Interactions between insect vectors and plant pathogens span the parasitism–mutualism continuum

Abstract

Agricultural crops infected with vector-borne pathogens can suffer severe negative consequences, but the extent to which phytopathogens affect the fitness of their vector hosts remains unclear. Evolutionary theory predicts that selection on vector-borne pathogens will favour low virulence or mutualistic phenotypes in the vector, traits facilitating effective transmission between plant hosts. Here, we use a multivariate meta-analytic approach on 115 effect sizes across 34 unique plant–vector–pathogen systems to quantify the overall effect of phytopathogens on vector host fitness. In support of theoretical models, we report that phytopathogens overall have a neutral fitness effect on vector hosts. However, the range of fitness outcomes is diverse and span the parasitism–mutualism continuum. We found no evidence that various transmission strategies, or direct effects and indirect (plant-mediated) effects, of phytopathogens have divergent fitness outcomes for the vector. Our finding emphasizes diversity in tripartite interactions and the necessity for pathosystem-specific approaches to vector control.

Differential gene expression in the insect vector Anasa tristis in response to symbiont colonization but not infection with a vectored phytopathogen

“…Mounting an immune response can be energetically costly for the insect host (Ardia et al, 2012), and in the case of vectored pathogens, evolution toward reduced antagonism would favor longer host infection times and could contribute to higher transmission success. As a whole, there is broad evidence for a net neutral effect of vectored pathogens on their vectors (Santiago et al, 2023). The lack of transcriptional differences between S. marcescens infected and uninfected insects that we observed suggests that this may be the case for A. tristis as well.…”

Leveraging Biotic Interaction Knowledge Graph and Network Analysis to Uncover Insect Vectors of Plant Virus

“…The testing stage aims to validate network analysis methods. Test data, consisting of 21 pairs of viruses and their confirmed insect vectors from [3,[39][40][41], can be accessed at https://linktr.ee/vektorpedia. The precision metric [42] is used to assess the accuracy of predicting the taxon paths of the actual insect vectors.…”

Fusarium phytopathogens as insect mutualists

“…Due to their ecological diversity and their herbivorous habits, insects are important vectors of many plant diseases [ 31 ]. Vector-borne pathogens are predicted to (i) increase their dissemination by manipulating insect behavior and (ii) evolve to be less virulent to its vector over evolutionary time [ 31 ].…”

“…Due to their ecological diversity and their herbivorous habits, insects are important vectors of many plant diseases [ 31 ]. Vector-borne pathogens are predicted to (i) increase their dissemination by manipulating insect behavior and (ii) evolve to be less virulent to its vector over evolutionary time [ 31 ]. While the benefits insects derive from their fusarial partners are diverse, spanning nutrition to defense, the benefit of associating with an insect for the microbial partner is conserved: propagation to naïve plants, thereby expanding their ecological range.…”