Fragments of ATP synthase mediate plant perception of insect attack

Plants can perceive a wide range of biotic attackers an respond with targeted induced defences. 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 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 ([sup.+][ICDINGVCVDA.sup.-], termed inceptin, from S. frugiperda larval oral secretions that promotes cowpea ethylene production at 1 fmol [leaf.sup.-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. elicitor | guard hypothesis | indirect perception | insect herbivory | plant defense