Location: Fruit and Tree Nut ResearchTitle: Infected host responses across entomopathogenic nematode phylogeny
|ERDOGAN, HILAL - Uludag University|
|STEVENS, GLEN - University Of Idaho|
|STEVENS, ASA - University Of Idaho|
|Shapiro Ilan, David|
|KAPLAN, FATMA - Pheronym, Inc|
|LEWIS, EDWIN - University Of Idaho|
Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/23/2021
Publication Date: 3/30/2022
Citation: Erdogan, H., Stevens, G., Stevens, A., Shapiro Ilan, D.I., Kaplan, F., Alborn, H.T., Lewis, E.E. 2022. Infected host responses across entomopathogenic nematode phylogeny. Journal of Nematology. 53,e2021-105. https://doi.org/10.21307/jofnem-2021-105.
Interpretive Summary: Nematodes are simple round worms. Entomopathogenic nematodes, also called beneficial nematodes, kill insesct pests; they are environmentally-friendly bioinsecticides. We are studying how these beneficial nematodes move through soil and find their insect hosts to attack. Previously, for certain nematode species, we discovered that compounds released from the dead infected insects send signals to other nematodes to increase dispersal and infection. In the present study, we compared the response to these chemical signals across five species of nematodes. Only three of the five nematode species responded to infected host signals produced by the same nematode species. Furthermore, nematodes generally did not respond to host signals produced by other nematode species. These findings indicate that beneficial nematode dispersal behavior based on signaling compounds is complex and variable. Understanding the mechanisms for beneficial nematode movement and infection behavior will enable us to leverage this knowledge to increase efficacy in biological pest control.
Technical Abstract: We used a phylogenetic framework to examine the relationship between entomopathogenic nematode (EPN) vertical dispersal and infectivity when EPN are exposed to a mixture of compounds found in late-stage EPN-infected insect cadavers. EPN from 5 phylogenetically related and distant species (H. bacteriophora, H. georgiana, H. megidis, H. indica and Steinernema feltiae) were exposed to macerate produced by their own species’ infection and by H. bacteriophora infected hosts. While prior work has suggested consistent stimulation of dispersal on exposure to macerate, we found that only 3 of the 5 species (H. bacteriophora, H. indica and S. feltiae) responded to exposure to their own macerate by increasing rates of dispersal and infectivity. When we exposed all 5 species to a H. bacteriophora infected host macerate, we found that only H. bacteriophora responded by increasing dispersal, and that the most distantly related species (S. feltiae) essentially halted dispersal when exposed to H. bacteriophora-derived macerate. These findings suggest that (1) responses to host macerate vary (2) the balance between cues and signals in the macerate masks otherwise clear cross-species signals, and (3) there may be a relationship between inherent dispersal rates and sensitivity to macerate exposure, as the most rapidly dispersing species (H. megidis) showed no response to macerate exposure.