Avirulence gene mapping in the Hessian fly (Mayetiola destructor) reveals a protein phosphatase 2C effector gene family

Abstract

The genetic tractability of the Hessian fly (HF, Mayetiola destructor) provides an opportunity to investigate the mechanisms insects use to induce plant gall formation. Here we demonstrate that capacity using the newly sequenced HF genome by identifying the gene (vH24) that elicits effector-triggered immunity in wheat (Triticum spp.) seedlings carrying HF resistance gene H24. vH24 was mapped within a 230-kb genomic fragment near the telomere of HF chromosome X1. That fragment contains only 21 putative genes. The best candidate vH24 gene in this region encodes a protein containing a secretion signal and a type-2 serine/threonine protein phosphatase (PP2C) domain. This gene has an H24-virulence associated insertion in its promoter that appears to silence transcription of the gene in H24-virulent larvae. Candidate vH24 is a member of a small family of genes that encode secretion signals and PP2C domains. It belongs to the fraction of genes in the HF genome previously predicted to encode effector proteins. Because PP2C proteins are not normally secreted, our results suggest that these are PP2C effectors that HF larvae inject into wheat cells to redirect, or interfere, with wheat signal transduction pathways.

Pseudomonas syringae enhances herbivory by suppressing the reactive oxygen burst in Arabidopsis

“…proteinaceous effectors, phytohormones or phytohormone analogs secreted with the saliva) with those offered by microbes, as has been observed in other plant-herbivore and plant-plant parasitic nematode interactions (e.g. Favery et al, this issue; Guiguet et al, this issue; Harris et al, 2015; Kazan and Lyons, 2014; Zhang et al, this issue; Zhao et al, this issue). Future field-based experiments such as those described by Humphrey et al (2014) and O’Connor et al (2014) will allow us to gauge the extent and relevance of these associations.…”

Proteins Identified from Saliva and Salivary Glands of the Chinese Gall Aphid Schlechtendalia chinensis

“…It is very likely that some of aphid saliva proteins play a role in gall induction in addition to other functions common to free‐living aphids. In gall midges, a huge number of putative effector proteins are likely delivered into host tissues for host manipulation and gall induction . The most striking characteristic for putative gall midge effectors is a large number of highly diversified, small peptides.…”

Genes Expressed Differentially in Hessian Fly Larvae Feeding in Resistant and Susceptible Plants

“…However, several lines of evidence suggest that Hessian fly R genes share structural similarity with plant disease R genes and belong to the super-group of receptor-like kinases which possess a nucleotide binding site and leucine zip repeats. Two Hessian fly Avr genes have been cloned and characterized [7,8]. These Avr genes encode secreted proteins that are likely injected into plant tissue through saliva during feeding.…”