title: Constitutive expression of mammalian nitric oxide synthase in tobacco plants triggers disease resistance to pathogens.
abstract: Nitric oxide (NO) is known for its role in the activation of plant defense responses. To examine the involvement and mode of action of NO in plant defense responses, we introduced calmodulin-dependent mammalian neuronal nitric oxide synthase (nNOS), which controls the CaMV35S promoter, into wild-type and NahG tobacco plants. Constitutive expression of nNOS led to NO production and triggered spontaneous induction of leaf lesions. Transgenic plants accumulated high amounts of H(2)O(2), with catalase activity lower than that in the wild type. nNOS transgenic plants contained high levels of salicylic acid (SA), and they induced an array of SA-, jasmonic acid (JA)-, and/or ethylene (ET)-related genes. Consequently, NahG co-expression blocked the induction of systemic acquired resistance (SAR)-associated genes in transgenic plants, implying SA is involved in NO-mediated induction of SAR genes. The transgenic plants exhibited enhanced resistance to a spectrum of pathogens, including bacteria, fungi, and viruses. Our results suggest a highly ranked regulatory role for NO in SA-, JA-, and/or ET-dependent pathways that lead to disease resistance.
authors.affiliation: Division of Applied Life Science (Brain Korea 21 Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701, Korea.
authors.forename: Hyun Jin
authors.initials: HJ
authors.lastname: Chun
authors.forename: Hyeong Cheol
authors.initials: HC
authors.lastname: Park
authors.forename: Sung Cheol
authors.initials: SC
authors.lastname: Koo
authors.forename: Ju Huck
authors.initials: JH
authors.lastname: Lee
authors.forename: Chan Young
authors.initials: CY
authors.lastname: Park
authors.forename: Man Soo
authors.initials: MS
authors.lastname: Choi
authors.forename: Chang Ho
authors.initials: CH
authors.lastname: Kang
authors.forename: Dongwon
authors.initials: D
authors.lastname: Baek
authors.forename: Yong Hwa
authors.initials: YH
authors.lastname: Cheong
authors.forename: Dae-Jin
authors.initials: DJ
authors.lastname: Yun
authors.forename: Woo Sik
authors.initials: WS
authors.lastname: Chung
authors.forename: Moo Je
authors.initials: MJ
authors.lastname: Cho
authors.forename: Min Chul
authors.initials: MC
authors.lastname: Kim
mesh_terms: D000818:Animals; D003517:Cyclopentanes / Q000378:metabolism; D060467:Disease Resistance / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D006861:Hydrogen Peroxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000235:genetics* / Q000378:metabolism; D054883:Oxylipins / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D011549:Pseudomonas / Q000235:genetics / Q000502:physiology*; D051381:Rats; D020156:Salicylic Acid / Q000378:metabolism; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism / Q000382:microbiology*
chemical_list: D003517:Cyclopentanes; D054883:Oxylipins; C011006:jasmonic acid; D006861:Hydrogen Peroxide; D019001:Nitric Oxide Synthase; D020156:Salicylic Acid