Plant-associated CO2 mediates long-distance host location and foraging behaviour of a root herbivore
- Institute of Biology, University of Neuchâtel, Switzerland
- Institute of Plant Sciences, University of Bern, Switzerland
Figures
Figure 1
Plants create CO2 gradients in the soil.
(A, B) CO2 levels were determined in soil-filled trays at different distances from young maize seedlings (A) before and (B) after removing the seedlings from the system. Arrows indicate air sampling …
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Figure 1—source data 1
Raw data for Figure 1.
- https://cdn.elifesciences.org/articles/65575/elife-65575-fig1-data1-v1.xlsx
Figure 2
The western corn rootworm (WCR) genome contains three putative carbon dioxide (CO2) receptors.
(A) Phylogenetic relationships between putative CO2 receptors based on protein sequences of different insects. Dmel: Drosophila melanogaster; Dsim: Drosophila simulans; Dsec: Drosophila sechellia; …
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Figure 2—source data 1
Raw data for Figure 2.
- https://cdn.elifesciences.org/articles/65575/elife-65575-fig2-data1-v1.xlsx
Figure 3 with 1 supplement
The carbon dioxide group 2 receptor (DvvGr2) is specifically required for the attraction of western corn rootworm (WCR) towards CO2.
(A) Mean (± SEM) relative gene expression levels of group 1 (DvvGr1), group 2 (DvvGr2), and group 3 (DvvGr3) CO2 receptors after WCR larvae were fed with dsRNA-expressing bacteria targeting green …
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Figure 3—source data 1
Raw data for Figure 3.
- https://cdn.elifesciences.org/articles/65575/elife-65575-fig3-data1-v1.xlsx
Figure 3—figure supplement 1
Carbon dioxide levels at different sampling points.
Mean (± SEM) CO2 levels in each olfactometer side and in the air (n = 3–4). Different letters indicate significant differences in CO2 levels (p < 0.05 by one-way ANOVA with Holm’s …
Figure 4 with 1 supplement
DvvGr2 is required for dose-dependent western corn rootworm (WCR) responses to CO2.
(A) Two-arm olfactometer used to test the attractive and repellent effects of CO2 on WCR larvae. (B) Mean ( ± SEM) proportion of WCR larvae observed in each arm of the olfactometers. Larvae were …
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Figure 4—source data 1
Raw data for Figure 4.
- https://cdn.elifesciences.org/articles/65575/elife-65575-fig4-data1-v1.xlsx
Figure 4—figure supplement 1
Carbon dioxide levels at different sampling points.
Mean (± SEM) CO2 levels in olfactometer sides that were treated with air or with CO2-enriched synthetic air (n = 3). Asterisks indicate significant differences in CO2 levels (*p < 0.05; **p < 0.01; …
Figure 5
Silencing the carbon dioxide group 2 receptor (DvvGr2) impairs western corn rootworm (WCR) responses to CO2 without affecting larval motility or search behaviour.
(A, B) Trajectories of individual wild type (WT) (A) and DvvGr2-silenced (B) WCR larvae in Petri plates with a CO2 source. The blue circles represent larval release points. The red circles represent …
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Figure 5—source data 1
Raw data for Figure 5.
- https://cdn.elifesciences.org/articles/65575/elife-65575-fig5-data1-v1.xlsx
Figure 6 with 2 supplements
Plant-associated CO2 mediates host location by western corn rootworm (WCR) larvae in a distance-specific manner.
(A, B) Mean (± SEM) proportion (%) of WCR larvae observed on each side of the olfactometers. Larva were considered to have made a choice when they were found at a distance of 1 cm or less from the …
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Figure 6—source data 1
Raw data for Figure 6.
- https://cdn.elifesciences.org/articles/65575/elife-65575-fig6-data1-v1.xlsx
Figure 6—figure supplement 1
Carbon dioxide levels at different sampling points.
Mean (± SEM) CO2 levels in olfactometer sides with or without plants (n = 4). Asterisks indicate significant differences in CO2 levels (***p < 0.001 by generalized linear model [GLM] followed by …
Figure 6—figure supplement 2
Soda lime does not influence the diffusion of plant volatiles other than CO2 into olfactometer arms.
(A) Representative chromatograms of volatiles from maize roots in the absence (control, blue chromatogram) or the presence of a soda lime layer that removes CO2 (soda lime, orange chromatogram). (B) …
Figure 7 with 2 supplements
Root-associated CO2 is used by western corn rootworm (WCR) larvae for host location in a distance-specific manner.
(A) Mean (± SEM) proportion of wild type (WT) (dark green) or DvvGr2-silenced (light green) WCR larvae observed in the different tray zones 8 hr after releasing the larvae in the centre of …
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Figure 7—source data 1
Raw data for Figure 7.
- https://cdn.elifesciences.org/articles/65575/elife-65575-fig7-data1-v1.xlsx
Figure 7—figure supplement 1
Carbon dioxide levels at different sampling points.
Mean (± SEM) CO2 levels detected in the soil gas phase of each tray zone or in the air (n = 3–4). Different letters indicate significant differences in CO2 levels (p < 0.05 by one-way ANOVA with …
Figure 7—figure supplement 2
Root-associated CO2 is required for host location by western corn rootworm (WCR) larvae at long distances.
(A) Schematic representation (photomontage) of experimental set-up used. (B) Mean (± SEM) proportion of WCR larvae retrieved at close vicinity of root systems (i.e., on root barriers). Twenty-five …
Figure 8 with 1 supplement
CO2 perception increases the location of more suitable host plants.
(A, B) Schematic representation (photomontage) of soil-filled trays used to evaluate location of differentially fertilized plants by western corn rootworm (WCR) larvae depicting mean (± SEM) CO2 …
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Figure 8—source data 1
Raw data for Figure 8.
- https://cdn.elifesciences.org/articles/65575/elife-65575-fig8-data1-v1.xlsx
Figure 8—figure supplement 1
Carbon dioxide levels at different sampling points.
(A, B) Mean (± SEM) CO2 levels detected in the soil gas phase of each tray zone (n = 10). Different letters indicate statistically significant differences in CO2 levels (p < 0.05 by one-way ANOVA …
Additional files
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Supplementary file 1
Description and results of the statistical analysis methods used to analyse the data of this study.
- https://cdn.elifesciences.org/articles/65575/elife-65575-supp1-v1.xlsx
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Transparent reporting form
- https://cdn.elifesciences.org/articles/65575/elife-65575-transrepform-v1.docx
