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Elucidating mechanisms that cause potato glycoalkaloids to spike

Elucidating mechanisms that cause potato glycoalkaloids to spike

Primary author: Moe Hnin Si
Co-author(s): Sen Lin; Roy Navarre

Primary college/unit: Agricultural, Human and Natural Resource Sciences
Campus: WSU-IAREC, Prosser, WA

Abstract:

Developing new potatoes with increased amounts of phytonutrients and low amounts of neurotoxic glycoalkaloids (GLKs) benefits for producers and consumers of potato. Light-induced accumulation of GLKs and concurrent greening tubers is a major problem in rejecting greening tubers from markets, which some have estimated can cause up to 15% -17% of the crop to be culled. Metabolite levels are genetically determined, but several factors such as environmental cues or tuber color can affect their final content. Transcriptomic and metabolomic approaches were applied to monitor levels of GLKs, chlorophyll, and carotenoids, and 32 target genes (biosynthetic genes and/or regulators) in potatoes exposed to light. Levels of GLKs were markedly spiked in eight white and two color flesh genotypes among the 20 studied (10 white and 10 color), exceeding the accepted limit of 20mg/100g FW. Other genotypes had less spiking of GLKs. Metabolic analysis across different genotypes showed color potato with higher amounts of carotenoids had less GLK spiking and revealed a possible mechanism of metabolite sharing by trading of isoprenoid intermediates between the cytosol and the plastid. Only four genotypes among those tested showed a positive correlation between greening and GLKs levels, implying that potatoes showing greening do not necessarily have higher GLKs content. We assessed the relative importance of transcriptional control at GLK regulatory points by assessing gene-gene, gene-metabolite and metabolite-metabolite correlations. These findings provide insights into mechanisms that control levels of GLKs and suggest potato breeding programs may benefit from evaluating spiking potential of breeding lines.

Resolving the conflicting Hf and Nd isotope records of early Earth crust-mantle evolution

Resolving the conflicting Hf and Nd isotope records of early Earth crust-mantle evolution

Primary author: Ross Salerno
Faculty sponsor: Jeff Vervoort

Primary college/unit: Agricultural, Human and Natural Resource Sciences
Campus: Pullman

Abstract:

The timing and nature of the formation and growth of Earth’s continents has sparked debate for decades. Fundamentally, two end-member models have been proposed. One favors rapid and early di¬fferentiation of continental crust and a complimentary depleted mantle, while the other proposes and early basaltic proto-crust with true continental crust and depleted mantle forming many hundreds of millions of years later. Radiogenic isotope systems (e.g., Nd and Hf) are crucial in this debate, as they provide constraints on the timing of the Bulk Silicate Earth differentiation. Our attention focuses on the isotopic record – particularly from the Earth’s oldest rocks – to help understand the timing of crustal growth. Two fundamentally different stories appear between the Hf and Nd records of these oldest samples. Hf isotope data, now based primarily on zircon Hf and corresponding U-Pb ages, have chondritic Hf compositions through ~ 3.8 Ga – no evidence for crust or depleted mantle. The Nd isotope data, in contrast, appears to show a characteristic depleted mantle signature for these same rocks. The Hf and Nd compositions we report from the Pilbara Craton (3.5-3.3 Ga) agree – both are chondritic. These rocks preserve no evidence of a depleted mantle or significant crustal reservoir on Earth at that time. In the examples where both systems are closed [Pilbara], the Hf and Nd isotope records agree and there is no Hf-Nd paradox.

Moving Towards a Policy, Systems and Environmental (PSE) Change Framework for Extension Professionals

Moving Towards a Policy, Systems and Environmental (PSE) Change Framework for Extension Professionals

Primary author: Clea Rome
Co-author(s): Laura Ryser; Carrie Backman; Debra Hansen

Primary college/unit: Agricultural, Human and Natural Resource Sciences
Campus: Clallam County

Abstract:

The Policy, Systems and Environmental (PSE) change framework has emerged in the last decade as new way of approaching difficult and layered public health problems, including obesity, diabetes and cancer. Rather than focusing solely on individual choices, the PSE approach acknowledges the “interrelated, dynamic, and adaptive factors” (Lyn 2013) that influence an individual’s health. Public health practitioners are increasingly addressing not only an individual’s choices, but the broader landscape that influences personal behavior, including the policies, systems, and environments (PSE) that shape those behaviors (Leeman et al. 2015).

Beyond the public health sector, the PSE approach is a useful framework to guide the work of Extension leaders in many program areas to create long-term change. For example, the complex issues that Extension community development professionals work on require a framework that utilizes the University’s strength to conduct applied research for data-driven solutions at the local level. The authors have found that applying a PSE framework to community development work through Extension provides leverage points that create population-level benefits across many sectors. Extension faculty and staff have played a critical role in facilitating the process for desirable PSE change outcomes for community development through six key activities: (a) assessing the social and political environment; (b) engaging, educating, and collaborating with key stakeholders; (c) identifying and framing the problem; (d) utilizing available evidence; (e) conducting research to identify needed data; (f) identifying PSE solutions; and (g) building support and political will (Lyn et al. 2013).

Peering into Potato-Virus Interactions in the Era of Omics

Peering into Potato-Virus Interactions in the Era of Omics

Primary author: Manasseh Richard
Co-author(s): Madhu Kappagantu; Lindani Moyo; Hanu R. Pappu
Faculty sponsor: Prof. Hanu R. Pappu

Primary college/unit: Agricultural, Human and Natural Resource Sciences
Campus: Pullman

Abstract:

Potato is an important staple food crop worldwide. The tuber is especially prized for its high nutritional value, while also offering vital economic benefits. In the U.S., the Pacific Northwest produces nearly 60% of the nation’s potato annually, and potato industry in WA state alone is worth several billions of dollars. However, potato production is curtailed by several viruses, with the most devastating being Potato virus Y (PVY). At least nine biological variants of PVY are known to attack potato. These include relatively newer recombinant types named PVYNTN and PVYNWilga, which induce tuber necrosis in susceptible cultivars. So far, the underlying host-virus interactions have been studied by analysis of gene expression, while the metabolic level, which often correlates poorly with gene expression but directly mediates these phenotypic outcomes, is poorly studied. To assess how PVYNTN and PVYNWilga infections affect potato metabolism, we used GC-MS to obtain comprehensive metabolic profiles of two cultivars inoculated with these recombinants of PVY. A total of 447 peaks were detected, 115 of which were known metabolites that categorized into amino acids, sugars and sugar derivatives, esters and lactones, organic acids, alcohols, ketones and phenols, and sulfur-nitrogen compounds. Using a mix of univariate and multivariate methods, we showed that PVYNTN and PVYNWilga elicit significantly different metabolic alterations in potato. Multivariate receiver-operator characteristic (ROC) curves predicted Dioctyl phthalate, Sedoheptulose, Glycine, 1-Monopalmitin, Ribulose-5-phosphate, Trehalose, Glycerol 3-phosphate, Alpha-Tocopherol, 5-Methoxytryptamine, Sorbitol, Glucose-6-phosphate, Galactinol, L-Malic acid, and Threonic acid as potential metabolite biomarkers of PVYNTN and PVYNWilga infection in potato.

Marijuana Use and American Indian/Alaska Native Youth in Washington State

Marijuana Use and American Indian/Alaska Native Youth in Washington State

Primary author: Faith Price
Faculty sponsor: Elizabeth Weybright

Primary college/unit: Agricultural, Human and Natural Resource Sciences
Campus: Pullman

Abstract:

American Indian/Alaska Native (AI/AN) youth have higher rates of marijuana use than their peers nationally. However, substance use trends differ by region and there is immense diversity amongst Tribes. In addition, many AI/AN youth are from multicultural heritages, a group typically ignored by research.

This study used data from tenth grade respondents to the Washington Healthy Youth Survey from 2006-2018 to explore marijuana use prevalence rates amongst AI/AN-only and multicultural AI/AN youth in Washington state and the risk and protective factors influencing their substance use. Statistical analyses revealed both AI/AN-only and multicultural AI/AN HYS respondents had significantly higher marijuana use prevalence rates than their non-Native peers. Both groups of AI/AN youth were also initiating marijuana use at significantly younger ages than their non-Native peers. In addition, AI/AN-only and multicultural AI/AN tenth graders reported significantly higher means of risk factors and lower means of protective factors than non-Native youth. However, many of the risk and protective factors associated with marijuana use for non-Native youth were not significantly predictive of marijuana use for AI/AN-only youth, nor, to a lesser extent, multicultural AI/AN youth.

This study’s findings suggest that research needs to be inclusive of multicultural AI/AN health, a substantial segment of the AI/AN population that is at high risk and generally overlooked. In addition, both AI/AN-only and multicultural AI/AN youth have unique risk and protective factors from the general population which may better explain marijuana use patterns. Prevention programs must address these unique needs if they are to effectively serve AI/AN populations.

Defining Microbial Soil Health in the Inland Pacific Northwest

Defining Microbial Soil Health in the Inland Pacific Northwest

Primary author: Katherine Naasko
Co-author(s): Haiying Tao
Faculty sponsor: Dr. Haiying Tao

Primary college/unit: Agricultural, Human and Natural Resource Sciences
Campus: Pullman

Abstract:

Phospholipid fatty acid (PLFA) biomarker identification is commonly included in microbial soil health assessments. PLFAs comprise the bilayer cellular membranes of macro and microorganisms that live within soil. Previous literature has shown that PLFA biomarkers and beta-glucosidase enzyme activity are strongly correlated to SOM stocks and associated biochemical nutrient cycling, focused primarily on the surface 20 cm of soil. Many researchers have reported a significant decrease in PLFAs with increasing soil depth, correlated with less SOM to house microbial activity. In dryland cropping systems of the Palouse, winter wheat (WW) roots grow several feet deep, along with microbial communities naturally drawn to the root also, to take advantage of water and nutrients. The objectives of this study include (i) assess how winter wheat-associated microbial communities identified through PLFA and b-glucosidase activity correlate with soil organic matter stocks to 1 meter deep; and (ii) examine relationships across different dynamic soil factors (i.e. tillage intensity) and inherent properties (i.e., precipitation and temperature) of Palouse silt loam. Agricultural sites had lower PLFA biomass compared to the grass site, however the relationships between carbon stocks and enzyme activities are not as straightforward. All sites had lower indicators deeper in the soil, which positively correlates to relative availability of carbon sources for food and energy. When comparing soils from ag sites along the precipitation and temperature gradient, significant linear correlations were found.

This is supported in part through the ARCS Fellowship and the PNNL-WSU Distinguished Graduate Researcher Program.

Falling and Depression among Older Adults: Explanations, Conditions and Implications

Falling and Depression among Older Adults: Explanations, Conditions and Implications

Primary author: Kyle Murphy
Co-author(s): Shane McFarland; Myah Houghten; Marie Gray; Garrett Jenkins
Faculty sponsor: Brittany Cooper

Primary college/unit: Agricultural, Human and Natural Resource Sciences
Campus: Pullman

Abstract:
Introduction: The present study, presented at the Society for Prevention Research (SPR) 2019 conference as part of the SPR Cup, an academic competition for early-career prevention scientists, is an award-winning study, making WSU the winner of this competition for two consecutive years. With SPR-intentions to broaden prevention science in older adults (a critically understudied population with growing needs), all teams worked with the Medicare Health Outcomes Survey Data, a longitudinal, population-level dataset 1.5 months prior to presenting. Using Anderson’s Behavioral Health Model, the goal of the present study was to assess the relationships of needs-based, enabling and environmental mechanisms/processes by which falling predicts depression in older adults. Experiencing a fall increases risk for depression, which increases risk for suicidality and nursing home admission, and is related to mobility, physical health, physical activity, and health policy.

Sample: N>50,000 adults aged 65+, cohorts 2007-2014.

Method: We employed multiple group structural equation modeling to evaluate the following: 1. Mediation of falling predicting depression through mobility and general physical health; 2. Moderated-mediation by physical activity promotion; 3. Moderated-mediation by implementation of the affordable care act (ACA; designed to enhance Medicare).

Findings/conclusions: Reduced mobility and physical health explained the relationship between falling and increased depression. This relationship was consistent, however, the associative magnitude changed by condition; individuals who reported physical activity promotion with medical professionals, and individuals post-ACA implementation, were at significantly less risk. Implications for older adults, include continued prevention research and medical practices that promote physical activity. Furthermore, ACA evaluation is warranted.

Small RNA-mediated gene regulation on both sides of the wheat stripe rust interaction

Small RNA-mediated gene regulation on both sides of the wheat stripe rust interaction

Primary author: Nicholas Mueth

Primary college/unit: Agricultural, Human and Natural Resource Sciences
Campus: Pullman

Abstract:

Wheat stripe rust is a global disease that burdens farmers with yield loss and increased fungicide expenses. The causative agent, the fungus Puccinia striiformis f. sp. tritici, develops infection structures inside living plant cells, suppressing the defense response in order to steal nutrients for further growth and reproduction. While many fungal virulence-promoting factors are proteins, it was recently discovered that small RNA molecules also function in this manner by silencing complementary host genes. Meanwhile, wheat-derived small RNAs are induced or repressed during infection, yet their targets are mostly unknown. In this work, small RNA, degraded RNA, and gene expression data were combined to investigate post-transcriptional gene regulation on both sides of the host-parasite interaction. Our goal was to identify target transcripts by the observation of high transcript slicing frequency at the precise position of small RNA binding sites. Targets among fungal transcripts indicated native regulation of fungal development; wheat target transcripts indicated cross-kingdom gene silencing. Some wheat targets, but not all, showed reduced expression during infection with stripe rust, suggesting a complex pattern of gene induction and repression. Analysis of wheat microRNA loci revealed novel candidate genes in each of the three wheat subgenomes. Resistant and susceptible wheat varieties showed differential expression of microRNAs involved in the regulation of disease resistance and phosphate uptake. This work highlights the small RNA repertoire of an important plant pathogen, as well as the responses of its host. The newly-identified target genes will provide prospects for the development of pathogen control biotechnology.

Genomic Prediction of Quantitative Adult Plant Resistance to Stripe Rust in a Winter Wheat Breeding Program

Genomic Prediction of Quantitative Adult Plant Resistance to Stripe Rust in a Winter Wheat Breeding Program

Primary author: Lance Merrick
Co-author(s): Arron Carter; Xianming Chen; Brian Ward
Faculty sponsor: Arron Carter

Primary college/unit: Agricultural, Human and Natural Resource Sciences
Campus: Pullman

Abstract:

Stripe rust (Puccinia striiformis f. sp. tritici) is one of the most damaging diseases of wheat and has resulted in massive reduction in yield and economic losses globally. Quantitative adult plant resistance (APR) is detected in mature plants, associated with non-specific resistance, and considered to be a durable form of resistance. Quantitative APR is controlled by varying numbers of additive resistance alleles and thus is a good candidate for genomic prediction. The goal of this research was to create a genomic prediction model of quantitative stripe rust resistance for advancing early-generation lines to advanced yield trials in a winter wheat breeding program. We created prediction models using breeding lines from four years (2016-2019) and two breeding populations consisting of doubled-haploid and F5 derived lines. The prediction models used genotype-by-sequencing single-nucleotide polymorphism markers for random effects and KASP markers for known resistance genes for fixed effect covariates. Prediction models used were optimized for training population size, marker density, and statistical model to find the most efficient and accurate method to integrate genomic prediction into a breeding program. Genomic prediction will aid the breeding program for the evaluation and selection of stripe rust resistance in years and environments with limited disease incidence and reduce the need for replicated phenotyping. In doing this, genomic prediction will increase the genetic gain for quantitative stripe rust resistance within wheat breeding populations.

The Nefarious Sin in Colonial America and Spain

The Nefarious Sin in Colonial America and Spain

Primary author: Francisco Manzo-Robledo

Primary college/unit: Agricultural, Human and Natural Resource Sciences
Campus: Pullman

Abstract:

In this manuscript (500+ pages), a set of colonial documents, obtained from the archives in Spain, dealing with historical events and court proceedings, are analyzed from a literary point of view. A simple model is proposed to bridge the distance from the time the documents were produced, to the present. This is accomplished by considering the existence of a social act—space, a virtual space that contains all acts accepted / not-accepted by society, and the existence of different relative—realities. This project deals with morality and legal proceedings; paleography, transcription and interpretation. The book will be in Spanish.