title: Polyamines attenuate ethylene-mediated defense responses to abrogate resistance to Botrytis cinerea in tomato.
abstract: Transgenic tomato (Solanum lycopersicum) lines overexpressing yeast spermidine synthase (ySpdSyn), an enzyme involved in polyamine (PA) biosynthesis, were developed. These transgenic lines accumulate higher levels of spermidine (Spd) than the wild-type plants and were examined for responses to the fungal necrotrophs Botrytis cinerea and Alternaria solani, bacterial pathogen Pseudomonas syringae pv tomato DC3000, and larvae of the chewing insect tobacco hornworm (Manduca sexta). The Spd-accumulating transgenic tomato lines were more susceptible to B. cinerea than the wild-type plants; however, responses to A. solani, P. syringae, or M. sexta were similar to the wild-type plants. Exogenous application of ethylene precursors, S-adenosyl-Met and 1-aminocyclopropane-1-carboxylic acid, or PA biosynthesis inhibitors reversed the response of the transgenic plants to B. cinerea. The increased susceptibility of the ySpdSyn transgenic tomato to B. cinerea was associated with down-regulation of gene transcripts involved in ethylene biosynthesis and signaling. These data suggest that PA-mediated susceptibility to B. cinerea is linked to interference with the functions of ethylene in plant defense.
authors: Department of Horticulture and Landscape Architecture, Center for Plant Environmental Stress Physiology, Purdue University, West Lafayette, Indiana 47907, USA.
authors: Savithri
authors: S
authors: Nambeesan
authors: Synan
authors: S
authors: AbuQamar
authors: Kristin
authors: K
authors: Laluk
authors: Autar K
authors: AK
authors: Mattoo
authors: Michael V
authors: MV
authors: Mickelbart
authors: Mario G
authors: MG
authors: Ferruzzi
authors: Tesfaye
authors: T
authors: Mengiste
authors: Avtar K
authors: AK
authors: Handa
mesh_terms: D020171:Botrytis / Q000472:pathogenicity*; D005030:Ethylenes / Q000378:metabolism*; D018551:Solanum lycopersicum / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000382:microbiology*; D018515:Plant Leaves / Q000378:metabolism; D030821:Plants, Genetically Modified; D013095:Spermidine / Q000378:metabolism*
chemical_list: D005030:Ethylenes; C036216:ethylene; D013095:Spermidine