• Journal of Plant Biotechnology
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• v.35 no.3
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• pp.185-193
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• 2008

We evaluated the response to salt stress of two different ginseng lines, STG3134 and STG3159, which are sensitive and tolerant, respectively, to salt treatment. Plants were exposed to a 5 dS/m salt solution, and chlorophyll fluorescence was measured. STG3134 ginseng was more sensitive than STG3159 to salt stress. To characterize the cellular response to salt stress in the two different lines, changes in protein expression were investigated using a proteomic approach. Total protein was extracted from detached salt-treated leaves of STG3134 and STG3159 ginseng, and then separated by two-dimensional polyacrylamide gel electrophoresis(2-DE). Approximately 468 protein spots were detected by 2-DE and Coommassie brilliant blue staining. Twenty-two proteins were found to be reproducibly up- or down-regulated in response to salt stress. Among these proteins, twelve were identified using MALDI-TOF MS and ESI-Q-TOF and classified into several functional groups: photosynthesis-related proteins(oxygen-evolving enhancer proteins 1 and 2, rubisco and rubisco activase), detoxification proteins(polyphenol oxidase) and defense proteins($\beta$-1,3-glucanase, ribonuclease-like storage protein, and isoflavone reductase-like protein). The protein levels of ribonuclease-like storage protein, which was highly induced in STG3159 ginseng as compared to STG3134, correlated tightly with mRNA transcript levels, as assessed by reverse-transcription(RT)-PCR. Our results indicate that salinity induces changes in the expression levels of specific proteins in the leaves of ginseng plants. These changes may, in turn, playa role in plant adaptation to saline conditions.

• Proceedings of the Korean Society of Crop Science Conference
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• 2023.04a
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• pp.32-32
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• 2023

Cadmium and salt exposure to crops is considered vulnerable for production as well as consumption. To address these challenges, the current study aimed to mitigate the toxicity induced by salt and cadmium in soybean plants through the application of bacterial strain Bacillus safensis KJW143 isolated from the rhizosphere of oriental melon..The bioassay analysis revealed that KJW143 is a highly salt-tolerant and cadmium-resistant (Cd) strain with an innate ability to produce melatonin, gibberellin (GA3), Indole-3-Acetic Acid (IAA), and organic acids (i.e., acetic, succinic, lactic, and propionic acids). Soybean plants at 20 days old were treated with KJW143 in a different form (pellet, broth, and together) and their effect on plant performance was investigated. Inoculation with KJW143enhanced plant biomass and growth attributes in soybean plants compared to the control (non-treated). In particular, we observed that only pellet-treated showed 65%, 27.5%, and 28.7% increase in growth (shoot fresh weight) compared to broth, broth with pellet, and control. In addition, bacterial strain KJW143 treatment (only pellet) modulated the physiochemical apparatus of soybean plants by increasing glucose (390%), arabinose (166%), citric acid (22.98%) and reducing hydrogen peroxide (29.7%), catalase (32.1%), salicylic acid (25.6%) compared to plants with combined stressed plants (cd and salinity). These findings suggest that bacterial strain KJW143 could be usedas a biofertilizer to minimize the probable risk of heavy metal and salinity stress on crops.

• Korean Journal of Breeding Science
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• v.42 no.5
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• pp.540-546
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• 2010

This study was conducted to understand the role of soybean pathogenesis-related 10 (GmPR10) gene in salt tolerance and to develop salt-tolerant rice using GmPR10 cDNA. GmPR10 transgene was expressed constitutively in the shoot and root of the $T_1$ transgenic rice plants. Interestingly, however, the levels of the transgene expression were increased temporally up to over four- to five-fold in the shoot and root by 125 mM NaCl treatment, peaking at six hours after the treatment and decreasing thereafter. Electrolyte leakage of leaf cells under 125 mM NaCl treatment was lower in all the transgenic lines than in the control variety, Dongjin-byeo. Ability of seedlings to recover from 125 mM NaCl treatment for two weeks was higher in the transgenic plants than in the control plants. These results demonstrated that GmPR10 had function to increase cell integrity and promote growth under the saline stress imposed by NaCl. The transgenic line GmPR10-3 which showed highest ability to recover from the saline stress could be used as a potential source for salt tolerance in rice breeding programs.

• Journal of Microbiology and Biotechnology
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• v.30 no.11
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• pp.1680-1687
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• 2020

Fungal endophytes are symbiotic microorganisms that are often found in asymptomatic plants. This study describes the genetic diversity of the fungal endophytes isolated from the roots of plants sampled from the west coast of Korea. Five halophytic plant species, Limonium tetragonum, Suaeda australis, Suaeda maritima, Suaeda glauca Bunge, and Phragmites australis, were collected from a salt marsh in Gochang and used to isolate and identify culturable, root-associated endophytic fungi. The fungal internal transcribed spacer (ITS) region ITS1-5.8S-ITS2 was used as the DNA barcode for the classification of these specimens. In total, 156 isolates of the fungal strains were identified and categorized into 23 genera and two phyla (Ascomycota and Basidiomycota), with Dothideomycetes and Sordariomycetes as the predominant classes. The genus Alternaria accounted for the largest number of strains, followed by Cladosporium and Fusarium. The highest diversity index was obtained from the endophytic fungal group associated with the plant P. australis. Waito-C rice seedlings were treated with the fungal culture filtrates to analyze their plant growth-promoting capacity. A bioassay of the Sm-3-7-5 fungal strain isolated from S. maritima confirmed that it had the highest plant growth-promoting capacity. Molecular identification of the Sm-3-7-5 strain revealed that it belongs to Alternaria alternata and is a producer of gibberellins. These findings provided a fundamental basis for understanding the symbiotic interactions between plants and fungi.

• Horticultural Science & Technology
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• v.31 no.6
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• pp.748-755
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• 2013

This study was conducted to find a salt tolerance gene in Brassica rapa. In order to meet this objective, we analyzed data from a KBGP-24K oligo chip [BrEMD (Brassica rapa EST and microarray database)] of the B. rapa ssp. pekinensis 'Chiifu' under salt stress (250 mM NaCl). From the B. rapa KBGP-24K microarray chip analysis, 202 salt-responsive unigenes were primarily selected under salt stress. Of these, a gene with unknown function but known full-length sequence was chosen to closely investigate the gene function. The selected gene was named BrSSR (B. rapa salt stress resistance). BrSSR contains a 285 bp open reading frame encoding a putative 94-amino acid protein, and a DUF581 domain. The pSL94 vector was designed to over-express BrSSR, and was used to transform tobacco plants for salt tolerance analysis. T1 transgenic tobacco plants that over-expressed BrSSR were selected by PCR and DNA blot analyses. Quantitative real-time RT PCR revealed that the expression of BrSSR in transgenic tobacco plants increased by approximately 3.8-fold. Similar results were obtained by RNA blot analysis. Phenotypic characteristics analysis showed that transgenic tobacco plants with over-expressed BrSSR were more salt-tolerant than the wild type control under 250 mM NaCl for 5 days. Based on these results, we hypothesized that the over-expression of BrSSR may be closely related to the enhancement of salt tolerance.

• Journal of Plant Biotechnology
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• v.41 no.2
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• pp.81-88
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• 2014

Salt cress (Thellungiella halophila or Thellungiella parvula), species closely related to Arabidopsis thaliana, represents an extremophile adapted to harsh saline environments. To isolate salt-tolerance genes from this species, we constructed a cDNA library from roots and leaves of salt cress plants treated with 200 mM NaCl. This cDNA library was subsequently shuttled into the destination binary vector [driven by the cauliflower mosaic virus (CaMV) 35S promoter] designed for plant transformation and expression via recombination- assisted cloning. In total, 305,400 pools of transgenic BASTA-resistant lines were generated in Arabidopsis using either T. halophila or T. parvula cDNA libraries. These were used for functional screening of genes involved in salt tolerance. Among these pools, 168,500 pools were used for primary screening to date from which 7,157 lines showed apparent salt tolerant-phenotypes in the initial screen. A secondary screen has now identified 165 salt tolerant transgenic lines using 1,551 (10.6%) lines that emerged in the first screen. The prevalent phenotype in these lines includes accelerated seed germination often accompanied by faster root growth compared to WT Arabidopsis under salt stress condition. In addition, other lines showed non-typical development of stems and flowers compared to WT Arabidopsis. Based on the close relationship of the tolerant species to the target species we suggest this approach as an appropriate method for the large-scale identification of salt tolerance genes from salt cress.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.237-237
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• 2017

Rice is highly sensitive to salt stress especially in its early growth stage, which thus is one of the major constraints in rice production. In rice plants, salt sensitivity is associated with the accumulation of $Na^+$ in the shoots, especially in the photosynthetic tissues. High salt concentrations in soil cause high $Na^+$ and $Cl^-$ transport to the shoot and preferential accumulation of those ions in older leaves, which decreases $K^+$ in the shoot, photosynthetic activity and grain yield. Salt exclusion capacity at the leaf sheath is therefore considered to be one of the main mechanisms of salt tolerance. In addition, it is suspected that the lamina joint might be involved in the salt transport from leaf sheath to leaf blade. This research aims to determine if leaf sheaths of rice exclude a large amount of $Na^+$ only or other ions such as $K^+$, $Ca^{2+}$, $Mg^{2+}$, and $Cl^-$ as well, to identify tissues in the leaf sheath, which accumulate $Na^+$, and to examine if the lamina joint is involved in the salt exclusion by the leaf sheath. The rice seedlings of salt tolerant genotype FL478 and salt sensitive genotype IR29 were independently treated with NaCl, KCl, $MgCl_2$ and $CaCl_2$, and Taichung 65 and its near-isogenic liguleless line (T65lg) were treated with NaCl. Then, the content of $Na^+$, $K^+$, $Ca^{2+}$, $Mg^{2+}$, and $Cl^-$ ions and their specific location were determined using Atomic Absorption Spectrometer, Ion Chromatograph, and Energy Dispersive X-ray Spectroscopy. Results showed that leaf sheaths of FL478 and IR29 accumulated a large amount of $Na^+$, $K^+$, $Ca^{2+}$, $Mg^{2+}$, and $Cl^-$ ons, and thus excluded them from leaf blades when treated with high concentration of each salt. When treated with NaCl, the highest $Na^+$ concentration was found in the basal part of leaf sheaths of both cultivars. Moreover, energy-dispersive X-ray spectroscopy revealed that the central parenchyma cells of the leaf sheath were the site where most Na, Cl, and K were retained under salinity in the salt tolerant genotype FL478. Also, the concentration of $Na^+$, $K^+$ and $Cl^-$ ions in leaf sheaths and leaf blades was comparable between T65 and T65lg, indicating that the lamina joint may not be involved in the exclusion of $Na^+$, $Cl^-$ and $K^+$ by the leaf sheath from the leaf blade under salinity. Therefore, we conclude that the central parenchyma cells of basal part of leaf sheath are the site that plays a physiological role to exclude $Na^+$ in the shoots of rice without the involvement of the lamina joint.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.238-238
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• 2017

Salt stress is one of the deteriorating abiotic stresses due to the climate change, which causes over-accumulation of $Na^+$ and $Cl^-$ ions in plants and inhibits the growth and yield of rice especially in coastal Southeastern Asia. The yield components of rice plant (panicle number, spikelet number per panicle, 1000-grain weight, % of ripened grains) that are majorly affected by salt stress vary with growth stages at which the plant is subjected to the stress. In addition, the salt sensitivity of each yield component differs among rice varieties even when the salt-affected growth stage was same, which indicates that the physiological mechanism to maintain each yield component is different from each other. Therefore, we hypothesized that rice plant has different genes/QTLs that contribute to the maintenance of each yield component. Using a Japanese leading rice cultivar, Koshihikari, and salt-tolerant Nona bokra's chromosome segment substitution lines (CSSLs) with the genetic background of Koshihikari (44 lines in total) (Takai et al. 2007), we screened higher yielding CSSLs under salinity in comparison to Koshihikari and identified the yield components that were improved by the introgression of chromosome segment(s) of Nona bokra. The experiment was conducted in a salinized paddy field. One-month-old seedlings were transplanted into a paddy field without salinity. These were allowed to establish for one month, and then the field was salinized by introducing saline water to maintain the surface water at 0.4% salinity until harvest. The experiments were done twice in 2015 and 2016. Although all the CSSLs and Koshihikari decreased their yield under salinity, some CSSLs showed relatively higher yield compared with Koshihikari. In Koshihikari, all the yield components except panicle number were decreased by salinity and % of ripened grains was mostly reduced, followed by spikelet number per panicle and 1000-grain weight. When compared with Koshihikari, keeping a higher % of ripened grains under salinity attributed to the significantly greater yield in one CSSL. This indicated that the % of ripened grains is the most sensitive to salt stress among the yield components of Koshihikari and that the Nona bokra chromosome segments that maintained it contributed to increased yield under salt stress. In addition, growth analyses showed that maintaining relative growth rate in the late grain filling stage led to the increased yield under salt stress but not in earlier stages.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2002.04a
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• pp.41-47
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• 2002

Adverse environmental conditions such as drought, high salt and cold/freezing are major factors that reduces crop productivity worldwide. According to a survey, $50-80\%$ of the maximum potential yield is lost by these 'environmental or abiotic stresses', which is approximately ten times higher than the loss by biotic stresses. Thus, Improving stress-tolerance of crop plants is an important way to improve agricultural productivity. In order to develop such stress-tolerant crop plants, we set out to identify key stress signaling components that can be used to develop commercially viable crop varieties with enhanced stress tolerance. Our primary focus so far has been on the identification of transcription factors that regulate stress responsive gene expression, especially those involved in ABA-mediated stress response. Be sessile, plants have the unique capability to adapt themselves to the abiotic stresses. This adaptive capability is largely dependent on the plant hormone abscisic acid (ABA), whose level increases under various stress conditions, triggering adaptive response. Central to the response is ABA-regulated gene expression, which ultimately leads to physiological changes at the whole plant level. Thus, once identified, it would be possible to enhance stress tolerance of crop plants by manipulating the expression of the factors that mediate ABA-dependent stress response. Here, we present our work on the isolation and functional characterization of the transcription factors.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2002.04b
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• pp.41-47
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• 2002

Adverse environmental conditions such as drought, high salt and cold/freezing are major factors that reduces crop productivity worldwide. According to a survey, 50-80% of the maximum potential yield is lost by these 'environmental or abiotic stresses', which is approximately ten times higher than the loss by biotic stresses. Thus, improving stress-tolerance of crop plants is an important way to improve agricultural productivity. In order to develop such stress-tolerant crop plants, we set out to identify key stress signaling components that can be used to develop commercially viable crop varieties with enhanced stress tolerance. Our primary focus so far has been on the identification of transcription factors that regulate stress responsive gene expression, especially those involved in ABA-mediated stress response. Be sessile, plants have the unique capability to adapt themselves to the abiotic stresses. This adaptive capability is largely dependent on the plant hormone abscisic acid (ABA), whose level increases under various stress conditions, triggering adaptive response. Central to the response is ABA-regulated gene expression, which ultimately leads to physiological changes at the whole plant level. Thus, once identified, it would be possible to enhance stress tolerance of crop plants by manipulating the expression of the factors that mediate ABA-dependent stress response. Here, we present our work on the isolation and functional characterization of the transcription factors.