title: Abscisic acid enhances resistance to Alternaria solani in tomato seedlings.
abstract: The plant hormone abscisic acid (ABA) is an important regulator in many aspects of plant growth and development, as well as stress resistance. Here, we investigated the effects of exogenous ABA application on the interaction between tomato (Solanum lycopersicon L.) and Alternaria solani (early blight). Foliar spraying of 7.58 μM ABA was effective in reducing disease severity in tomato plants. Previously, increased activities of phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO) and peroxidase (POD) were observed in exogenous ABA-treated tomato leaves. Moreover, these enzyme activities were maintained at higher levels in ABA-pretreated and A. solani challenged tomato plants. Tomato defense genes, such as PR1, β-1, 3-glucanase (GLU), PPO, POD, and superoxide dismutase (SOD), were rapidly and significantly up-regulated by exogenous ABA treatment. Furthermore, a subsequent challenge of ABA-pretreated plants with the pathogen A. solani resulted in higher expression of defense genes, compared to water-treated or A. solani inoculated plants. Therefore, our results suggest that exogenous ABA could enhance disease resistance against A. solani infection in tomato through the activation of defense genes and via the enhancement of defense-related enzymatic activities.
authors.affiliation: Chendu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; Graduate University of Chinese Academy of Sciences, Beijing 100039, China.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Song
authors.forename: Xinrong
authors.initials: X
authors.lastname: Ma
authors.forename: Hong
authors.initials: H
authors.lastname: Tan
authors.forename: Jinyan
authors.initials: J
authors.lastname: Zhou
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology*; D000528:Alternaria / Q000187:drug effects / Q000276:immunology / Q000502:physiology*; D004156:Catechol Oxidase / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D043326:Glucan 1,3-beta-Glucosidase / Q000187:drug effects / Q000235:genetics; D054884:Host-Pathogen Interactions / Q000187:drug effects; D018551:Solanum lycopersicum / Q000187:drug effects / Q000276:immunology / Q000382:microbiology*; D009195:Peroxidase / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D010650:Phenylalanine Ammonia-Lyase / Q000187:drug effects / Q000378:metabolism; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology / Q000517:prevention & control; D010937:Plant Growth Regulators / Q000494:pharmacology*; D018515:Plant Leaves / Q000187:drug effects / Q000276:immunology / Q000382:microbiology; D010940:Plant Proteins / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D018749:RNA, Plant / Q000235:genetics; D036226:Seedlings / Q000187:drug effects / Q000276:immunology / Q000382:microbiology; D013482:Superoxide Dismutase / Q000187:drug effects / Q000235:genetics; D013997:Time Factors; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D018076:DNA, Complementary; D010937:Plant Growth Regulators; D010940:Plant Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; C053376:pathogenesis-related proteins, plant; D000040:Abscisic Acid; D004156:Catechol Oxidase; D009195:Peroxidase; D013482:Superoxide Dismutase; D043326:Glucan 1,3-beta-Glucosidase; D010650:Phenylalanine Ammonia-Lyase