Proteomic analysis of labial saliva of the generalist cabbage looper (Trichoplusia ni) and its role in interactions with host plants. (May 2018)

• Record Type: Journal Article
• Authors: Rivera-Vega, Loren J.; Stanley, Bruce A.; Stanley, Anne; Felton, Gary W.
• Is Part Of: Journal of insect physiology. Volume 107(2018)
• Page Start: 97
• Page End: 103
• Publication Date: 2018-05
• Subjects: ITraq -- Plasticity -- Herbivore offense -- Catalase -- Detoxification -- Reactive oxygen species -- Antioxidant; Insects -- Physiology -- Periodicals; Insectes -- Physiologie -- Périodiques; Insects -- Physiology; Periodicals; 571.157
• DOI: 10.1016/j.jinsphys.2018.03.001
• Languages: English
• ISSNs: 0022-1910

Abstract

Graphical abstract: Highlights: We identified 254 proteins in the saliva of Trichoplusia ni . Host plant has an effect on Trichoplusia ni saliva composition. Antioxidants and ROS scavengers were identified in the saliva of Trichoplusia ni . Trichoplusia ni saliva contains catalase activity. Catalase application on tomato plants suppresses trypsin proteinase inhibitors. Abstract: Insect saliva is one of the first secretions to come in contact with plants during feeding. The composition and role of caterpillar saliva has not been as thoroughly studied as that of sucking insects. This study focuses on characterizing the proteome of the cabbage looper ( Trichoplusia ni ) saliva using iTRAQ labeling and LC-MS/MS. We also measured how the saliva proteome changed when larvae were reared on different diets – cabbage, tomato, and an artificial pinto bean diet. We identified 254 proteins in the saliva out of which 63 were differentially expressed. A large percentage (56%) of the proteins identified function in protein metabolism, followed by proteins involved in vesicle transport (6%) and oxidoreductase activity (5%), among other categories. Several proteins identified are antioxidants or reactive oxygen species (ROS) scavengers. Among these ROS scavengers, we identified a catalase and further analyzed its gene expression and enzymatic activity. We also applied commercial, purified catalase on tomato and measured the activity of defensive proteins – trypsin proteinase inhibitor, polyphenol oxidase and peroxidase. Catalase gene expression was significantly higher in the salivary glands of larvae fed on tomato. Also, catalase suppressed the induction of tomato trypsin proteinase inhibitor levels, but not the induction of polyphenol oxidase or peroxidase. These results add to our understanding of proteomic plasticity in saliva and its role in herbivore offense against plant defenses.