title: Disrupted actin dynamics trigger an increment in the reactive oxygen species levels in the Arabidopsis root under salt stress.
abstract: Changes in actin dynamics represent the primary response of the plant cell to extracellular signaling. Recent studies have now revealed that actin remodeling is involved in abiotic stress tolerance in plants. In our current study, the relationship between the changes in actin dynamics and the reactive oxygen species (ROS) level at the initial stages of salt stress was investigated in the elongation zone of the Arabidopsis root tip. We found that a 200 mM NaCl treatment disrupted the dynamics of the actin filaments within 10 min and increased the ROS levels in the elongation zone cells of the Arabidopsis root tip. We further found that the NADPH oxidase activity inhibitor, diphenyleneiodonium, treatment blocked this ROS increase under salt stress conditions. The roles of actin dynamics and the NADPH oxidases in ROS generation were further analyzed using the actin-specific agents, latrunculin B (Lat-B) and jasplakinolide (Jasp), and mutants of Arabidopsis NADPH oxidase AtrbohC. Lat-B and Jasp promote actin depolymerization and polymerization, respectively, and both were found to enhance the ROS levels following NaCl treatment. However, this response was abolished in the atrbohC mutants. Our present results thus demonstrate that actin dynamics are involved in regulating the ROS level in Arabidopsis root under salt stress conditions.
  
  
  CONCLUSIONS
  Salt stress disrupts the dynamics of the actin filaments in Arabidopsis in the short term which are involved in regulating the ROS levels that arise under salt stress conditions via the actions of the AtrbohC.
authors.affiliation: State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian 271018, Shandong, China.
authors.forename: Shang Gang
authors.initials: SG
authors.lastname: Liu
authors.forename: Dong Zi
authors.initials: DZ
authors.lastname: Zhu
authors.forename: Guang Hui
authors.initials: GH
authors.lastname: Chen
authors.forename: Xin-Qi
authors.initials: XQ
authors.lastname: Gao
authors.forename: Xian Sheng
authors.initials: XS
authors.lastname: Zhang
mesh_terms: D000199:Actins / Q000378:metabolism*; D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D047630:Depsipeptides / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant; D018519:Meristem / Q000378:metabolism; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012965:Sodium Chloride / Q000494:pharmacology*; D013312:Stress, Physiological; D053778:Thiazolidines / Q000494:pharmacology
chemical_list: D000199:Actins; D019086:Bridged Bicyclo Compounds, Heterocyclic; D047630:Depsipeptides; D017382:Reactive Oxygen Species; D053778:Thiazolidines; C057531:jasplakinolide; D012965:Sodium Chloride; D019255:NADPH Oxidases; C037068:latrunculin B