title: Caterpillar- and salivary-specific modification of plant proteins.
abstract: Though there is overlap, plant responses to caterpillar herbivory show distinct variations from mechanical wounding. In particular, effectors in caterpillar oral secretions modify wound-associated plant responses. Previous studies have focused on transcriptional and protein abundance differences in response to caterpillar herbivory. This study investigated Spodoptera exigua caterpillar-specific post-translational modification of Arabidopsis thaliana soluble leaf proteins by liquid chromatography/electrospray ionization/mass spectroscopy/mass spectroscopy (LC/ESI/MS/MS). Given that caterpillar labial saliva contains oxidoreductases, such as glucose oxidase, particular attention was paid to redox-associated modifications, such as the oxidation of protein cysteine residues. Caterpillar- and saliva-specific protein modifications were observed. Differential phosphorylation of the jasmonic acid biosynthetic enzyme, lipoxygenase 2, and a chaperonin protein is seen in plants fed upon by caterpillars with intact salivary secretions compared to herbivory by larvae with impaired labial salivary secretions. Often a systemic suppression of photosynthesis is associated with caterpillar herbivory. Of the five proteins modified in a caterpillar-specific manner (a transcription repressor, a DNA-repair enzyme, PS I P700, Rubisco and Rubisco activase), three are associated with photosynthesis. Oxidative modifications are observed, such as caterpillar-specific denitrosylation of Rubisco activase and chaperonin, cysteine oxidation of Rubisco, DNA-repair enzyme, and chaperonin and caterpillar-specific 4-oxo-2-nonenal modification of the DNA-repair enzyme.
authors.affiliation: Department of Plant Science, McGill University, Ste-Anne-de-Bellevue, Québec, Canada.
authors.forename: Karine
authors.initials: K
authors.lastname: Thivierge
authors.forename: Alberto
authors.initials: A
authors.lastname: Prado
authors.forename: Brian T
authors.initials: BT
authors.lastname: Driscoll
authors.forename: Eric
authors.initials: E
authors.lastname: Bonneil
authors.forename: Pierre
authors.initials: P
authors.lastname: Thibault
authors.forename: Jacqueline C
authors.initials: JC
authors.lastname: Bede
mesh_terms: D000818:Animals; D029681:Arabidopsis Proteins / Q000032:analysis / Q000378:metabolism*; D007814:Larva; D013058:Mass Spectrometry; D010084:Oxidation-Reduction; D018515:Plant Leaves / Q000737:chemistry; D010940:Plant Proteins / Q000378:metabolism; D011499:Protein Processing, Post-Translational / Q000502:physiology*; D040901:Proteomics / Q000379:methods; D012463:Saliva / Q000201:enzymology; D018411:Spodoptera / Q000502:physiology*
chemical_list: D029681:Arabidopsis Proteins; D010940:Plant Proteins