title: Hydrogen peroxide is a second messenger in the salicylic acid-triggered adventitious rooting process in mung bean seedlings.
abstract: In plants, salicylic acid (SA) is a signaling molecule that regulates disease resistance responses, such as systemic acquired resistance (SAR) and hypertensive response (HR). SA has been implicated as participating in various biotic and abiotic stresses. This study was conducted to investigate the role of SA in adventitious root formation (ARF) in mung bean (Phaseolus radiatus L) hypocotyl cuttings. We observed that hypocotyl treatment with SA could significantly promote the adventitious root formation, and its effects were dose and time dependent. Explants treated with SA displayed a 130% increase in adventitious root number compared with control seedlings. The role of SA in mung bean hypocotyl ARF as well as its interaction with hydrogen peroxide (H2O2) were also elucidated. Pretreatment of mung bean explants with N, N'-dimethylthiourea (DMTU), a scavenger for H2O2, resulted in a significant reduction of SA-induced ARF. Diphenyleneiodonium (DPI), a specific inhibitor of membrane-linked NADPH oxidase, also inhibited the effect of adventitious rooting triggered by SA treatment. The determination of the endogenous H2O2 level indicated that the seedlings treated with SA could induce H2O2 accumulation compared with the control treatment. Our results revealed a distinctive role of SA in the promotion of adventitious rooting via the process of H2O2 accumulation. This conclusion was further supported by antioxidant enzyme activity assays. Based on these results, we conclude that the accumulation of free H2O2 might be a downstream event in response to SA-triggered adventitious root formation in mung bean seedlings.
authors.affiliation: Laboratory of Plant hormone, College of Life Sciences, Nanjing Agricultural University, Nanjing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Yang
authors.affiliation: Laboratory of Plant hormone, College of Life Sciences, Nanjing Agricultural University, Nanjing, China.
authors.forename: Changhua
authors.initials: C
authors.lastname: Zhu
authors.affiliation: Laboratory of Plant hormone, College of Life Sciences, Nanjing Agricultural University, Nanjing, China.
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Ma
authors.affiliation: Laboratory of Plant hormone, College of Life Sciences, Nanjing Agricultural University, Nanjing, China.
authors.forename: Guijun
authors.initials: G
authors.lastname: Li
authors.affiliation: Laboratory of Plant hormone, College of Life Sciences, Nanjing Agricultural University, Nanjing, China.
authors.forename: Lijun
authors.initials: L
authors.lastname: Gan
authors.affiliation: CP Bio, Inc., Chino, California, United States of America.
authors.forename: Denny
authors.initials: D
authors.lastname: Ng
authors.affiliation: Laboratory of Plant hormone, College of Life Sciences, Nanjing Agricultural University, Nanjing, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Xia
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D007887:Fabaceae / Q000378:metabolism*; D016166:Free Radical Scavengers / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000378:metabolism; D018546:Hypocotyl / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism*; D020156:Salicylic Acid / Q000494:pharmacology*; D015290:Second Messenger Systems / Q000187:drug effects*; D013890:Thiourea / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D000890:Anti-Infective Agents; D016166:Free Radical Scavengers; C038983:1,3-dimethylthiourea; D006861:Hydrogen Peroxide; D013890:Thiourea; D020156:Salicylic Acid