title: cGMP and ethylene are involved in maintaining ion homeostasis under salt stress in Arabidopsis roots.
abstract: CONCLUSIONS
  cGMP promotes ethylene production and enhances the perception of ethylene. Endogenous ethylene or cGMP accumulation maintains ion homeostasis to enhancing salt resistance. etr1 - 3 is insensitive to cGMP under salt stress.
  In the present study, we presented a signaling network involving ethylene and cGMP in salt resistance pathway of Arabidopsis roots. Results showed that the ethylene-insensitive mutant etr1-3 was more sensitive to salt stress than the wild type (WT). etr1-3 displayed a greater electrolyte leakage, thiobarbituric acid reactive substances and Na(+)/K(+) ratio, but a lower plasma membrane (PM) H(+)-ATPase activity compared to WT under the different NaCl contents. Application of 1-aminocyclopropane-1-carboxylic acid (ACC, an ethylene precursor) or 8-Br-cGMP (the cGMP analog) alleviated NaCl-induced injury by maintaining a lower Na(+)/K(+) ratio and increasing PM H(+)-ATPase activity in WT, but not in etr1-3. Roots treated with 8-Br-cGMP could promote ethylene production and enhance the expression of ACC synthase gene in WT. In addition, the 8-Br-cGMP action in NaCl stress was inhibited by aminooxyacetic acid (an inhibitor of ethylene biosynthesis), but 6-Anilino-5,8-quinolinedione (Ly83583, a guanylate cyclase inhibitor) could not affect ACC action in WT. These results suggest that ethylene functions as a downstream signal of cGMP that stimulates the PM H(+)-ATPase activity, which finally results in regulating ion homeostasis in Arabidopsis tolerance to salt. Moreover, cGMP enhanced the perception of ethylene in Arabidopsis under salt stress, which reversed the salt-induced increase of ETR1 and increased ERF1 at the transcript levels in WT. In a word, cGMP modulates salt resistance pathway of ethylene through regulating biosynthesis and perception of ethylene in Arabidopsis roots.
authors.affiliation: College of Life Sciences, Northwest A&F University, Yangling, 712100, Shaanxi, China, lijsh2011@163.com.
authors.forename: Jisheng
authors.initials: J
authors.lastname: Li
authors.forename: Honglei
authors.initials: H
authors.lastname: Jia
authors.forename: Jue
authors.initials: J
authors.lastname: Wang
mesh_terms: D000598:Amino Acids, Cyclic / Q000494:pharmacology; D017360:Arabidopsis / Q000187:drug effects* / Q000378:metabolism*; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000494:pharmacology*; D005030:Ethylenes / Q000494:pharmacology*; D007477:Ions / Q000378:metabolism*; D018517:Plant Roots / Q000187:drug effects* / Q000378:metabolism*; D012965:Sodium Chloride / Q000494:pharmacology
chemical_list: D000598:Amino Acids, Cyclic; D005030:Ethylenes; D007477:Ions; C016276:8-bromocyclic GMP; C023863:1-aminocyclopropane-1-carboxylic acid; D012965:Sodium Chloride; C036216:ethylene; D006152:Cyclic GMP