Date: January 2024
Authors: Paige Beuhler and Ines Hanrahan
For 2024, the Washington Tree Fruit Research Commission (WTFRC) approved $230,561 to help fund six (6) new projects. The Oregon Sweet Cherry Commission (OSCC) is co-funding three (3) projects, and the Northwest Nursery Improvement Institute (NNII) contributed $25,000 to one (1) new project.
2024 New Cherry Project Details:
Project Title: Precision Agriculture: Innovating Cherry Disease Management with DPI
Organization (s): USDA-ARS
Principal Investigators (s): Pitino, M., Cooper, R., Marshall, A.
Total Funding Amount for All Years: $105,000
Length: Three Years
The Direct Plant Infusion (DPI) method is a groundbreaking approach for assessing the efficacy, mobility, and phytotoxicity of therapeutic compounds. It operates within the controlled environment of a greenhouse and expedites therapeutic molecule evaluation using small plants. To solve a major disease in a fruit tree, two components are needed: therapeutic molecules and a method of tree delivery. This project uses direct delivery into the phloem as the delivery method.
Objectives:
- Investigate the mobility of therapeutic molecules and marker signals delivered through direct plant infusion: We will examine how therapeutic molecules, as well as marker signals, move within plant tissues when delivered through the direct plant infusion (DPI) method. Understanding their mobility is crucial for optimizing treatment distribution and efficacy.
- Investigate the effectiveness of therapeutic molecules delivered through direct plant infusion in decreasing phytoplasma titer and improving plant fitness: We will assess the efficacy of therapeutic compounds administered via DPI in reducing the population of phytoplasma within plant tissues. Additionally, we will examine treatment effects on overall tree health and fitness, including factors like growth and symptom development.
- Investigate the effectiveness of therapeutic molecules delivered through direct plant infusion in decreasing Colladonus montanus. reductus and C. geminatus fitness: We will evaluate the effectiveness of therapeutic compounds delivered through DPI in reducing the fitness of C. montanus reductus and C. geminatus insect vectors. We will determine the extent to which DPI-based treatments can hinder the development and reproductive capabilities of these insects.
- Initiate field evaluation with commercially available injection systems: By utilizing commercially available injection systems, we ensure that our findings are not only scientifically valid but also practically applicable and accessible to industry stakeholders. Field evaluation will provide valuable insights into the feasibility and scalability of trunk injection technology in cherry.
Project Title: Sustainable Cherry Protection with Symbiont
Organization (s): USDA-ARS
Principal Investigators (s): Pitino, M., Cooper, R., Marshall, A.
Total Funding Amount for All Years: $144,000
Length: Three Years
Symbiont technology is a novel strategy and offers the ability to deliver biotherapy to existing plants in the field and produce desired defense molecules. Subsequently, the bacteria die off, and the symbiont continues to deliver molecules into plant stems. Most concerns with whole-plant GMOs are gene flow or consumption of transgenic food. These would not be an issue because Symbiont cells cannot form whole plants, pollen or seed (due to the phytohormone production). Symbiont cells remain localized at point of attachment and cannot survive in the environment if removed from the plant. Over the past year, ongoing work has focused on expressing proteins within Symbionts that can be exported to the host plant. The team has identified over 40 different antimicrobial peptides to test. The application of the innovative Symbiont technology holds immense promise for the cherry industry. As the team embarks on adapting this technology from its successful implementation in citrus to the challenges posed by X-disease phytoplasma in cherry trees, they anticipate a range of significant benefits that will directly impact the cherry industry, such as improved orchard sustainability, minimized environmental impacts, and future adaptability.
Project Title: Evaluation of Simple, Cheap Tests for X-Disease in Bare Root Trees
Organization (s): Washington State University, Oregon State University
Principal Investigators (s): Harper, S., Galimba, K., Kalcsits, L.
Total Funding Amount for All Years: $10,000
Length: One Year
A key hurdle for X-disease management is the high costs associated with molecular testing of X-disease in cherry and stone fruit trees. Accumulation of phytoplasma in roots during winter may allow for simple bioassays of non-fibrous roots and dormant tissues. Of course, this is logistically infeasible for existing orchards, but may provide a pathway for large scale sampling of nursery stock within cold rooms over the winter. Two of the significant pathways affected are sugar and starch synthesis in the leaves, and the transport of these sugars throughout the plant during the active growing season. This physiological effect raises the possibility of being able to stain sampled tissues with histochemical stains and differentiate between infected and uninfected trees. While this is currently being evaluated in leaves, taking advantage of this phenomenon is most logistically feasible in dormant trees and/or root tissues, where the effects of altered starch accumulation should be most apparent. In addition, some stains may be able to reveal (with a microscope) the presence of phytoplasma aggregates in phloem tissues. This study’s goal is to support the WTFRC research priorities of 1) optimizing or new testing methods for early disease detection, and 2) using research-informed solutions to reduce costs, turn-around time, and for non-symptomatic trees, by examining whether cheap histochemical stains can be used to determine X-disease phytoplasma presence in sections taken from, for example, dormant young trees prior to planting. The team plans to identify a simple staining system that can be used to discriminate between woody tissues from phytoplasma-infected and uninfected plants and compare the accuracy of stain methods to qPCR. If successful, the team will develop a training guide to teach the staining protocol to end users.
Project Title: Evaluation of UV-C for Management of Cherry Diseases and Pests
Organization (s): USDA-ARS
Principal Investigators (s): Collum, T., Leskey, T.
Total Funding Amount for All Years: $38,294
Length: Three Years
Several fungal diseases including brown rot (Monilinia spp.), blue mold (Penicillium expansum), gray mold (Botrytis cinerea), and Alternaria rot (Alternaria spp.) can lead to severe losses in sweet cherry. Currently, the use of fungicides is a major component of disease management for these pathogens. However, due to concerns about fungicide resistance, increasing regulatory restrictions, and consumer demands there is a need for additional control strategies. Scientists at the Appalachian Fruit Research Station have demonstrated that UV-C and Far UV treatments of less than 30 seconds can kill several fungal pathogens including Penicillium expansum, Botrytis cinerea, and Collectrotichum spp. in direct laboratory assays and were effective in controlling anthracnose fruit rot on strawberries. UV-C treatments also reduced arthropod pests including two-spotted spider mites and the invasive spotted wing drosophila (SWD), Drosophila suzukii, infestation on strawberry plants and fruit, respectively, and greenhouse whitefly on tomato. However, the effectiveness of UV-C or Far UV on other fungal pathogens, pests or on sweet cherry fruit is unclear. In this project, the team will explore the efficacy and minimum dose of UV-C (254nm) and Far UV (222nm) required to control sweet cherry fungal diseases and SWD in direct laboratory assays, on fruit surfaces and internally for SWD, and in combination with biocontrol products such as Bio-Save. Results generated from these studies will provide baseline information on the efficacy of UV-C and Far UV treatments against sweet cherry postharvest fungal diseases and SWD.
Project Title: Investigating Bacterial Canker Disease of Cherry in Young Orchards
Organization (s): Washington State University
Principal Investigators (s): Zhao, F.
Total Funding Amount for All Years: $157,787
Length: Three Years
Bacterial canker disease (BCD) of sweet cherries is a serious disease and worldwide problem for cherry production, causing significant tree and crop losses, especially in nurseries and young orchards. As an example, the PNW has experienced its worst outbreak of the disease during the 2022 and 2023 seasons, which led to tree death up to 40% to 70% in severe cases in Washington and Oregon, especially during the first 2 years after planting. The disease is caused by pseudomonads, a notorious pathogen associated with both plants, weeds, and the water cycle, even snow. Pseudomonas syringae is a species complex, which is composed of over 60 host-specific pathovars, belonging to at least 13 phylogroups. Pseudomonas causes infection mainly in young trees through tissues that are damaged by frost, pruning/heading cut, leaf scars, bud, and insect wounds. In Washington and Oregon, the main symptom of BCD includes canker with ooze (gummosis) and dead bud, leading to tree death; shot hole/leaf spot can also be observed. Investigating BCD of sweet cherries and providing answers for some urgent questions are critically needed. Zhao’s objectives are to:
- Determine the etiology of bacterial canker disease and their copper and kasugamycin resistance status.
- Survey nurseries and young orchards and investigate factors contributing to the outbreak of bacterial canker disease.
- Develop and recommend best management practice for bacterial canker disease in nurseries and young orchards.
Project Title: Understanding Food Safety Risks During Post Harvest Cherry Production
Organization (s): Washington State University, Washington Tree Fruit Research Commission
Principal Investigators (s): Murphy, C., Mendoza, M.
Total Funding Amount for All Years: $220,271
Length: Three Years
Since cross-contamination during postharvest processing and handling has been identified as the likely cause of many produce-related L. monocytogenes recalls and outbreaks, understanding circumstances that lead to increased contamination risk is needed to develop best management practices and other tools that stakeholders can implement to safeguard food safety. In the Pacific Northwest, cherries are hydrocooled as soon as possible after harvest and transported in cold flume water during packing to lower the fruit temperature, reduce the respiration rate, and remove organic materials from the cherry surfaces. Currently, no published research exists on the microbial quality of water used throughout the postharvest handling of cherries. Additionally, when warm produce is submerged in cool water via hydrocooling or in a flume system, the temperature differential creates a vacuum resulting in water being taken up into the produce. If the water used for hydrocooling or in the flume system is contaminated with bacteria then those microorganisms can be drawn into the produce along with the water, thus contaminating the inside of the produce (i.e., internalization). Currently, no published research has examined the risk associated with post-harvest water usage and pathogen internalization for cherries. This is especially of interest since cherries are highly susceptible to splitting during hydrocooling and while in flume water, due to the rapid water uptake resulting in a turgor pressure increase to a point beyond the expansion capability of the cherry. Since gaps in research leave the cherry industry vulnerable to opportunities for contamination and a lack of science-backed recommendations, this project outlines a series of research projects aimed at generating data for the cherry industry that can be used to direct future practices and inform decisions aimed at reducing postharvest risks. This project aims to evaluate the prevalence of Listeria spp. in commercial cherry packinghouses, the potential for L. monocytogenes under a variety of relevant industry conditions, and evaluate the microbiological status of postharvest cherries and water to understand the change in microbial status from receiving to packing.
Contact:
Paige Beuhler (Administrative Officer): paigeb@treefruitresearch.com, 509 665 8271 ext. 2
Ines Hanrahan (Executive Director): hanrahan@treefruitresearch.com; 509 669 0267
