Effect of nitric oxide donor on salt resistance of Arabidopsis jin1 mutants and wild-type plants

The effect of NO donor sodium nitroprusside (SNP) on salt resistance of 4-week-old Arabidopsis thaliana L. wild-type Columbia-0 (Col-0) plants and jin1 mutants defective in the jasmonate signaling have been investigated. As affected by 0.5 mM, SNP salt resistance of wild-type plants rose, which was exhibited in a smaller growth inhibition and preserving the pool of photosynthetic pigments after salt stress (200 mM NaCl). The positive effect of SNP leveled by treatment of plant with NO scavenger: 0.5 mM PTIO (2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide). However, SNP treatment had no significant effect on the salt tolerance of jin1 genotype plants. In the case of wild-type plants but not jin1 mutants, treatment by NO donor increased activity of antioxidant enzymes-superoxide dismutase, guaiacol peroxidase, and catalase-in the leaves, which was especially noticeable in salt stress conditions. In wild-type plants treated by NO donor, proline content in the leaves after salt stress was lower and sugar content was higher than that in the untreated ones. In jin1 mutants, NO donor treatment resulted in a significant increase in proline content in the leaves under salt stress, without changing sugar content. A conclusion was made on the participation of transcript factor JIN1/MYC2 in NO-dependent induction of some plant defense responses to salt stress.