Rapid change in host specificity in a field population of the biological control organism Pasteuria penetrans

• Type of Material: Article
• Authors: Chang Liu, University of Georgia; Amanda Kyle Gibson, Emory University; Patricia Timper, USDA ARS; Levi T. Morran, Emory University; R. Scott Tubbs, University of Georgia
• Language: English
• Date: 2019-04-01
• Publisher: Wiley Open Access
• Publication Version: Final Published Version
• Copyright Statement: © 2018 The Authors.
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1111/eva.12750
• Title of Journal or Parent Work: Evolutionary Applications
• ISSN: 1752-4563
• Volume: 12
• Issue: 4
• Start Page: 744
• End Page: 756
• Grant/Funding Information: A.K. Gibson was supported by the NIH IRACDA program Fellowships in Research and Science Teaching (FIRST) at Emory University (K12GM000680).; C. Liu was supported by Syngenta.
• Keywords: BACILLUS-PENETRANS; EVOLUTION; LIFE-CYCLE; PLANT-PARASITIC NEMATODES; Pasteuria; peanut; LOCAL ADAPTATION; root-knot nematode; Meloidogyne; evolution of specificity; biological control; crop rotation; coevolution; Life Sciences & Biomedicine; Science & Technology; FREQUENCY-DEPENDENT SELECTION; MELOIDOGYNE-JAVANICA; Evolutionary Biology; GENETIC-VARIATION; BACTERIAL PARASITE; ROOT-KNOT NEMATODES
• Research Categories: Biology, Parasitology; Agriculture, Plant Pathology

Abstract

Evolutionary Applications published by John Wiley & Sons Ltd This article has been contributed to by US Government employees and their work is in the public domain in the USA In biological control, populations of both the biological control agent and the pest have the potential to evolve and even to coevolve. This feature marks the most powerful and unpredictable aspect of biological control strategies. In particular, evolutionary change in host specificity of the biological control agent could increase or decrease its efficacy. Here, we tested for change in host specificity in a field population of the biological control organism Pasteuria penetrans. Pasteuria penetrans is an obligate parasite of the plant parasitic nematodes Meloidogyne spp., which are major agricultural pests. From 2013 through 2016, we collected yearly samples of P. penetrans from eight plots in a field infested with M. arenaria. Plots were planted either with peanut (Arachis hypogaea) or with a rotation of peanut and soybean (Glycine max). To detect temporal change in host specificity, we tested P. penetrans samples annually for their ability to attach to (and thereby infect) four clonal lines of M. arenaria. After controlling for temporal variation in parasite abundance, we found that P. penetrans from each of the eight plots showed temporal variation in their attachment specificity to the clonal host lines. The trajectories of change in host specificity were largely unique to each plot. This result suggests that local forces, at the level of individual plots, drive change in specificity. We hypothesize that coevolution with local M. arenaria hosts may be one such force. Lastly, we observed an overall reduction in attachment rate with samples from rotation plots relative to samples from peanut plots. This result may reflect lower abundance of P. penetrans under crop rotation, potentially due to suppressed density of host nematodes. As a whole, the results show local change in specificity on a yearly basis, consistent with evolution of a biological control organism in its ability to infect and suppress its target pest.