Phytohormone?dependent plant defense signaling orchestrated by oral bacteria of the herbivore <i>Spodoptera litura</i>

A vast array of herbivorous arthropods live with symbiotic microorganisms. However, little is known about the nature and functional mechanism bacterial effects on plant defense responses towards herbivores. We explored role microbes present in extracts oral secretion (OS) isolated from larvae Spodoptera litura, a generalist herbivore, phytohormone signaling-dependent Arabidopsis thaliana (Arabidopsis). In response to mechanical damage (MD) application bacteria-free OS (OS–) prepared by sterilization or filtration OS, leaves exhibited enhanced de novo synthesis oxylipins, induction transcript abundance responsible genes, comparison those MD + nonsterilized (OS+), indicating that bacteria serve as suppressors these genes. By contrast, synthesis/signaling salicylic acid signaling abscisic were bacteria. These networks cross-regulated each other. Meta-analysis identified 70 strains. Among them was Staphylococcus epidermidis, an anaerobic staphylococcus shown contribute suppression/manipulation phytohormone-dependent signaling. The presence consequently beneficial for S. litura hosted Brassicaceae.