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Seocheon, South Korea

Khan A.,Gyeongsang National University | Hossain M.T.,Gyeongsang National University | Park H.C.,National Institute of Ecology NIE | Yun D.-J.,Gyeongsang National University | And 2 more authors.
Plant and Soil | Year: 2016

Background and aims: Many rhizobacteria promote plant growth by producing hormones that stimulate the development of plant root system and increase plant biomass. The aim of this study was to investigate the growth promotion activity of the bacterial strain Martelella endophytica YC6887 and elucidate the signaling pathways potentially involved in Arabidopsis interaction with M. endophytica YC6887. Methods: The growth regulation was evaluated by inoculation of strain YC6887 with wild-type Arabidopsis Col-0 seedlings and mutants defective in auxin aux1-7, axr4-2, eir1-1, ethylene ein2-1, etr1-3, jasmonic acid signaling jar1, and root hair deficient mutant rhd6. The auxin response was further determined by using transgenic line DR5::GUS and a polar auxin transport inhibitor, 1-N-naphthylphthalamic acid (NPA). Results: M. endophytica YC6887 increased the number of lateral roots and plant biomass of Arabidopsis by producing phenylacetic acid. The growth promotion and improved lateral root development by the bacterium decreased in the auxin related mutants, whereas the ethylene and jasmonic acid mutants had a wild type response. The strain YC6887 increased root hair density in wild type Col-0 and recovered the root hair forming ability in root hair deficient mutant rhd6. Moreover, strain YC6887 treatment showed distinct response in DR5::GUS transgenic line compared to the control. Strain YC6887 lost its growth-promoting activity in the presence of NPA, an auxin transport inhibitor. This indicated that strain YC6887 activated the auxin signaling mechanism. Conclusions: Our results showed that M. endophytica YC6887 promoted plant growth in terms of plant biomass and root system development. Arabidopsis root system development upon M. endophytica YC6887 colonization was dependent on auxin signaling, but independent of ethylene and jasmonic acid signaling. © 2016 Springer International Publishing Switzerland Source

Ali A.,Gyeongsang National University | Raddatz N.,Technical University of Madrid | Aman R.,Gyeongsang National University | Kim S.,Gyeongsang National University | And 14 more authors.
Plant Physiology | Year: 2016

A crucial prerequisite for plant growth and survival is the maintenance of potassium uptake, especially when high sodium surrounds the root zone. The Arabidopsis HIGH-AFFINITY K+ TRANSPORTER1 (HKT1), and its homologs in other salt-sensitive dicots, contributes to salinity tolerance by removing Na+ from the transpiration stream. However, TsHKT1;2, one of three HKT1 copies in Thellungiella salsuginea, a halophytic Arabidopsis relative, acts as a K+transporter in the presence of Na+ in yeast (Saccharomyces cerevisiae). Amino-acid sequence comparisons indicated differences between TsHKT1;2 and most other published HKT1 sequences with respect to an Asp residue (D207) in the second pore-loop domain. Two additional T. salsuginea and most other HKT1 sequences contain Asn (N) in this position. Wild-type TsHKT1;2 and altered AtHKT1 (AtHKT1N-D) complemented K+-uptake deficiency of yeast cells. Mutanthkt1-1 plants complemented with both AtHKT1N-D and TsHKT1;2 showed higher tolerance to salt stress than lines complemented by the wild-type AtHKT1. Electrophysiological analysis in Xenopus laevis oocytes confirmed the functional properties of these transporters and the differential selectivity for Na+ and K+based on the N/D variance in the pore region. This change also dictated inward-rectification for Na+ transport. Thus, the introduction of Asp, replacing Asn, in HKT1-type transporters established altered cation selectivity and uptake dynamics. We describe one way, based on a single change in a crucial protein that enabled some crucifer species to acquire improved salt tolerance, which over evolutionary time may have resulted in further changes that ultimately facilitated colonization of saline habitats. © 2016 American Society of Plant Biologists. All rights reserved. Source

Jo B.-H.,National Institute of Ecology NIE | Lee C.S.,Korea Research Institute of Bioscience and Biotechnology | Song H.-R.,National Institute of Ecology NIE | Lee H.-G.,Korea Research Institute of Bioscience and Biotechnology | Oh H.-M.,Korea Research Institute of Bioscience and Biotechnology
Journal of Microbiology and Biotechnology | Year: 2014

A strain-specific identification method is required to secure Chlorella strains with useful genetic traits, such as a fast growth rate or high lipid productivity, for application in biofuels, functional foods, and pharmaceuticals. Microsatellite markers based on simple sequence repeats can be a useful tool for this purpose. Therefore, this study developed five novel microsatellite markers (mChl-001, mChl-002, mChl-005, mChl-011, and mChl-012) using specific loci along the chloroplast genome of Chlorella vulgaris. The microsatellite markers were characterized based on their allelic diversities among nine strains of C. vulgaris with the same 18S rRNA sequence similarity. Each microsatellite marker exhibited 2∼5 polymorphic allele types, and their combinations allowed discrimination between seven of the C. vulgaris strains. The two remaining strains were distinguished using one specific interspace region between the mChl-001 and mChl-005 loci, which was composed of about 27 single nucleotide polymorphisms, 13∼15 specific sequence sites, and (T)n repeat sites. Thus, the polymorphic combination of the five microsatellite markers and one specific locus facilitated a clear distinction of C. vulgaris at the strain level, suggesting that the proposed microsatellite marker system can be useful for the accurate identification and classification of C. vulgaris. © 2014 by The Korean Society for Microbiology and Biotechnology. Source

Jo B.-H.,National Institute of Ecology NIE | Lee J.R.,National Institute of Ecology NIE | Choi W.,National Institute of Ecology NIE | Moon J.C.,National Institute of Ecology NIE | And 5 more authors.
Journal of Plant Biotechnology | Year: 2015

Canola is a crop globally used for production of oil and biofuel. Cultivation area and import volume of living modified (LM) canola have been increasing every year. As canola import dependence has reached 100% in Korea, efforts have been made for safety management of LM canola and ecological risk assessment. We developed a set of multiplex PCR method for simultaneous detection of 5 LM canola events (Topas 19/2, Rf3, Ms8, RT73 and T45) approved in Korea. The multiplex PCR assay developed allows amplification of estimated products of 5 LM canolas from event specific primer sets. Primer extension time was skipped for a time-consuming process and two annealing steps (20 cycles at 55°C and 20 cycles at 60°C) were performed for yielding the best result which was sufficient to distinguish five LM canolas. Our results suggest that multiplex PCR method provides a cost and time-effective approach for LM canola detection. © Korean Society for Plant Biotechnology. Source

Seol M.-A.,National Institute of Ecology NIE | Lee J.R.,National Institute of Ecology NIE | Choi W.,National Institute of Ecology NIE | Jo B.-H.,National Institute of Ecology NIE | And 5 more authors.
Journal of Plant Biotechnology | Year: 2015

Living modified organisms (LMO) are one of the most widespread products of modern biotechnology after DNA discovery. Due to the decline of grain selfsufficiency rate and the increase of reliance on LMO imports in Korea, a series of concerns with regard to safety of living modified(LM) crops has been raised. The aim of this study is to establish the detection methods for unintentional release or growing of LMO plants in environmental conditions. To detect LM crop events, general concepts of specific primer design and PCR conditions were provided by the Joint Research Centre (JRC). The certified reference materials of seven LM events (4 soybean, 2 cotton and 1 corn) were obtained from the Institute for Reference Materials and Measurements (IRMM) and the American Oil Chemists' Society (AOCS). Genomic DNA from seven LM events were purified and PCR amplifications were carried out by using individual event-specific primer sets. LM-specific PCR products of all seven events were efficiently amplified by our methods. The results indicate that the established detection method for LMOs is suitable as a scientific tool to monitor whether the crops found in natural environments are LMOs. © Korean Society for Plant Biotechnology. Source

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