title: Low concentrations of salicylic acid delay methyl jasmonate-induced leaf senescence by up-regulating nitric oxide synthase activity.
abstract: In plants, extensive efforts have been devoted to understanding the crosstalk between salicylic acid (SA) and jasmonic acid (JA) signaling in pathogen defenses, but this crosstalk has scarcely been addressed during senescence. In this study, the effect of SA application on methyl jasmonate (MeJA)-induced leaf senescence was assessed. We found that low concentrations of SA (1-50 μM) played a delayed role against the senescence promoted by MeJA. Furthermore, low concentrations of SA enhanced plant antioxidant defenses and restricted reactive oxygen species (ROS) accumulation in MeJA-treated leaves. When applied simultaneously with MeJA, low concentrations of SA triggered a nitric oxide (NO) burst, and the elevated NO levels were linked to the nitric oxide associated 1 (NOA1)-dependent pathway via nitric oxide synthase (NOS) activity. The ability of SA to up-regulate plant antioxidant defenses, reduce ROS accumulation, and suppress leaf senescence was lost in NO-deficient Atnoa1 plants. In a converse manner, exogenous addition of NO donors increased the plant antioxidant capacity and lowered the ROS levels in MeJA-treated leaves. Taken together, the results indicate that SA at low concentrations counteracts MeJA-induced leaf senescence through NOA1-dependent NO signaling and strengthening of the antioxidant defense.
authors.affiliation: MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, China.
authors.forename: Yingbin
authors.initials: Y
authors.lastname: Ji
authors.affiliation: MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
authors.affiliation: MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, China xingda@scnu.edu.cn.
authors.forename: Da
authors.initials: D
authors.lastname: Xing
mesh_terms: D000085:Acetates / Q000378:metabolism*; D000375:Aging / Q000502:physiology; D017360:Arabidopsis / Q000378:metabolism / Q000502:physiology; D002734:Chlorophyll / Q000378:metabolism; D003517:Cyclopentanes / Q000378:metabolism*; D015227:Lipid Peroxidation; D019001:Nitric Oxide Synthase / Q000378:metabolism* / Q000502:physiology; D054883:Oxylipins / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000502:physiology*; D018515:Plant Leaves / Q000502:physiology*; D060888:Real-Time Polymerase Chain Reaction; D020156:Salicylic Acid / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D000085:Acetates; D003517:Cyclopentanes; D054883:Oxylipins; D010937:Plant Growth Regulators; D002734:Chlorophyll; C072239:methyl jasmonate; D019001:Nitric Oxide Synthase; D020156:Salicylic Acid
keywords: Jasmonic acid; leaf senescence; nitric oxide; nitric oxide synthase; reactive oxygen species; salicylic acid.