Involvement of Jasmonate Signaling Components in Salt Stress-Induced Stomatal Closure in Arabidopsis thaliana

To clarify a possible role of jasmonate signaling in regulation of the state of stomata under salt stress, the effect of the treatment ofArabidopsis thalianaL. plant leaves (wild type and mutants deficient in jasmonate signaling) with sodium chloride (50-200 mM) and/or methyl jasmonate (200 mu M) was studied. A 2-3-h effect of NaCl induced stomatal closure in wild-type plants (Col-0). The most noticeable effect was observed under the influence of 100 mM sodium chloride. At the same time, NaCl treatment of the leaves of thejin1mutant, deficient by the gene encoding the JIN1/MYC2 transcription factor, had hardly any effect on the state of the stomata. Only a slight decrease in stomatal aperture occurred under the influence of salt in the plants of thecoi1genotype (mutants by the gene encoding the COI1 protein, which is involved in the removal of jasmonate signaling transcriptional factors' repressors). A 3-h treatment of leaves with 200 mu M methyl jasmonate caused a noticeable stomatal closure in wild-type plants but not injin1andcoi1mutants. With the combined effect of methyl jasmonate and salt on the leaves of Arabidopsis of three genotypes, a trend towards additional decrease in the stomatal aperture was manifested only in wild-type plants. A conclusion was drawn on the role of jasmonate and its signal transduction system in the regulation of stomatal movements under salt stress.