title: Fragments of ATP synthase mediate plant perception of insect attack.
abstract: Plants can perceive a wide range of biotic attackers and respond with targeted induced defenses. Specificity in plant non-self-recognition occurs either directly by perception of pest-derived elicitors or indirectly through resistance protein recognition of host targets that are inappropriately proteolyzed. Indirect plant perception can occur during interactions with pathogens, yet evidence for analogous events mediating the detection of insect herbivores remains elusive. Here we report indirect perception of herbivory in cowpea (Vigna unguiculata) plants attacked by fall armyworm (Spodoptera frugiperda) larvae. We isolated and identified a disulfide-bridged peptide (+ICDINGVCVDA-), termed inceptin, from S. frugiperda larval oral secretions that promotes cowpea ethylene production at 1 fmol leaf(-1) and triggers increases in the defense-related phytohormones salicylic acid and jasmonic acid. Inceptins are proteolytic fragments of chloroplastic ATP synthase gamma-subunit regulatory regions that mediate plant perception of herbivory through the induction of volatile, phenylpropanoid, and protease inhibitor defenses. Only S. frugiperda larvae that previously ingested chloroplastic ATP synthase gamma-subunit proteins and produced inceptins significantly induced cowpea defenses after herbivory. Digestive fragments of an ancient and essential plant enzyme, inceptin functions as a potent indirect signal initiating specific plant responses to insect attack.
authors.affiliation: Center of Medical, Agricultural, and Veterinary Entomology, Agricultural Research Service, Chemistry Research Unit, U.S. Department of Agriculture, Gainesville, FL 32608, USA. eschmelz@gainesville.edu
authors.forename: Eric A
authors.initials: EA
authors.lastname: Schmelz
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Carroll
authors.forename: Sherry
authors.initials: S
authors.lastname: LeClere
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Phipps
authors.forename: Julia
authors.initials: J
authors.lastname: Meredith
authors.forename: Prem S
authors.initials: PS
authors.lastname: Chourey
authors.forename: Hans T
authors.initials: HT
authors.lastname: Alborn
authors.forename: Peter E A
authors.initials: PE
authors.lastname: Teal
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D025222:Chloroplast Proton-Translocating ATPases / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid; D007887:Fabaceae / Q000201:enzymology / Q000469:parasitology; D019476:Insect Proteins / Q000737:chemistry / Q000302:isolation & purification; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D018515:Plant Leaves / Q000469:parasitology; D010944:Plants / Q000201:enzymology* / Q000469:parasitology*; D018411:Spodoptera / Q000502:physiology*; D003313:Zea mays / Q000201:enzymology / Q000469:parasitology
chemical_list: D019476:Insect Proteins; D025222:Chloroplast Proton-Translocating ATPases