Salicylic acid-altering Arabidopsis mutants response to salt stress
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The role of salicylic acid (SA) in plant responses to salinity is still a matter of controversy. To address the effect of endogenous SA variation in level and signaling on plant responses to salinity, biochemical and physiological analyses were performed on SA-altering Arabidopsis mutants including snc1 with high level of SA, transgenic line nahG with low SA, npr1-1 with SA signaling blockage, snc1/nahG plants (expression of nahG in the snc1 background), as well as wild type plants.
Plants were cultured in 1 × Hoagland solution under controlled conditions. For salt exposure, NaCl at final concentrations of 100 mM, 200 mM, and 300 mM, respectively, was added to the culture solution after 25 d of seed germination. Except where mentioned, plant leaves were harvested after 14 d of salt stress, and used for physiological and chemical analyses.
Salt stress caused all plants growth retardation with a dose-effect relationship relative to control. However, compared to wild type plants, a greater growth inhibition occurred in snc1, while a less inhibition was observed in nahG and npr1-1 plants, and a comparable extent was detected in snc1/nahG plants in which the SA level was near to that in wild type plants. The snc1 plants had lower net photosynthetic rate, variable to maximum fluorescence ratio, quantum efficiency of photosystem 2, reduced glutathione/oxidized glutathione ratio, proline levels, and higher malondiadehyde levels and electrolyte leakage rates as compared to wild type plants under salt stress. These values were effectively reversed by the expression of nahG gene in snc1 plants. The nahG and npr1-1 plants always exhibited more tolerance to salinity in above-mentioned indices than wild type plants. However, higher activities of superoxide dismutase and peroxidase in snc1 plants did not contribute to salt tolerance.
These data showed that SA deficit or signaling blockage in Arabidopsis plants was favorable to salt adaptation, while a high accumulation of SA potentiated salt-induced damage to Arabidopsis plants.
KeywordsSalt stress Salicylic acid Oxidative damage Photosynthesis Glutathione Proline
variable to maximum fluorescence ratio
naphthalene hydroxylase G
nonexpressor of pathogenesis-relative gene 1
net photosynthetic rate
reactive oxygen species
suppressor of npr1-1 constitutive 1
quantum efficiency of photosystem 2.
We thank X. Dong for Arabidopsis mutants (Duke University, Durham, NC). This research was supported by the National Natural Science Foundation of China (grant No. 30570445), the Natural Science Foundation of Education Department of Liaoning Province (Project No. LS2010152), and Director Foundation of Experimental Centre, Shenyang Normal University (SY200802).
- Aebi HE (1983) Catalase. In: Bergmeyer HU (ed) Methods of enzymatic analyses. Weinheim, Verlag Chemie, pp 273–282Google Scholar
- Banu MN, Hoque MA, Watanabe-Sugimoto M, Islam MM, Uraji MK, Nakamura Y, Murata Y (2010) Proline and glycinebetaine ameliorated NaCl stress via scavenging of hydrogen peroxide and methylglyoxal but not superoxide or nitric oxide in tobacco cultured cells. Biosci Biotechnol Biochem 74:2043–2049PubMedCrossRefGoogle Scholar
- Jeanjean R, Matthijs HCP, Onana B, Havaux M, Joset F (1993) Exposure of the Cyanobacterium synechocystis PCC6803 to salt stress induces concerted changes in respiration and photosynthesis. Plant Cell Physiol 34:1073–1079Google Scholar
- Newman MA, van Roepenack-Lahaye E, Parr A, Daniels MJ, Dow JM (2001) Induction of hydroxycinnamoyl-tyramine conjugates in pepper by Xanthomonas campestris: a plant defense response activated by hrp gene-dependent and -independent mechanisms. Mol Plant Microbe Interact 14:785–792PubMedCrossRefGoogle Scholar
- Noreen Z, Ashraf M, Akram NA (2010) Salt-induced regulation of some key antioxidant enzymes and physio-biochemical phenomena in five diverse cultivars of turnip (Brassica rapa L.). J Agron Crop Sci 196:273–285Google Scholar
- Pitman MG, Läuchli A (2002) Global impacts of salinity and agricultural ecosystem. In: Läuchli A, Lüttge U (eds) Salinity: environment-plants-molecules. Kluwer, Dordrecht, the Netherlands, pp 3–20Google Scholar
- Poór P, Gémes K, Horváth F, Szepesi A, Simon ML, Tari I (2011) Salicylic acid treatment via the rooting medium interferes with stomatal response, CO2 fixation rate and carbohydrate metabolism in tomato, and decreases harmful effects of subsequent salt stress. Plant Biol (Stuttg) 13:105–114CrossRefGoogle Scholar
- Szepesi A, Csiszár J, Gémes K, Horváth E, Horváth F, Simon ML, Tari I (2009) Salicylic acid improves acclimation to salt stress by stimulating abscisic aldehyde oxidase activity and abscisic acid accumulation, and increases Na+ content in leaves without toxicity symptoms in Solanum lycopersicum L. J Plant Physiol 166:914–925PubMedCrossRefGoogle Scholar
- Yuan S, Lin HH (2008) Role of salicylic acid in plant abiotic stress. Z Naturforsch 63:313–320Google Scholar
- Zhang ZL, Qu WJ (2003) The Experimental Guide for Plant Physiology, 3rd edn. Higher Education Press, Beijing, China, p 70Google Scholar