Epichloë endophytes impair performance and preference of Rhopalosiphum padi by disrupting aphid feeding behaviour in tall fescue
Data files
Dec 18, 2025 version files 49.45 KB
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ANTIBIOSIS_IND.csv
2.81 KB
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ANTIXENOSIS_POP.csv
7.89 KB
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ANTXENOSIS_IND.csv
9.49 KB
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EPG_.csv
15.43 KB
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README.md
13.83 KB
Abstract
Mutualistic symbioses between plants and fungi are widespread in nature and are increasingly being adopted in agroecosystems to enhance economic and environmental sustainability. Temperate forage grasses often associate with Epichloë endophytic fungi that, by hindering herbivore performance, confer protection against insect damage, aphids in particular. However, despite the well-known impacts of endophytes on aphid preference and performance, there is scant information on how such effects are caused by alterations in feeding behaviour. The main objective here was to explore interactions between a grass plant, its fungal endophyte, and aphids, focusing on using the Electrical Penetration Graph technique to understand in detail the various aspects of aphid feeding behavior. Experiments were conducted in a greenhouse with tall fescue cultivars INIA Aurora and INIA Fortuna, grown with (+) or without (-) the AR584-Epichloë strain of Epichloë coenophiala, and exposed to bird-cherry oat aphids, Rhopalosiphum padi. Aphid performance was evaluated in antibiosis tests (no choice), at both population and individual levels, and preference in antixenosis (choice) tests. Aphid feeding behaviour was studied using the Electrical Penetration Graph technique in both seedlings and adult plants. Daily fecundity and aphid population growth were both lower on endophytic plants, indicating a preference for endophyte-free plants. Aphids exhibited impaired feeding behaviour on endophytic plants, with shorter phloem activities. Similar patterns were observed in seedlings. These results demonstrate that endophytes negatively affect aphid phloem sap ingestion, explaining the subsequent insecticidal and antifeedant effects, and that these can explain the ulterior insecticidal and antifeedant consequences.
Dataset DOI: 10.5061/dryad.wdbrv163c
Description of the data and file structure
Figure 1: Population Experiments
- Fig. 1A — from file:
ANTIBIOSIS POP - Fig. 1B — from file:
ANTIXENSOSIS- These contain population-level data for antibiosis and antixenosis, respectively.
Figure 1: Individual Experiments
- Fig. 1C — from file:
ANTIBIOSIS IND - Fig. 1D — from file:
ANTIXENSOSIS IND- These contain individual-level data for the same traits.
EPG Data
- File:
EPG DATA SET- This file includes all variables related to EPG (Electrical Penetration Graph) recordings — likely insect feeding behavior variables.
Files and variables
File: ANTIBIOSIS_IND.csv
Description: these contain individual-level data for the antibiosis (no-cice) exp.
Variables
- POT: experimental unit
- VAR: pant variety
- DAYTA: days to adult
- NYMPHS/D: average number of nymphs deposited
File: EPG_.csv
Description: This file includes all variables related to EPG (Electrical Penetration Graph) recordings — likely insect feeding behavior variables.
Variables
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Origin: posoition within EPG
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plant: endophytic status of plant
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Exp_time: days
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n_Np: number of non probing periods
EPG-TABLE NAME EXPLANATION n_Np number of non probing periods a_Np average non probing (period duration) m_Np median non probing (period duration) s_Np sum of non probing n_Pr number of probes n_bPr number of brief probes (probes < 180 s) a_Pr average probe m_Pr median probe s_Pr sum of probing n_C number of C periods a_C average C; with pd without E1e, F and G m_C median C s_C sum of C n_F number of F a_F average F m_F median F s_F sum of F n_G number of G a_G average G m_G median G s_G sum of G t_1G time to the first G (after first penetration) nPr_1G number of probes before the first G n_E1e number of E1 extracellular (E1e) periods a_E1e average E1e m_E1e median E1e s_E1e sum of E1e n_sgE1 number of single E1 (without E2) periods a_sgE1 average single E1 m_sgE1 median single E1 s_sgE1 sum of single E1 mx_sgE1 maximum duration of a single E1 period n_frE1 number of fractions of E1;: E1followed/preceded by E2 a_frE1 average fraction of E1 m_frE1 median fraction of E1 s_frE1 sum of fractions of E1 mx_frE1 maximum duration of a fraction of E1 n_E1 number of all E1 periods (sgE1 + frE1) a_E1 average E1 m_E1 median E1 (sgE1 and E1fr) s_E1 sum of E1 (sgE1 and E1) mx_E1 maximum E1 period (either sgE1 or frE1) n_E12 number of E12 phloem periods i.e. with both, E1 and E2 a_E12 average E12 m_E12 median E12 (with both E1 and/or E2) s_E12 sum of E12 mx_E12 maximum E12, phloem phase with E1 and/or E2 n_E2 number of E2 periods a_E2 average E2 m_E2 median E2 s_E2 sum of E2 mx_E2 maximum E2 period n_sE2 number of sustained E2 (sustained E2, i.e. E2 longer than 10 min) a_sE2 mean duration of sE2 m_sgE2 median duration of sE2 s_sE2 sum of duration of sE2 t_1Pr time to 1st probe (in recording; = d_1Np) d_1Pr duration of 1st probe t_1E time to 1st E (always E1; from the 1st probe) t_C_1E_1Pr time to 1st E within the 1st probe with E at_C_1E_Pr average time to 1st E within probes mn_C_1E_Pr minimum time to 1st E within probes n_bPr_1E number of brief probes < 3 min before 1st E n_Pr_1E number of probes before the 1st E t_1E12 time to 1st E12 t_1E2 time to 1st E2 t_1sE2 time to 1st sE2 (E2 > 10 min) n_Pr_1E2 number of probes to the 1st E2 (=E2 in 1stE12) n_Pr_1sE2 number of probes before 1st sE2 nPr_1sE2 number of probes after 1st sE2 n_E2_1sE2 number of E2 before the 1st sE2 t_1E1_1E2 time from the 1st E1 to 1st E2 t_1E1_1sE2 time from the 1st E1 to 1st sustainable E2 s_E1_1sE2 sum of E1 before 1st sE2 s_E2_1sE2 sum of E2 before 1st sE2 a_E2_1sE2 mean duration of E2 periods before the 1st sE2 rel_E2_C SE ingestion/pathway ratio as % rel_E1_allE E1 index:duration E1/ allE as % n_frE1_n_E12 phloem phase fractioning rel_E2_1E2 E2 index: % (all time of E2 / Time to the start of 1st E2 from first penetration) n_pd number of pd a_pd average duration of pd m_pd median duration of pd s_pd sum of pd a_pd_II_1 average pd2_1 duration m_pd_II_1 median pd2_1 duration s_pd_II_1 sum of pd2_1 periods a_pd_II_2 average pd2_2 duration m_pd_II_2 median pd2_2 duration s_pd_II_2 sum of pd2_2 periods a_pd_II_3 average pd2_3 duration m_pd_II_3 median pd2_3 duration s_pd_II_3 sum of pd2_3 periods t_1pd time to 1st pd (from start of 1st probe) t_1pd_1pr time to 1st pd in 1st probe with a pd at_1pd_Pr average time to 1st pd in all probes with a pd mt_1pd_Pr median time to 1st pd in all probes with a pd mnt_1pd_1Pr min. time to 1st pd in 1st probe n_pd_minC no. pd per min C n_pd_minC_pd no. pd per min C , only C_phases with pd n_pd_1Pr no. pd in 1st probe rel_Prob_pd relation of probes with pd n_Pr_1pd number of probes before 1st pd d_1pd duration of the first pd d_2pd duration of the second pd d_pd5 mean duration of the first 5 pd s_pdII-3_5pd sum of subphase 3 of the first 5 pd
File: ANTIXENOSIS_POP.csv
Description: These contain population-level data for antixenosis (chocie) exp
Variables
- CUAD: square
- VAR: variety
- DATE : calendar date
- ALATE: # alate aphid form
- APTEROUS: # apterous aphid form
- NYMPHS :# nymphs aphid form
- TOTAL : sum of aphids
- HEIGHT: plant height in cm
- TILLER: tiller number
- TEF: tiller weight (mg)
- SCORE: damage score
- DRY.W: plant dry weight (mg)
File: ANTXENOSIS_IND.csv
Description: These contain individual-level data for the antibiosis (choice) exp.
Variables
- DATE: DATE
- CUP: experimental unit
- VAR1/VAR2: varietes within the capsule (1 and 2; fig 1 D)
- VAR1: variety 1 ; fig 1 D
- VAR2: variety 2 ; fig 1 D
All data from both the no-choice (antibiosis) and choice (antixenosis) experiments, including aphid population and individual responses, were analysed using mixed model ANOVA (PROC MIXED, SAS 2009). Normality assumptions were assessed using the Shapiro-Wilk test statistic (PROC UNIVARIATE, SAS 2009). The models examined the main effects of cultivar (four populations and five individuals), with individual seedlings or plants treated as random factors. Pairwise comparisons between cultivars were conducted using least-squares means (LS MEANS statement), with means separated using an adjusted Tukey method for multiple comparisons (α = 0.05). Mean differences were compared using the least-squares mean difference (LSD) from an adjusted Fisher’s protected LSD method for multiple comparisons (α = 0.05). Additionally, a Pearson rank correlation coefficient test was used to analyse the relationship between plant dry mass and plant height, specifically in plants inoculated with aphids or those that remained aphid-free during the aphid population experiment.
Results from EPG measurements did not exhibit a normal distribution (Table 3, variables 1–8, 10–11, 13–22). Therefore, Mann–Whitney U rank sum tests were employed to assess differences in aphid feeding behaviour between plants with different endophytic status. Fisher’s exact test was used to evaluate disparities in the proportions of individuals engaging in specific types of activity between plants with different endophytic status (Table 3, variables 9, 12, 15, 23, and 24). Significance levels were adjusted for multiple testing using the false discovery rate (FDR) correction method at α = 0.05 (Benjamini and Hochberg 1995). A comprehensive description of the FDR procedure is provided in Benjamini et al. (2001). All statistical analyses for these experiments were conducted using InfoStat Professional v2011p software (Di Rienzo et al. 2013).