Related Experiment Video
Updated: Jul 16, 2026

Real-time In Vivo Recording of Arabidopsis Calcium Signals During Insect Feeding Using a Fluorescent Biosensor
Published on: August 15, 2017
Cowpea chloroplastic ATP synthase is the source of multiple plant defense elicitors during insect herbivory
Eric A Schmelz1, Sherry LeClere, Mark J Carroll
1Center of Medical, Agricultural, and Veterinary Entomology, United States Department of Agriculture, Agricultural Research Service, Chemistry Research Unit, Gainesville, Florida 32608, USA. eschmelz@gainesville.usda.ufl.edu
Abstract:
In cowpea (Vigna unguiculata), fall armyworm (Spodoptera frugiperda) herbivory and oral secretions (OS) elicit phytohormone production and volatile emission due to inceptin [Vu-In; (+)ICDINGVCVDA(-)], a peptide derived from chloroplastic ATP synthase gamma-subunit (cATPC) proteins. Elicitor-induced plant volatiles can function as attractants for natural enemies of insect herbivores. We hypothesized that inceptins are gut proteolysis products and that larval OS should contain a mixture of related peptides. In this study, we identified three additional cATPC fragments, namely Vu-(GE+)In [(+)GEICDINGVCVDA(-)], Vu-(E+)In [(+)EICDINGVCVDA(-)], and Vu-In(-A) [(+)ICDINGVCVD(-)]. Leaf bioassays for induced ethylene (E) production demonstrated similar effective concentration(50) values of 68, 45, and 87 fmol leaf(-1) for Vu-In, Vu-(E+)In, and Vu-(GE+)In, respectively; however, Vu-In(-A) proved inactive. Shortly following ingestion of recombinant proteins harboring cATPC sequences, larval OS revealed similar concentrations of the three elicitors with 80% of the potential inceptin-related peptides recovered. Rapidly shifting peptide ratios over time were consistent with continued proteolysis and preferential stability of inceptin. Likewise, larvae ingesting host plants with inceptin precursors containing an internal trypsin cleavage site rapidly lost OS-based elicitor activity. OS containing inceptin elicited a rapid and sequential induction of defense-related phytohormones jasmonic acid, E, and salicylic acid at 30, 120, and 240 min, respectively, and also the volatile (E)-4,8-dimethyl-1,3,7-nonatriene. Similar to established peptide signals such as systemin and flg22, amino acid substitutions of Vu-In demonstrate an essential role for aspartic acid residues and an unaltered C terminus. In cowpea, insect gut proteolysis following herbivory generates inappropriate fragments of an essential metabolic enzyme enabling plant non-self-recognition.
More Related Videos
11:50Bacterial Leaf Infiltration Assay for Fine Characterization of Plant Defense Responses using the Arabidopsis thaliana-Pseudomonas syringae Pathosystem
Published on: October 1, 2015
04:11Pattern-Triggered Oxidative Burst and Seedling Growth Inhibition Assays in Arabidopsis thaliana
Published on: May 21, 2019
Related Concept Videos
Defenses Against Pathogens and Herbivores
C4 Pathway and CAM
C4 Pathway
The C4 pathway is used by plants such as...
Protein Transport to the Inner Chloroplast Membrane
Cell Signaling in Plants
Protein Transport to the Outer Chloroplast Membrane
Two models describe the mechanism of precursor recognition and entry across the outer membrane through the TOC complex. Model 1 suggests the newly synthesized precursor binds to the TOC receptor 159 and forms a complex.
Protein Transport to the Stroma
Protein complexes called the translocon of the outer chloroplast membrane or TOC complex, and the translocon of the inner chloroplast membrane or TIC complex mediate the...