Location: Temperate Tree Fruit and Vegetable Research
Project Number: 2092-30400-001-019-T
Project Type: Trust Fund Cooperative Agreement
Start Date: May 1, 2026
End Date: Apr 30, 2028
Objective:
1. Develop an antibody test for X-disease effectors in plants and compare its sensitivity to current qPCR methods.
2. Assess the antibody test for result consistency between multiple samples from the same trees.
3. Create a field lateral flow kit for consultants and growers to test for ease of use and X-disease detection from plant tissue.
Approach:
This project aims to develop a rapid, field-deployable testing method for early detection of X-disease in cherry trees. The disease poses a serious threat to the cherry industry, particularly because infected trees—especially non-fruiting ones—can remain asymptomatic for years, allowing the phytoplasma to spread undetected. Early and reliable detection is therefore critical for effective disease management.
Recent research has identified several effector proteins produced in high concentrations by the X-disease phytoplasma. Some of these effectors contain signal peptides, acting like “shipping labels” that direct the proteins to various parts of the plant. This suggests that the effectors may move systemically and could be detectable even when symptoms are absent, making them promising targets for early detection through random tissue sampling.
Our approach leverages antibody-based detection methods to develop a lateral flow assay (LFA), similar to rapid diagnostic tools like pregnancy or COVID-19 tests. These assays are low-cost, user-friendly, and capable of detecting targets at very low concentrations. To further improve sensitivity and specificity, we will explore the use of nanobodies—smaller, more stable antibody fragments that can access target epitopes more effectively than conventional antibodies.
The study will focus on:
1. Effector Characterization – Identifying and validating X-disease effectors that are present in detectable quantities throughout the plant.
2. Antibody and Nanobody Development – Producing high-affinity antibodies/nanobodies specific to key effectors.
3. Assay Design and Validation – Developing and testing qPCR and lateral flow prototypes for sensitivity, reliability, and field usability.
4. Field Evaluation – Testing assay performance in infected but asymptomatic trees to assess detection reliability under real-world conditions.