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The dual effects of root-cap exudates on nematodes: from quiescence in plant-parasitic nematodes to frenzy in entomopathogenic nematodes.

Hiltpold I, Jaffuel G, Turlings TC - J. Exp. Bot. (2014)

Bottom Line: Notably, after storage in root exudate, EPN performance traits were maintained over time, whereas performances of EPNs stored in water rapidly declined.In sharp contrast to high concentrations, lower concentrations of the exudate resulted in a significant increase in EPN activity and infectiousness, but still reduced the activity of two plant-parasitic nematode species.Appropriately formulated, it can favour long-term storage of EPNs and boost their infectiousness, while it may also be used to protect plants from plant-parasitic nematodes.

View Article: PubMed Central - PubMed

Affiliation: Division of Plant Sciences, University of Missouri, 205 Curtis Hall, Columbia, MO 65211-7020, USA hiltpoldi@missouri.edu.

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Low root-exudate concentration has a dual effect on nematode activity. (A) The number of oscillations per minute was significantly increased when the EPN Heterorhabditis bacteriophora was exposed to 1.5×-diluted exudates (grey bar) as compared to those in water (white bar). The original (1×) concentration of exudate induced almost complete quiescence in the exposed EPN. (B) The plant-parasitic nematode Heterodera glycine oscillation counts were higher in diluted exudate as compared to the original concentration. Whereas quiescence induction was incomplete at low concentration, the plant-parasitic nematode oscillation activity was still almost 3-fold lower than observed in water alone. (C) A similar pattern was observed for the plant-parasitic nematode Meloidogyne incognita. Letters indicate statistical differences. Bars indicate SEM.
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Figure 4: Low root-exudate concentration has a dual effect on nematode activity. (A) The number of oscillations per minute was significantly increased when the EPN Heterorhabditis bacteriophora was exposed to 1.5×-diluted exudates (grey bar) as compared to those in water (white bar). The original (1×) concentration of exudate induced almost complete quiescence in the exposed EPN. (B) The plant-parasitic nematode Heterodera glycine oscillation counts were higher in diluted exudate as compared to the original concentration. Whereas quiescence induction was incomplete at low concentration, the plant-parasitic nematode oscillation activity was still almost 3-fold lower than observed in water alone. (C) A similar pattern was observed for the plant-parasitic nematode Meloidogyne incognita. Letters indicate statistical differences. Bars indicate SEM.

Mentions: Reducing the exudate concentration quickly reached a threshold beyond which induction of quiescence in H. bacteriophora failed (Fig. 3; ANOVA on ranks, H7,15 = 52.42, P ≤ 0.001), but instead resulted in increased movement (Fig. 4A; ANOVA, F2–89 = 491.427, P ≤ 0.001). At a low concentration, the exudate had a positive impact on the infectiousness of H. bacteriophora (Fig. 5; RM two-way ANOVA, F1,107 = 20.991, P = 0.006), and EPN exposed to low concentration exudates were more effective at killing G. mellonella over time as compared to EPN exposed to water only (Fig. 5; RM two-way ANOVA, F8,107 = 5.88, P ≤ 0.001). Contrary to the effect on EPNs, the same low concentration of exudate significantly reduced the mobility of the tested plant-parasitic nematode species H. glycine (Fig. 4B; ANOVA, F2–89 = 225.023, P ≤ 0.001) and M. incognita (Fig. 4C; ANOVA on ranks, H = 67.876, P ≤ 0.001).


The dual effects of root-cap exudates on nematodes: from quiescence in plant-parasitic nematodes to frenzy in entomopathogenic nematodes.

Hiltpold I, Jaffuel G, Turlings TC - J. Exp. Bot. (2014)

Low root-exudate concentration has a dual effect on nematode activity. (A) The number of oscillations per minute was significantly increased when the EPN Heterorhabditis bacteriophora was exposed to 1.5×-diluted exudates (grey bar) as compared to those in water (white bar). The original (1×) concentration of exudate induced almost complete quiescence in the exposed EPN. (B) The plant-parasitic nematode Heterodera glycine oscillation counts were higher in diluted exudate as compared to the original concentration. Whereas quiescence induction was incomplete at low concentration, the plant-parasitic nematode oscillation activity was still almost 3-fold lower than observed in water alone. (C) A similar pattern was observed for the plant-parasitic nematode Meloidogyne incognita. Letters indicate statistical differences. Bars indicate SEM.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4286403&req=5

Figure 4: Low root-exudate concentration has a dual effect on nematode activity. (A) The number of oscillations per minute was significantly increased when the EPN Heterorhabditis bacteriophora was exposed to 1.5×-diluted exudates (grey bar) as compared to those in water (white bar). The original (1×) concentration of exudate induced almost complete quiescence in the exposed EPN. (B) The plant-parasitic nematode Heterodera glycine oscillation counts were higher in diluted exudate as compared to the original concentration. Whereas quiescence induction was incomplete at low concentration, the plant-parasitic nematode oscillation activity was still almost 3-fold lower than observed in water alone. (C) A similar pattern was observed for the plant-parasitic nematode Meloidogyne incognita. Letters indicate statistical differences. Bars indicate SEM.
Mentions: Reducing the exudate concentration quickly reached a threshold beyond which induction of quiescence in H. bacteriophora failed (Fig. 3; ANOVA on ranks, H7,15 = 52.42, P ≤ 0.001), but instead resulted in increased movement (Fig. 4A; ANOVA, F2–89 = 491.427, P ≤ 0.001). At a low concentration, the exudate had a positive impact on the infectiousness of H. bacteriophora (Fig. 5; RM two-way ANOVA, F1,107 = 20.991, P = 0.006), and EPN exposed to low concentration exudates were more effective at killing G. mellonella over time as compared to EPN exposed to water only (Fig. 5; RM two-way ANOVA, F8,107 = 5.88, P ≤ 0.001). Contrary to the effect on EPNs, the same low concentration of exudate significantly reduced the mobility of the tested plant-parasitic nematode species H. glycine (Fig. 4B; ANOVA, F2–89 = 225.023, P ≤ 0.001) and M. incognita (Fig. 4C; ANOVA on ranks, H = 67.876, P ≤ 0.001).

Bottom Line: Notably, after storage in root exudate, EPN performance traits were maintained over time, whereas performances of EPNs stored in water rapidly declined.In sharp contrast to high concentrations, lower concentrations of the exudate resulted in a significant increase in EPN activity and infectiousness, but still reduced the activity of two plant-parasitic nematode species.Appropriately formulated, it can favour long-term storage of EPNs and boost their infectiousness, while it may also be used to protect plants from plant-parasitic nematodes.

View Article: PubMed Central - PubMed

Affiliation: Division of Plant Sciences, University of Missouri, 205 Curtis Hall, Columbia, MO 65211-7020, USA hiltpoldi@missouri.edu.

Show MeSH
Related in: MedlinePlus