title: Control of Tobacco mosaic virus by PopW as a result of induced resistance in tobacco under greenhouse and field conditions.
abstract: In a previous study, we isolated a new harpin protein, PopW, from the bacterium Ralstonia solanacearum ZJ3721 that can induce a hypersensitive response in tobacco, Nicotiana tabacum, leaves. In the current study, we demonstrate that, in a greenhouse experiment, PopW induced tobacco-acquired resistance against the Tobacco mosaic virus (TMV) with a biocontrol efficacy of 80.9 to 97.4% at a concentration as low as 25 μg/ml in both PopW-treated and neighboring leaves. The resistance induced by PopW is systemic acquired resistance mediated by salicylic acid, which was certified by the development of resistance being accompanied by the expression of the pathogenesis-related-1 gene (PR1) 8 h after PopW was sprayed onto the tobacco leaves. In addition, hydrogen peroxide began to accumulate 10 h after PopW spraying, peaking at 24 h with a maximum concentration of 1.97 μM/g fresh weight. The activities of phenylalanine ammonia lyase (EC4.3.1.5), polyphenoloxidase (EC1.14.18.1), and peroxidase (EC1.11.1.7) also increased, peaking at different times in the PopW-treated tobacco leaves. PopW also reduced the level of TMV disease in field trials with a biocontrol efficacy of 45.2%. Furthermore, PopW both increased tobacco yield (by 30.4 more than in control plants) and improved tobacco foliar quality, with an increase of 50.2% in the number of first-class tobacco leaves from treated compared with untreated plants. All of these results indicate that the new harpin protein PopW has the potential to be an effective biocontrol agent against TMV in tobacco.
authors.affiliation: Department of Plant Pathology, Nanjing Agricultural University, Jiangsu Province, China.
authors.forename: Jian-Gang
authors.initials: JG
authors.lastname: Li
authors.forename: Jing
authors.initials: J
authors.lastname: Cao
authors.forename: Fei-Fei
authors.initials: FF
authors.lastname: Sun
authors.forename: Dong-Dong
authors.initials: DD
authors.lastname: Niu
authors.forename: Fang
authors.initials: F
authors.lastname: Yan
authors.forename: Hong-Xia
authors.initials: HX
authors.lastname: Liu
authors.forename: Jian-Hua
authors.initials: JH
authors.lastname: Guo
mesh_terms: D000704:Analysis of Variance; D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D004156:Catechol Oxidase / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D009195:Peroxidase / Q000378:metabolism; D010650:Phenylalanine Ammonia-Lyase / Q000378:metabolism; D010935:Plant Diseases / Q000276:immunology* / Q000821:virology; D057865:Plant Immunity; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics / Q000276:immunology / Q000821:virology; D010940:Plant Proteins / Q000235:genetics; D043368:Ralstonia solanacearum / Q000235:genetics; D013997:Time Factors; D014026:Nicotiana / Q000201:enzymology / Q000235:genetics / Q000276:immunology* / Q000821:virology; D014027:Tobacco Mosaic Virus / Q000276:immunology* / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D010940:Plant Proteins; C053376:pathogenesis-related proteins, plant; D006861:Hydrogen Peroxide; D004156:Catechol Oxidase; D009195:Peroxidase; D010650:Phenylalanine Ammonia-Lyase