Data from: Root inoculation with beneficial soil microbes enhances indirect plant defenses induced by insect feeding and egg deposition
Data files
May 09, 2024 version files 44.73 KB
Abstract
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.
README: 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 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.
Methods
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".