title: Melatonin induces nitric oxide and the potential mechanisms relate to innate immunity against bacterial pathogen infection in Arabidopsis.
abstract: Melatonin (N-acetyl-5-methoxytryptamine) is a naturally occurring small molecule, serving as important secondary messenger in the response of plants to various biotic and abiotic stresses. However, the interactions between melatonin and other important molecules in the plant stress response, especially in plant immunity, are largely unknown. In this study, we found that both melatonin and nitric oxide (NO) levels in Arabidopsis leaves were significantly induced by bacterial pathogen (Pst DC3000) infection. The elevated NO production was caused by melatonin as melatonin application enhanced endogenous NO level with great efficacy. Moreover, both melatonin and NO conferred improved disease resistance against Pseudomonas syringe pv. tomato (Pst) DC3000 infection in Arabidopsis. NO scavenger significantly suppressed the rise of NO which was induced by exogenous application of melatonin. As a result, the beneficial effects of melatonin on the expression of salicylic acid (SA)-related genes and disease resistance against bacterial pathogen infection were jeopardized by use of a NO scavenger. Consistently, melatonin application significantly lost its effect on the innate immunity against P. syringe pv. tomato (Pst) DC3000 infection in NO-deficient mutants of Arabidopsis. The results indicate that melatonin-induced NO production is responsible for innate immunity response of Arabidopsis against Pst DC3000 infection.
authors.affiliation: Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Agriculture, Hainan University, Haikou, China.
authors.forename: Haitao
authors.initials: H
authors.lastname: Shi
authors.affiliation: Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Agriculture, Hainan University, Haikou, China.
authors.forename: Yinhua
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Cellular and Structural Biology, The University of Texas Health Science Center, San Antonio, TX, USA.
authors.forename: Dun-Xian
authors.initials: DX
authors.lastname: Tan
authors.affiliation: Department of Cellular and Structural Biology, The University of Texas Health Science Center, San Antonio, TX, USA.
authors.forename: Russel J
authors.initials: RJ
authors.lastname: Reiter
authors.affiliation: Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China.
authors.forename: Zhulong
authors.initials: Z
authors.lastname: Chan
authors.affiliation: Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Agriculture, Hainan University, Haikou, China.
authors.forename: Chaozu
authors.initials: C
authors.lastname: He
mesh_terms: D017360:Arabidopsis / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism / Q000382:microbiology*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D007113:Immunity, Innate / Q000187:drug effects; D008550:Melatonin / Q000494:pharmacology*; D009569:Nitric Oxide / Q000378:metabolism; D010935:Plant Diseases / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control; D044224:Pseudomonas syringae / Q000276:immunology / Q000472:pathogenicity*
chemical_list: D009569:Nitric Oxide; D008550:Melatonin
keywords: Arabidopsis; bacterial pathogen; melatonin; nitric oxide; plant innate immunity