Location: Temperate Tree Fruit and Vegetable Research
Project Number: 2092-21220-003-000-D
Project Type: In-House Appropriated
Start Date: Mar 7, 2023
End Date: Mar 6, 2028
Objective:
A priority need for agricultural research in the coming years is to help ensure food security despite challenges such as an increasing population, climate uncertainty, rising input costs, and loss of arable land. Another need for potato is research that helps the industry adapt to evolving consumer preferences because consumers are increasingly prioritizing sustainability and nutritional value when making their food purchasing decisions. Our research will address these needs using both pre-breeding and breeding approaches to identify or develop potato germplasm with better disease and pest resistance, nutritional value, sustainability, and product quality. Our project has three interrelated objectives, all of which are ultimately intended to facilitate the development of superior new potato cultivars.
OBJECTIVE 1: Utilize high-throughput phenotyping, molecular breeding strategies, and genomic prediction to characterize, breed, and release potato germplasm with improved traits, especially those related to disease and pest resistance, sustainability, and increased amounts of phytonutrients.
Sub-objective 1A: Develop and deploy high-throughput phenotyping workflows to quantify foliar and tuber characteristics of individual clones within potato breeding populations.
Sub-objective 1B: Generate and characterize multi-parent breeding populations that segregate for dominantly inherited, large-effect, pathogen resistance alleles.
Sub-objective 1C: Screen cultivars, landraces, and wild species for resistance to soil-borne pathogens and develop self-compatible, diploid introgression populations.
Sub-objective 1D: Develop new baby potato lines and characterize the genetics of traits important for a baby potato cultivar, especially the tuber high-set trait.
OBJECTIVE 2: Characterize genetic, molecular, physiological, and biochemical factors that control potato key traits, including disease and other stress resistance, yield, and processing and nutritional qualities.
Sub-objective 2A: Delineate mechanisms that mediate small molecules involved in tuber nutritional value and appearance.
Sub-objective 2B: Examine the effect of heat-stress on tuber internal defects, phenylpropanoids, and glycoalkaloid metabolism.
OBJECTIVE 3: Develop improved molecular diagnostic tools for pathogen detection to facilitate epidemiological studies of important pathogens of potato.
Sub-objective 3.A: Develop new tools for rapid identification of Lso and BLTVA phytoplasma in planta and explore the role of new genetic variants of Lso in potato in the Northwest.
Sub-objective 3B: Generate and maintain a PMTV-infected Spongospora subterranea population in the greenhouse for use in germplasm screens.
Approach:
OBJECTIVE 1: We will use modern breeding methods, and develop and deploy high-throughput phenotyping methods. Drones will collect weekly multispectral images of field trials. Tubers will be phenotyped using digital imaging and a self-built conveyor belt system with sensors to automate phenotyping of tuber number, size, shape, color, eyes, and physiological defects. Parental lines containing disease resistance alleles will be used to develop mapping populations. Populations will be genotyped using DArTseq. Diploids and germplasm from wild potato showing disease resistance will be used to produce self-compatible diploid clones. A factorial breeding population will be used to assess trait correlation and mapping. Joint linkage or association mapping will be used to map QTL and calculate GEBVs for key traits. A major breeding effort will be russet potatoes, but baby and specialty potatoes will be bred with traits including appearance, taste, high tuber number and nutritional value.
OBJECTIVE 2: The factors that influence tuber nutritional value and quality, including phenylpropanoids and glycoalkaloids will be analyzed. Time-course studies will use tubers exposed to continuous light. Flavonols will be extracted and measured with LCMS. Gene expression and transcriptomic studies will be conducted if samples show large flavonol increases. Tuber flavonol synthesis will be reprogramed by silencing anthocyanin biosynthesis to test whether this increases flavonols. Terpenoid metabolism will be analyzed in tubers exposed to light. Chlorophyll and carotenoids will be measured by spectroscopy. Glycoalkaloids will be quantitated by LCMS. Relevant genes will be measured by qRT-PCR and network analysis of gene-metabolite interactions visualized. We will develop a lab assay for defects like blackheart and heat necrosis by exposing tubers to varying temperatures. The effect of high temperatures on glycoalkaloids will be assessed in potatoes grown in WA and TX in a randomized complete block design.
OBJECTIVE 3: Molecular tools for BLTVA detection will be optimized and validated. Non-potato psyllids found on sticky traps in the Columbia Basin will be analyzed for Lso and transmission to potato tested. At two, four, and six weeks post-inoculation, symptoms will be recorded, and plant tissue will be collected and tested for the presence of Lso to assess whether successful inoculation occurred. To develop and maintain a potato mop top virus (PMTV) infected Spongospora subterranea f. sp. Subeterranea (Sss) population, various potential host plants will be inoculated in the greenhouse with Sss-infested soil. To ensure persistence of the PMTV infected Sss, we will try different methods to ensure inoculum is maintained. One method will cycle potato plants and tomato/N. benthamiana to ensure that the soil always has a potato plant present to maintain PMTV-infected Sss when the tomato needs to be replaced. A second method does not rely on the continual cycling of potato but will grind up the tomato. A third method utilizes PMTV-infected potato obtained each year by planting tubers alongside the tomato or plants to enable transmission to the host plant.
