• Journal of Life Science
• /
• v.17 no.5 s.85
• /
• pp.641-645
• /
• 2007

We conducted a seed germination screening under saline conditions to identify salt tolerance(sto) mutants with ethyl methane sulfonate(EMS) mutagenesis seed pool. During the screening, we identified three mutant lines that seemed to confer elevated salt tolerance in high concentrations of NaCl. At 175 mM NaCl, germination rate of sto42-14 mutant(one of the EMS salt tolerance mutants) was 7-fold higher than that of wild-type plants. Interestingly, sto42-14 mutant exhibited insensitivity to high glucose concentration and growth inhibition to gibberellin. Our results suggest that sto42-14 is involved in salt stress tolerance as well as in glucose and gibberellin response in Arabidopsis.

• Horticultural Science & Technology
• /
• v.34 no.4
• /
• pp.564-577
• /
• 2016

Salinity stress limits plant cultivation in many areas worldwide; however, persimmon (Diospyros spp.) has high tolerance to salt. Five accessions of Diospyros [three of Diospyros lotus (accession numbers 824, 846, and 847); one of Diospyros kaki var. sylvestris (869); and one of Diospyros virginiana (844)] were chosen for analysis of salinity stress. We compared the effects of salt stress on plant growth, relative water content (RWC), malondialdehyde (MDA), electrolyte leakage (EL), hydrogen peroxide content ($H_2O_2$), and antioxidative enzyme activities (superoxide dismutase, SOD; catalase, CAT; peroxidase, POD; and ascorbate peroxidase, APX) in leaves of healthy potted seedlings from each of the five accessions after salt treatment for 25 days. Salt stress affected the growth of plants in all five accessions, with all three D. lotus accessions showing the most severe effect. Salt stress increased membrane lipid peroxidation in all accessions, but a stronger increase was observed in the three D. lotus accessions. Moreover, accumulation of $H_2O_2$ was faster in salt-sensitive D. lotus compared to salt-tolerant D. virginiana 844. The activities of all antioxidant enzymes increased in D. virginiana 844 and in D. kaki var. sylvestris 869; the activities of SOD, CAT, and APX were at similar levels in D. virginiana 844 and D. kaki var. sylvestris 869, but POD activity was stimulated to a greater extent in D. virginiana 844. The activities of all antioxidant enzymes (except POD) decreased in D. lotus 824 and increased (except for SOD) in D.lotus 846. The activities of SOD and APX decreased in D. lotus 847, whereas POD and CAT activities both increased. Relative water content decreased significantly in D. lotus. No significant changes in lipid peroxidation or relevant antioxidant parameters were detected in any of the accessions in controls treated with 0.0% NaCl. D. virginiana 844 had higher antioxidant capacity in response to salinity compared to other persimmon rootstocks. These results indicate that changes of these key physiological variables are related to salinity resistance in different accessions of persimmon.

• Molecules and Cells
• /
• v.39 no.2
• /
• pp.111-118
• /
• 2016

MiR399f plays a crucial role in maintaining phosphate homeostasis in Arabidopsis thaliana. Under phosphate starvation conditions, AtMYB2, which plays a role in plant salt and drought stress responses, directly regulates the expression of miR399f. In this study, we found that miR399f also participates in plant responses to abscisic acid (ABA), and to abiotic stresses including salt and drought. Salt and ABA treatment induced the expression of miR399f, as confirmed by histochemical analysis of promoter-GUS fusions. Transgenic Arabidopsis plants overexpressing miR399f (miR399f-OE) exhibited enhanced tolerance to salt stress and exogenous ABA, but hypersensitivity to drought. Our in silico analysis identified ABF3 and CSP41b as putative target genes of miR399f, and expression analysis revealed that mRNA levels of ABF3 and CSP41b decreased remarkably in miR399f-OE plants under salt stress and in response to treatment with ABA. Moreover, we showed that activation of stress-responsive gene expression in response to salt stress and ABA treatment was impaired in miR399f-OE plants. Thus, these results suggested that in addition to phosphate starvation signaling, miR399f might also modulates plant responses to salt, ABA, and drought, by regulating the expression of newly discovered target genes such as ABF3 and CSP41b.

• Journal of Plant Biotechnology
• /
• v.32 no.1
• /
• pp.1-14
• /
• 2005

Plant responses to salinity stress is critical in determining the growth and development. Therefore, adaptability of plant to salinity stress is directly related with agriculture productivity. Salt adaptation is a result of the integrated functioning of numerous determinants that are regulated coordinately through an appropriate responsive signal transduction cascade. The cascade perceives the saline environment and exerts control over the essential mechanisms that are responsible for ion homeostasis and osmotic adjustment. Although little is known about the component elements of salt stress perception and the signaling cascade(s) in plant, the use of Arabidopsis plant as a molecular genetic tool has been provided important molecular nature of salt tolerance effectors and regulatory pathways. In this review, I summarize recent advances in understanding the molecular mechanisms of salt adaptation.

• Journal of Plant Biotechnology
• /
• v.39 no.4
• /
• pp.253-260
• /
• 2012

On the basis of the reported agriculturally valuable phenotypes resulted from ectopic overexpression of Arabidopsis vacuolar $H^+$-PPase (AVP1), we generated the Chinese cabbage lines expressing AVP1 which then subjected to salt stress to determine the AVP1 expression if it consistently confers the capability for increasing biomass and enhancing tolerance to salinity in other species. Collectively, here we demonstrate that the transgenic young plants show more vigorous growth and higher tolerance to salt stress than wild-type ones. Increased biomass phenotype by AVP1 expression was supported by comparing fresh and dry weights of transgenic and wild type plants grown under normal condition, while higher salt tolerance trait was confirmed by tracing the kinetics of photosystem II quantum yield and DAB-staining under gradually intensified salt stress induced by MS salt or NaCl, followed by normal condition.

• Plant Biotechnology Reports
• /
• v.4 no.1
• /
• pp.37-48
• /
• 2010

[ ${\Delta}^1$ ]pyrroline-5-carboxylate synthetase (P5CS) is a proline biosynthetic pathway enzyme and is known for conferring enhanced salt and drought stress in transgenics carrying this gene in a variety of plant species; however, the wild-type P5CS is subjected to feedback control. Therefore, in the present study, we used a mutagenized version of this osmoregulatory gene-P5CSF129A, which is not subjected to feedback control, for producing transgenic indica rice plants of cultivar Karjat-3 via Agrobacterium tumefaciens. We have used two types of explants for this purpose, namely mature embryo-derived callus and shoot apices. Various parameters for transformation were optimized including antibiotic concentration for selection, duration of cocultivation, addition of phenolic compound, and bacterial culture density. The resultant primary transgenic plants showed more enhanced proline accumulation than their non-transformed counterparts. This proline level was particularly enhanced in the transgenic plants of next generation ($T_1$) under 150 mM NaCl stress. The higher proline level shown by transgenic plants was associated with better biomass production and growth performance under salt stress and lower extent of lipid peroxidation, indicating that overproduction of proline may have a role in counteracting the negative effect of salt stress and higher maintenance of cellular integrity and basic physiological processes under stress.

• Korean Journal of Breeding Science
• /
• v.43 no.5
• /
• pp.391-398
• /
• 2011

Physiological responses to salinity stress were evaluated in six rice genotypes differing in their tolerance to salinity at the seedling stage. Susceptible genotypes ('Dongjingbyeo', 'Hwayeongbyeo', and 'IR29') showed salt injury symptoms (mean 8.8) and higher visual score under salt stress than that of tolerant ones ('Pokkali', 'IR74009', and 'IR73571'). As salinity affects growth and physiological parameters, the six genotypes thus showed significant reduction because of salt stress. Tolerant Japonica/Indica bred lines ('IR74009', 'IR73571') showed lower reduction, 33.9%, 34.5%, and 50%, respectively, in plant seedling height, dry shoot weight and dry root weight than those of the susceptible Japonica varieties ('Dongjingbyeo', 'Hwayeongbyeo'), and the highest reduction under salt stress was observed in dry root weight, followed by dry shoot weight and seedling height, respectively. Shoot $Na^+$ concentration of IR74099 and IR73571 was lower than that of the susceptible varieties, 'Dongjinbyeo' and 'Hwayeongbyeo'. There were no significant differences among genotypes in root $Na^+$ concentration. Shoot $K^+$ concentration showed a reverse tendency compared to shoot $Na^+$ concentration. IR74009 and IR73571 had considerably lower ratio compared to 'Dongjinbyeo' and 'Hwayeongbyeo' in $Na^+/K^+$ ratio of their shoot and was not different the tolerant check, 'Pokkali'.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.37 no.3
• /
• pp.223-230
• /
• 2017

Arabidopsis nucleoside diphosphate kinase 2 (AtNDPK2) is an upstream signaling molecule that has been shown to induce stress tolerance in plants. In this study, the AtNDPK2 gene, under the control of a stress-inducible SWPA2 promoter, was introduced into the genome of tall fescue (Festuca arundinacea Schreb.) plants. The induction of the transgene expression mediated by methyl viologen (MV) and NaCl treatments were confirmed by RT-PCR and northern blot analysis, respectively. Under salt stress treatment, the transgenic tall fescue plants (SN) exhibited lower level of $H_2O_2$ and lipid peroxidation accumulations than the non-transgenic (NT) plants. The transgenic tall fescue plants also showed higher level of NDPK enzyme activity compared to NT plants. The SN plants were survived at 300 mM NaCl treatment, whereas the NT plants were severely affected. These results indicate that stress-inducible overexpression of AtNDPK2 might efficiently confer the salt stress tolerance in tall fescue plants.

• Korean Journal of Soil Science and Fertilizer
• /
• v.49 no.4
• /
• pp.355-367
• /
• 2016

Soil salinization refers to the buildup of salts in soil to a level toxic to plants. The major factors that contribute to soil salinity are the quality, the amount and the type of irrigation water used. The presented review discusses the different sources and causes of soil salinity. The effect of soil salinity on biological processes of plants is also discussed in detail. This is followed by a debate on the influence of salt on the nutrient uptake and growth of plants. Salinity decreases the soil osmotic potential and hinders water uptake by the plants. Soil salinity affects the plants K uptake, which plays a critical role in plant metabolism due to the high concentration of soluble sodium ($Na^+$) ions. Visual symptoms that appear in the plants as a result of salinity include stunted plant growth, marginal leaf necrosis and fruit distortions. Different strategies to ameliorate salt stress globally include breeding of salt tolerant cultivars, irrigation to leach excessive salt to improve soil physical and chemical properties. As part of an ecofriendly means to alleviate salt stress and an increasing considerable attention on this area, the review then focuses on the different plant growth promoting bacteria (PGPB) mediated mechanisms with a special emphasis on ACC deaminase producing bacteria. The various strategies adopted by PGPB to alleviate various stresses in plants include the production of different osmolytes, stress related phytohormones and production of molecules related to stress signaling such as bacterial 1-aminocyclopropane-1-carboxylate (ACC) derivatives. The use of PGPB with ACC deaminase producing trait could be effective in promoting plant growth in agricultural areas affected by different stresses including salt stress. Finally, the review ends with a discussion on the various PGPB activities and the potentiality of facultative halophilic/halotolerant PGPB in alleviating salt stress.

• Journal of Microbiology and Biotechnology
• /
• v.27 no.10
• /
• pp.1790-1797
• /
• 2017

In the present study, we demonstrate that the growth of salt-stressed pepper plants is improved by inoculation with plant growth-promoting rhizobacteria (PGPR). Three PGPR strains (Microbacterium oleivorans KNUC7074, Brevibacterium iodinum KNUC7183, and Rhizobium massiliae KNUC7586) were isolated from the rhizosphere of pepper plants growing in saline soil, and pepper plants inoculated with these PGPR strains exhibited significantly greater plant height, fresh weight, dry weight, and total chlorophyll content than non-inoculated plants. In addition, salt-stressed pepper plants that were inoculated with B. iodinum KNUC7183 and R. massiliae KNUC7586 possessed significantly different total soluble sugar and proline contents from non-inoculated controls, and the activity of several antioxidant enzymes (ascorbate peroxidase, guaiacol peroxidase, and catalase) was also elevated in PGPR-treated plants under salt stress. Overall, these results suggest that the inoculation of pepper plants with M. oleivorans KNUC7074, B. iodinum KNUC7183, and R. massiliae KNUC7586 can alleviate the harmful effects of salt stress on plant growth.