Performing Department
(N/A)
Non Technical Summary
Potatoes are a staple food crop globally, critical to food security and economies. However, the potato tuber blemish disease known as powdery scab, caused by Spongospora subterranea f. sp. subterranea (Sss), poses a significant threat. This disease causes blemishes on the tubers, making them unmarketable. Moreover, Sss is the only known vector for the virus, potato mop-top virus (PMTV), which can cause tuber necrosis and result in end-of-season losses for potato growers. Currently, there are no effective management strategies or chemical treatments to suppress either pathogen. To address these challenges, we are investigating how soil microbial communities might suppress powdery scab. We aim to identify of beneficial microbial communities that are associated with suppression of powdery scab by conducting greenhouse experiments with field soils that have been shown to either reduce or support disease.We anticipate that our research will provide the groundwork to develop new tools to help farmers assess the risk of powdery scab and PMTV in their fields. Additionally, we aim to identify agricultural practices linked to disease suppressive activity, allowing growers to adopt practices that promote soil health. In total, results of this project will contribute to the development of disease management strategies that are both effective and economically viable to prevent end-of-season losses caused by Sss and PMTV. We will be sharing our progress and findings with the agricultural community and the public through an established LinkedIn profile and peer-reviewed publications. This initiative is a crucial step towards securing the health and productivity of potato crops, benefiting both growers and consumers.
Animal Health Component
0%
Research Effort Categories
Basic
70%
Applied
30%
Developmental
(N/A)
Goals / Objectives
Our goal is to improve management of potato powdery scab, caused by Spongospora subterraneaf. sp.subterranea(Sss), and potato mop-top virus (PMTV). To do this, we developed an approach that focuses on Sss, the vector of PMTV. Specifically, we plan to gain deeper insight into the biotic and abiotic factors in soil that contribute to powdery scab incidence and severity, and identify agricultural practices that may enhance disease suppression. Our primary hypotheses are that 1) soil microbial communities contribute to disease suppressive activity in soils and 2) disease suppressive activity of soil is affected by soil salinity. To test these hypotheses, we proposed the following objectives:Objective 1. Characterize the specific soil microbial taxa linked to the suppression of powdery scab and identify indicator species associated with powdery scab suppression.Objective 2. Identify the soil physical and chemical properties that correlate with shifts in microbial communities associated with disease suppression and examine if salinity affects the soil microbial community and powdery scab incidence or severity.
Project Methods
We will conduct two greenhouse experiments to identify soils with powdery scab suppressive and characterize the microbiomes of soils with suppressive activity associated with biotic soil characteristics and determine if differences in disease expression or suppressive activity is associated with soil salinity.To do this, we will collect potato soils from multiple fields in the Columbia River Basin and Klamath Falls region of Oregon for their powdery scab suppressive activity. Field soils will be selected due to their diverse physical properties and planting histories. Soil characteristics will be measured, including soil moisture and temperature at sampling, soil texture, soil pH, organic matter, soluble salts, cation exchange capacity, and a routine nutrient analysis. Sss inoculum present in the soil will be quantified. A greenhouse bioassay will be performed to assess powdery scab suppressive activity. Briefly, potato plants planted in the field soils will be inoculated with sporosori collected from S. subterranea-infected tubers using published methods. Powdery scab incidence and severity will be evaluated for each plant by counting the number of galls on the root system and estimating the percent of the tuber surface that is covered by lesions for all tubers. The potato rhizosphere and bulk soil will be sampled, and DNA will be extracted after a four-month growing period. Bacterial and fungal community composition will be assessed using amplicon sequencing and the open-source platform QIIME will be used to optimize sequence data and to assign taxonomy. The UNITE and SILVA databases will be used to assign taxonomy for fungi and bacteria, respectively. Sampling depth will be normalized, to account for the difference in sequencing depth, and data may be transformed prior to statistical analysis.For both greenhouse experiments, analysis of variance will be used to determine how powdery scab incidence and severity and potato phenotypes vary as a function of experimental treatment. Similarly, regression analysis will be used to examine links between plant health and field-level physical and chemical soil characteristics. Univariate and multivariate analyses will be used to identify correlations between soil microbial communities, disease incidence or severity, potato productivity, and soil physical, chemical, or biological characteristics. Analysis of bulk and rhizosphere microbiomes will help identify if core microbial communities recruited by potatoes result in community structures and taxa that are more similar across treatments when compared to those of bulk soils. In total, our analyses will help elucidate links between microbial community structure and disease suppressive activity and/or soil salinity. Finally, we will use indicator species analysis to identify OTUs associated with disease suppressive activity or salinity response.Information and results from this project will be disseminated to farmers in the Pacific Northwest region through talks at grower education events and field days, through stakeholder networks, and through informal conversation at grower education events (e.g., meetings, field days, etc.)Short-, medium-, and long-term metrics and evaluation of progress metrics.Short3-4 Experiments/surveys completedAnalyses completed2-3 Presentations at scientific meetings2-3 of extension publications and/or media produced100+ clientele reached at field days and grower education eventsMedium2-3 Journal articles/publications generatedDissertation writtenDegree completionGrower understanding of key soil health building practicesLongIndustry/processor adoption of our assessment recommendationsFarmers testing their soils and assessing soil physical and biological quality in ways that are relevant to potato productionExpectations for achievement of evaluation metrics will be discussed and defined at the start of the project. Each year, we will collect data on each evaluation metric and report on annual progress. Evaluation metrics may be adjusted in subsequent years depending on our achievement and new knowledge that is gained. Evaluation metrics will be summarized at the end of the project to document overall accomplishments. We expect long-term metrics may be challenging to evaluate before the project is completed.