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ARS Home » Pacific West Area » Wapato, Washington » Temperate Tree Fruit and Vegetable Research » Research » Research Project #441249

Research Project: Genetic Insights into Leafhopper/Phytoplasma Interactions and Gene-Based Immunization for Plant Disease Control

Location: Temperate Tree Fruit and Vegetable Research

Project Number: 2092-22430-003-041-R
Project Type: Reimbursable Cooperative Agreement

Start Date: Oct 1, 2021
End Date: Sep 29, 2024

This project’s overall focus is on biological mechanisms underlying X-disease in cherry and other stone fruit, which is caused by phytoplasma bacteria that are transmitted by leafhopper insects. Our project will investigate genetic interactions between phytoplasma and its leafhopper vectors. The ultimate objective will be to adapt this knowledge to novel genetically-based control methods being developed for citrus greening and potato zebra chip diseases to immunize cherry trees against the X-disease phytoplasma. 1. Whole genome sequencing of the Colladonus reductus and C. geminatus leafhoppers to provide comprehensive genetic resources on these X-disease vectors and facilitate transcriptomic studies in Objective 2. 2. Expressed RNA sequencing of various plant-disease causing phytoplasma as well as their insect vectors during the insect vectoring stage of the phytoplasma life cycle. Analyses of the transcriptomes will provide fundamental knowledge on the biology of and molecular interactions between phytoplasma bacteria and their insect vectors. 3. Identify candidate target genes to adapt PHACT technology to immunize cherry and stone fruit trees against the X-disease phytoplasma.

The genomes of the primary leafhopper vectors of X-disease phytoplasma will be sequenced. Transcriptomic catalogues will be developed of all genes expressed by leafhoppers and phytoplasma during infection of leafhopper and these catalogues will be analyzed to identify the genes that putatively mediate X-disease phytoplasma interactions with their hosts. A comparative approach will be taken, examining leafhoppers that are either infected or not infected with the bacteria. Further insights will be gleaned by also examining gene expression in other hemipteran insects that are either infected or not infected with bacteria that they transmit to their respective hosts. Candidate genes that mediate the life cycle of the bacteria will be identified and selected for trials in a novel genetically-based plant-immunization approach to protect the cherry trees from phytoplasma infection.