title: Resistance of cultivated tomato to cell content-feeding herbivores is regulated by the octadecanoid-signaling pathway.
abstract: The octadecanoid signaling pathway has been shown to play an important role in plant defense against various chewing insects and some pathogenic fungi. Here, we examined the interaction of a cell-content feeding arachnid herbivore, the two-spotted spider mite (Tetranychus urticae Koch), with cultivated tomato (Lycopersicon esculentum) and an isogenic mutant line (defenseless-1 [def-1]) that is deficient in the biosynthesis of the octadecanoid pathway-derived signal, jasmonic acid (JA). Spider mite feeding and fecundity on def-1 plants was significantly greater than on wild-type plants. Decreased resistance of def-1 plants was correlated with reduced JA accumulation and expression of defensive proteinase inhibitor (PI) genes, which were induced in mite-damaged wild-type leaves. Treatment of def-1 plants with methyl-JA restored resistance to spider mite feeding and reduced the fecundity of female mites. Plants expressing a 35S::prosystemin transgene that constitutively activates the octadecanoid pathway in a Def-1-dependent manner were highly resistant to attack by spider mites and western flower thrips (Frankliniella occidentalis), another cell-content feeder of economic importance. These findings indicate that activation of the octadecanoid signaling pathway promotes resistance of tomato to a broad spectrum of herbivores. The techniques of amplified fragment length polymorphism (AFLP) and bulk segregant analysis were used to map the Def-1 gene to a region on the long arm of chromosome 3 that is genetically separable from the map position of known JA biosynthetic genes. Tight linkage of Def-1 to a T-DNA insertion harboring the maize (Zea mays) Dissociation transposable element suggests a strategy for directed transposon tagging of the gene.
authors.affiliation: Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, USA.
authors.forename: Chuanyou
authors.initials: C
authors.lastname: Li
authors.forename: Mark M
authors.initials: MM
authors.lastname: Williams
authors.forename: Ying-Tsu
authors.initials: YT
authors.lastname: Loh
authors.forename: Gyu In
authors.initials: GI
authors.lastname: Lee
authors.forename: Gregg A
authors.initials: GA
authors.lastname: Howe
mesh_terms: D000085:Acetates / Q000494:pharmacology; D000818:Animals; D001097:Arachnida / Q000254:growth & development*; D002874:Chromosome Mapping; D003517:Cyclopentanes / Q000378:metabolism / Q000494:pharmacology; D005260:Female; D005838:Genotype; D007113:Immunity, Innate / Q000187:drug effects; D007313:Insecta / Q000254:growth & development; D018551:Solanum lycopersicum / Q000187:drug effects / Q000235:genetics / Q000469:parasitology*; D009154:Mutation; D054883:Oxylipins; D010935:Plant Diseases / Q000235:genetics / Q000469:parasitology*; D010937:Plant Growth Regulators / Q000494:pharmacology; D015398:Signal Transduction / Q000502:physiology*; D013229:Stearic Acids / Q000378:metabolism*
chemical_list: D000085:Acetates; D003517:Cyclopentanes; D054883:Oxylipins; D010937:Plant Growth Regulators; D013229:Stearic Acids; C031183:stearic acid; C011006:jasmonic acid; C072239:methyl jasmonate