Root inoculation with beneficial soil microbes enhances indirect plant defenses induced by insect feeding and egg deposition

Plants can respond to insect egg deposition by emitting oviposition-induced plant volatiles (OIPVs) recruiting parasitoids. The recruitment of carnivore insects in response to egg deposition is considered an indirect defense strategy that is widespread in the plant kingdom. In recent years, there has been increasing evidence showing that microbial colonization can influence the strength of plant responses to insect herbivory, yet no information is available on how beneficial microbes modulate indirect defenses induced by insect egg deposition. In this work, we evaluated the effects of inoculation with the beneficial soil fungus Trichoderma harzianum strain T22 on a tritrophic system consisting of tomato, the southern green stink bug Nezara viridula and its associated egg parasitoid Trissolcus basalis. We used Y-tube olfactometer assays to evaluate the behavioral responses of the parasitoids to OIPVs emitted by plants colonized with beneficial soil microbes. We also used gas chromatograp...,
Exhaustive information about dataset collection and processing can be found on the M&M section of the associated manuscript (FE-2024-00039) published in \"Functional Ecology\".
, , # **Root inoculation with beneficial soil microbes enhances indirect plant defenses induced by insect feeding and egg deposition.**

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 We evaluated the effects of inoculation with the beneficial soil fungus *Trichoderma harzianum* strain T22 on a tritrophic system consisting of tomato, the southern green stink bug *Nezara viridula* and its associated egg parasitoid *Trissolcus basalis*. We used Y-tube olfactometer assays to evaluate the behavioral responses of the parasitoids to oviposition-induced plant volatiles (OIPVs) emitted by plants colonized with beneficial soil microbes. We also used gas chromatography coupled with mass spectrometry (GC-MS) to investigate how root inoculation with *T. harzianum* T22 affects the chemical composition of induced plant volatiles.

 In olfactometer assays, we found that root inoculation with *T. harzianum* T22 enhanced the attraction o...