title: Ethylene contributes to potato aphid susceptibility in a compatible tomato host.
abstract: Resistance to potato aphid (Macrosiphum euphorbiae) in tomato (Solanum lycopersicum) is conferred by Mi-1. Early during both compatible and incompatible interactions, potato aphid feeding induces the expression of ethylene (ET) biosynthetic genes. Here, we used genetic and pharmacologic approaches to investigate the role of ET signaling in basal defense and Mi-1-mediated resistance to potato aphid in tomato. The effect of potato aphid infestation on ET biosynthesis in susceptible and resistant plants was assessed. Aphid bioassays were performed using plants impaired in ET biosynthesis or perception using virus-induced gene silencing, the Never ripe (Nr) mutant, and 1-methylcyclopropene (MCP) treatment. A burst of ET was observed after aphid feeding in both resistant and susceptible plants, correlated with an increase in the expression of ET biosynthetic genes. However, impairing ET signaling or biosynthesis did not compromise Mi-1-mediated resistance but it did decrease susceptibility to potato aphid in a compatible host. ET may not play a significant role in Mi-1-mediated resistance to potato aphids in tomato but modulates the host basal defense, enhancing its susceptibility to the aphid.
authors.affiliation: Department of Nematology, University of California, Riverside, CA 92521, USA.
authors.forename: Sophie
authors.initials: S
authors.lastname: Mantelin
authors.affiliation: Department of Nematology, University of California, Riverside, CA 92521, USA.
authors.forename: Kishor K
authors.initials: KK
authors.lastname: Bhattarai
authors.affiliation: Department of Nematology, University of California, Riverside, CA 92521, USA.
authors.forename: Isgouhi
authors.initials: I
authors.lastname: Kaloshian
mesh_terms: D000818:Animals; D001042:Aphids / Q000187:drug effects / Q000472:pathogenicity / Q000502:physiology*; D001681:Biological Assay; D003521:Cyclopropanes / Q000494:pharmacology; D005030:Ethylenes / Q000096:biosynthesis / Q000378:metabolism*; D020224:Expressed Sequence Tags; D005247:Feeding Behavior / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D020868:Gene Silencing / Q000187:drug effects; D017343:Genes, Plant; D006790:Host-Parasite Interactions / Q000187:drug effects; D007113:Immunity, Innate / Q000187:drug effects; D018551:Solanum lycopersicum / Q000187:drug effects / Q000235:genetics / Q000469:parasitology*; D010935:Plant Diseases / Q000276:immunology / Q000469:parasitology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D011198:Solanum tuberosum / Q000187:drug effects / Q000276:immunology* / Q000469:parasitology*; D014774:Virulence / Q000187:drug effects
chemical_list: D003521:Cyclopropanes; D005030:Ethylenes; D012333:RNA, Messenger; C036216:ethylene; C412563:1-methylcyclopropene