Involvement of abscisic acid in the response of Medicago sativa plants in symbiosis with Sinorhizobium meliloti to salinity.
Legumes are classified as salt-sensitive crops with their productivity particularly affected by salinity. Abcisic acid (ABA) plays an important role in the response to environmental stresses as signal molecule which led us to study its role in the response of nitrogen fixation and antioxidant metabolism in root nodules of Medicago sativa under salt stress conditions. Adult plants inoculated with Sinorhizobium meliloti were treated with 1 μM and 10 μM ABA two days before 200 mM salt addition. Exogenous ABA together with the salt treatment provoked a strong induction of the ABA content in the nodular tissue which alleviated the inhibition induced by salinity in the plant growth and nitrogen fixation. Antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) were induced by ABA pre-treatments under salt stress conditions which together with the reduction of the lipid peroxidation, suggest a role for ABA as signal molecule in the activation of the nodular antioxidant metabolism. Interaction between ABA and polyamines (PAs), described as anti-stress molecules, was studied being detected an induction of the common polyamines spermidine (Spd) and spermine (Spm) levels by ABA under salt stress conditions. In conclusion, ABA pre-treatment improved the nitrogen fixation capacity under salt stress conditions by the induction of the nodular antioxidant defenses which may be mediated by the common PAs Spd and Spm that seems to be involved in the anti-stress response induced by ABA.
Departamento de Fisiología Vegetal, Facultad de Ciencias, Universidad de Granada, Campus de Fuentenueva s/n, 18071 Granada, Spain.
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Palma
Departamento de Fisiología Vegetal, Facultad de Ciencias, Universidad de Granada, Campus de Fuentenueva s/n, 18071 Granada, Spain. Electronic address: mlgomez@ugr.es.
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López-Gómez
Departamento de Fisiología Vegetal, Facultad de Ciencias, Universidad de Granada, Campus de Fuentenueva s/n, 18071 Granada, Spain.
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Tejera
Departamento de Fisiología Vegetal, Facultad de Ciencias, Universidad de Granada, Campus de Fuentenueva s/n, 18071 Granada, Spain.
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Lluch
D000040:Abscisic Acid / Q000494:pharmacology*; D000975:Antioxidants / Q000378:metabolism; D001205:Ascorbic Acid / Q000378:metabolism; D018533:Biomass; D005978:Glutathione / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D000455:Medicago sativa / Q000187:drug effects / Q000254:growth & development / Q000382:microbiology* / Q000502:physiology*; D009586:Nitrogen Fixation / Q000187:drug effects; D018520:Plant Shoots / Q000187:drug effects; D011073:Polyamines / Q000378:metabolism; D011392:Proline / Q000378:metabolism; D053204:Root Nodules, Plant / Q000187:drug effects / Q000201:enzymology; D054712:Salinity; D016962:Sinorhizobium meliloti / Q000187:drug effects / Q000502:physiology*; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological / Q000187:drug effects; D013559:Symbiosis / Q000187:drug effects*
D000975:Antioxidants; D011073:Polyamines; D012965:Sodium Chloride; D000040:Abscisic Acid; D011392:Proline; D006861:Hydrogen Peroxide; D005978:Glutathione; D001205:Ascorbic Acid
Abscisic acid; Medicago sativa; Nodule; Polyamines; Salt stress