinant of SI, was identified using information reported previously. Finally, 53,785, 42,804, and 10,165 bp sequences containing the S locus genes and their flanking sequences were obtained. Unlike the various orientations of the SRK or SCR/SP11 genes, the position of SLL2 located at the border region of the S locus was conserved among haplotypes. Sequencing of the SLL2 gene from 31 inbred lines showing differential SI responses revealed 26 polymorphic alleles. Four additional SLL2 alleles were identified from analysis of diverse breeding lines. Based on the polymorphic SLL2 sequences, a new S haplotyping system was developed for efficient marker-assisted selection of the S haplotypes in radish. © 2016 Springer Science+Business Media Dordrecht

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