title: Elicitor-induced defense responses in Solanum lycopersicum against Ralstonia solanacearum.
abstract: We investigated on important parameters of induced resistance in hydroponic tomato (Solanum lycopersicum) against Ralstonia solanacearum using the elicitors chitosan (CHT), salicylic acid (SA), and jasmonic acid (JA). The increase in total phenolic content of roots by the elicitors was significantly higher than control. Most pronounced increase in lignin synthesis was triggered by SA followed by CHT. At 24 h post-elicitation (hpe), the activity of phenylalanine ammonia lyase was 4.5 times higher than control elicited by CHT. The peroxidase activity was about 86 nkat/mg protein at 24 hpe in case of SA and 78 nkat/mg protein in case of CHT. The activity of polyphenol oxidase increased several folds by the elicitors. Cinnamyl alcohol dehydrogenase activity increased to the maximum at 48 hpe under the influence of CHT. The results indicate that the elicitors SA and CHT induced effective defense responses in tomato plants against R. solanacearum. This was evident from reduced vascular browning and wilting symptoms of tomato plants treated with SA and CHT and challenged subsequently with R. solanacearum. This reduced disease incidence in tomato by SA and CHT may be a result of cell wall strengthening through deposition of lignin and the coincident induction of defense enzymes.
authors.affiliation: Plant Pathology Laboratory, Central Horticultural Experiment Station (ICAR), Aiginia, Bhubaneswar 751019, India.
authors.forename: Sudhamoy
authors.initials: S
authors.lastname: Mandal
authors.forename: Itishree
authors.initials: I
authors.lastname: Kar
authors.forename: Arup K
authors.initials: AK
authors.lastname: Mukherjee
authors.forename: Priyambada
authors.initials: P
authors.lastname: Acharya
mesh_terms: D000429:Alcohol Oxidoreductases / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D004156:Catechol Oxidase / Q000378:metabolism; D048271:Chitosan / Q000494:pharmacology; D003517:Cyclopentanes / Q000494:pharmacology; D054884:Host-Pathogen Interactions / Q000187:drug effects / Q000502:physiology; D018527:Hydroponics; D008031:Lignin / Q000096:biosynthesis; D018551:Solanum lycopersicum / Q000187:drug effects* / Q000382:microbiology* / Q000502:physiology; D054883:Oxylipins / Q000494:pharmacology; D010544:Peroxidases / Q000378:metabolism; D010636:Phenols / Q000378:metabolism; D010650:Phenylalanine Ammonia-Lyase / Q000378:metabolism; D010935:Plant Diseases / Q000382:microbiology* / Q000517:prevention & control; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism; D043368:Ralstonia solanacearum / Q000472:pathogenicity*; D020156:Salicylic Acid / Q000494:pharmacology
chemical_list: D003517:Cyclopentanes; D054883:Oxylipins; D010636:Phenols; C011006:jasmonic acid; D008031:Lignin; D048271:Chitosan; D000429:Alcohol Oxidoreductases; C018656:cinnamyl alcohol dehydrogenase; D004156:Catechol Oxidase; D010544:Peroxidases; D002374:Catalase; D010650:Phenylalanine Ammonia-Lyase; D020156:Salicylic Acid