DOI: 10.5061/dryad.905qftttk
title: Data from: Root inoculation with beneficial soil microbes enhances indirect plant defenses induced by insect feeding and egg deposition

description: 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 chromatography coupled with mass spectrometry (GC-MS) to investigate
 how root inoculation with T. harzianum T22 affects the chemical
 composition of induced plant volatiles. 3. In olfactometer assays, we
 found that root inoculation with T. harzianum T22 enhanced the attraction
 of the egg parasitoid towards tomato plants induced by N. viridula feeding
 and oviposition activities. In particular, the egg parasitoid preferred
 OIPVs emitted by tomato plants previously inoculated with T. harzianum T22
 over OIPVs emitted by non-inoculated plants. Furthermore, chemical
 analysis showed that root inoculation with T. harzianum T22 resulted in
 changes in the composition of OIPVs, which was consistent with the
 behavioral observations. Among the compounds that strongly contribute to
 the chemical differences between OIPVs from non-inoculated and inoculated
 plants, chemical analysis identified green leaf volatiles
 ((Z)-3-hepten-1-ol, (E,E)-2,4-hexadienal), along with terpenoids (terpinen
 4-ol, α-tujene and δ-elemene). 4. Taken together our results indicate that
 beneficial soil microbes enhance indirect plant defenses induced by
 feeding and oviposition, broadening our understanding of plant responses
 to insect eggs. Our results underscore the importance of taking into
 account the role of microorganisms to fully comprehend the intricate
 interactions among plants, herbivore eggs and their associated egg
 parasitoids.
description: 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".
description: # **Root inoculation with beneficial soil microbes enhances indirect plant
 defenses induced by insect feeding and egg deposition.**  [Access this
 dataset on Dryad](
 [https://doi.org/10.5061/dryad.905qftttk](https://doi.org/10.5061/dryad.905qftttk)  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 of the egg parasitoid towards tomato plants induced by *N. viridula* feeding and oviposition activities. In particular, the egg parasitoid preferred OIPVs emitted by tomato plants previously inoculated with *T. harzianum* T22 over OIPVs emitted by non-inoculated plants. Furthermore, chemical analysis showed that root inoculation with *T. harzianum* T22 resulted in changes in the composition of OIPVs, which was consistent with the behavioral observations. Among the compounds that strongly contribute to the chemical differences between OIPVs from non-inoculated and inoculated plants, chemical analysis identified green leaf volatiles ((*Z*)-3-hepten-1-ol, (*E,E*)-2,4-hexadienal), along with terpenoids (terpinen 4-ol, α-tujene and δ-elemene).  These data are used to create all of the figures and carry out the analyses presented in the manuscript.  **Description of the data and file structure**  **Raw_olfactometer.xlsx** – This file contains the data used to assess the olfactory response of *T. basalis* to volatile compounds emitted by differently treated tomato plants (Fig. 1). The values represent the residence time of *T. basalis* females in each arm of Y-tube olfactometer.  The **Raw_olfactometer.xlsx** employs the following abbreviations: -   Plant pair = tested plant pair for each set of 10 wasps. A, B, C and D indicate the plant pair replicate -   CTRL = non-inoculated and uninfested plants -   F = plants induced by *N. viridula* feeding (F) -   F_O = plants induced by *N. viridula* feeding and oviposition -   T22 – uninfested plants inoculated with *T. harzianum* T22 -   F_T22 = plants induced by *N. viridula* feeding + inoculation by *T. harzianum* T22 -   F_O_T22 = plants induced by* N. viridula* feeding and oviposition + inoculation by *T. harzianum* T22 The file contains seven sheets representing tested pair-wise combinations: 1\) Feeding *vs* Control (F vs CTRL) 2\) Feeding and Oviposition *vs* Control (F_O vs CTRL) 3\) T22 vs Control (T22 vs CTRL) 4\) Feeding + T22 vs T22 (F_T22 vs T22) 5\) Feeding and Oviposition + T22 vs T22 (F_O_T22 vs T22) 6\) Feeding + T22 vs Feeding (F_T22 vs F) 7\) Feeding and Oviposition + T22 vs Feeding and Oviposition (F_O_T22 vs F_O). Values in the columns, expressed in seconds (and 2 decimals), indicate the time spent by wasp females in each arm over an observation period of 600 s.  **Raw_volatiles.xlsx** – This file contains the data used to investigate whether differences in volatile profiles of differently treated tomato plants could explain the parasitoid behavior displayed in olfactometer bioassays (Table 1, Fig. 2). The Raw_volatiles.xlsx uses the columns: -   N = Unique ID for each chemical compound -   RT = retention time (minutes) -   LRI =* *linear retention index* *calculated using an n-alkane series (C7–C30) injected under the same conditions as samples -   compound = the name of the related chemical compound -   CTRL 1-5 = non-inoculated and uninfested plants. Numbers indicate the replicate ID -   F 1-5 = plants induced by *N. viridula* feeding (F). Numbers indicate the replicate ID -   F_O 1-4 = plants induced by *N. viridula* feeding and oviposition. Numbers indicate the replicate ID -   T22 1-5 = uninfested plants inoculated with *T. harzianum* T22. Numbers indicate the replicate ID -   F_T22 1-5 = plants induced by *N. viridula* feeding + inoculation by *T. harzianum* T22. Numbers indicate the replicate ID -   F_O_T22 1-5 = plants induced by* N. viridula* feeding and oviposition + inoculation by *T. harzianum* T22. Numbers indicate the replicate ID Amounts in the columns are reported as peak area/g fresh weight of foliage.