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ARS Home » Pacific West Area » Wapato, Washington » Temperate Tree Fruit and Vegetable Research » Research » Publications at this Location » Publication #415728
Research Project: Integrated Approach to Manage the Pest Complex on Temperate Tree Fruits

Location: Temperate Tree Fruit and Vegetable Research

Title: Gene expression profiling of Cacopsylla pyricola (Hemiptera: Psyllidae) infected with Ca. Phytoplasma pyri (Acholeplasmatales: Acholeplasmataceae) reveals candidate effectors and mechanisms of infection

Author
item Easterling, Katherine
item Marshall, Adrian
item Pitino, Marco
item Walker, William
item Cooper, William - Rodney

Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/20/2024
Publication Date: 9/5/2024
Citation: Easterling, K.A., Marshall, A.T., Pitino, M., Walker Iii, W.B., Cooper, W.R. 2024. Gene expression profiling of Cacopsylla pyricola (Hemiptera: Psyllidae) infected with Ca. Phytoplasma pyri (Acholeplasmatales: Acholeplasmataceae) reveals candidate effectors and mechanisms of infection. Environmental Entomology. https://doi.org/10.1093/ee/nvae074.
DOI: https://doi.org/10.1093/ee/nvae074

Interpretive Summary: “Candidatus Phytoplasma pyri”, is the causal agent of pear decline in commercial pear (Pyrus communis) and peach yellow leafroll in peach (Prunus persica). This plant pathogen is transmitted by several species of pear psyllids. We sought to explore the relationship between the pear decline phytoplasma and its U.S. vector, Cacopsylla pyricola, at the molecular genetic level. We examined gene expression differences in C. pyricola insects that were either infected or not infected with phytoplasma in order to better understand mechanisms of infection and insect responses to a pathogen that can be devastating to pear crops. Currently, pear breeding programs are largely limited by utilizing rootstock resistant to Ca. P. pyri. With an improved perspective on the biological underpinnings of this complex pathosystem, it is possible to seek alternative solutions to manage pear decline and expand breeding programs for genetic variety and disease resistance. This study is the first genetic look at both the insect vector and the pathogen itself and will serve as an important step in developing new strategies for improved integrative pest management.

Technical Abstract: Phytoplasmas can negatively or positively alter vector host fitness. “Candidatus Phytoplasma pyri,” is the causal agent of pear decline in commercial pear (Pyrus communis L.; Rosales: Rosaceae) and peach yellow leafroll in peach [Prunus persica (L.); Rosaceae]. This plant pathogen is transmitted by several species of pear psyllids (Cacopsylla spp. Hemiptera: Psyllidae). We sought to explore the relationship between the pear decline phytoplasma and its US vector, Cacopsylla pyricola (Förster), at the molecular genetic level through transcriptomic analysis using RNA-sequencing methodology. We also focused on phytoplasma and insect effectors, which are secreted proteins that can modulate interactions within a pathosystem. In this study, we identified 30 differentially expressed genes, 14 candidate insect effector genes, and 8 Ca. Phytoplasma pyri candidate effectors. Two strains of Ca. Phytoplasma pyri were identified based on immunodominant membrane protein sequence analysis from C. pyricola collected in the Pacific Northwest agricultural region. Here, we present a first genetic look at the pear decline pathosystem and report gene candidates for further exploration of infection mechanisms and potential tools for integrated pest management.