For 2018-2019, the OWB allocated $437,500 for the support of these research grants. Below are the nine funded projects. Summaries will be provided in the fall and updates on the projects will be reported throughout the year.

Bhaskar Bondada, Associate Professor, Wine Science Center, Washington State University
Microscopy of Red Blotch: A whole new perspective for developing a mechanistic understanding of the disease and its prevention by examining cellular details of the infection

This project deals with key queries of Red Blotch virus infection in grapevines employing microscopy techniques, a powerful tool routinely used to study diseases. For instance, how does the virus enter grapevines, and once it enters the vine, how is it distributed throughout the vine? Does it change the plumbing system of the vine? What is the symptomatology of such infection at the cellular level? Addressing these questions will provide us with a better understanding of how the virus spreads in the vine and in the vineyard, so that we can eventually implement innovative approaches for disease management in Oregon and around the world.

Christopher Curtin, Assistant Professor, Department of Food Science and Technology, Oregon State University
Elucidating Brettanomyces paths of entry into the cellar

Brettanomyces yeasts are a persistent wine spoilage issue due to their ubiquitous presence in wine regions of the world. How did they get there? Where do they live when not floating around in a tank or barrel of finished wine? These questions have remained unanswered due to the challenges in finding yeasts present in the environment at very low numbers. This project is using a genomics-driven approach to optimize protocols for enrichment and isolation of Brettanomyces when present in a mixed population of yeasts. These protocols will be used to isolate Brettanomyces from the environment, evaluate spoilage potential of these isolates, and identify potential paths of entry into the cellar for spoilage strains.

Laurent Deluc, Associate Professor, Department of Horticulture, Oregon State University.
Determining the role of Auxin-Response Factor 4 in the timing of ripening initiation in Vitis vinifera

The genetic basis of the ripening control is one major long-term objective of grapevine research. In our lab, we are currently studying the activity of one protein (ARF4) that responds to auxin, a plant hormone. This protein may affect the timing of ripening initiation in grape berry. Using genetic engineering, we are currently studying the impact of this protein on fruit composition. The characterization of gene(s) relevant to a trait like ripening initiation is of great importance to develop innovative practices and identify clones/cultivars more amenable to sustaining rapidly evolving climatic conditions.

Alexander D. Levin, Viticulturist and Assistant Professor, Department of Horticulture and Southern Oregon Research and Extension Center, Oregon State University
Determination of pre- and postveraison water status targets for deficit irrigation of Pinot noir in a warm climate

Compared to other economically important cultivars, such as Cabernet Sauvignon, there are surprisingly few publications that have addressed Pinot noir responses to water deficits. Therefore, this study has been designed to fill the gap in the literature by establishing a robust field experiment in a mature, commercial Pinot noir vineyard to evaluate yield, fruit quality, and wine quality responses to the timing and severity of water deficits. Providing growers with more information regarding the effects of seasonal water deficits on vine performance is necessary for the optimization of irrigation management strategies that will ultimately reduce water use and improve Pinot noir fruit and wine quality.

Alexander D. Levin, Viticulturist and Assistant Professor, Department of Horticulture and Southern Oregon Research and Extension Center, Oregon State University
Achala KC, Plant pathologist and Assistant Professor, Department of Botany and Plant Pathology and Southern Oregon Research and Extension Center, Oregon State University
Keeping them fed and happy: Mitigating negative effects of Grapevine Red Blotch Disease through cultural practices

While entomological and viral research continues, wine grape growers desperately need more viticultural information on how to successfully farm GRBV-infected blocks in the interim period. The overall objective for this two-year project is to address vineyard management concerns by evaluating vine response to cultural practices in GRBD-afflicted vineyards. Specifically, project objectives are to (1) conduct on-farm field trials in collaboration with growers to determine best viticultural practices for the mitigation of GRBD in relation to wine grape production and fruit quality; and (2) determine the effects of mitigation practices on quality and sensory characteristics of wines made from GRBV-infected fruit.

Walt Mahaffee, Research Plant Pathologist USDA-ARS-HCRL
Persistence of fungicide resistance in Grape Powdery Mildew

This research will determine if strobilurin-resistant grape powdery mildew (i.e. reduction in growth rate, germination, sporulation) is fit for survival in vineyards in relation to temperature and UV exposure. These results will allow one to determine how long after ceasing strobilurin use the genetic mutation conferring resistance will persist in vineyards and when it will be suitable to begin using strobilurins again. It will also allow for the development of resistant mitigation strategies for other fungicides in the future.

James P. Osborne. Extension Enologist, Department of Food Science and Technology, Oregon State University
Utilizing malolactic fermentation as a tool to prevent Brettanomyces bruxellensis wine spoilage

B. bruxellensis causes wine spoilage through the production of horsey or barnyard-like smelling volatile compounds. This spoilage occurs typically during the aging of wine but can also occur at other stages of winemaking. During and shortly after malolactic fermentation (MLF), wine is particularly susceptible to Brettanomyces spoilage since sulfur dioxide (SO2), the main tool used to prevent Brettanomyces growth, cannot be added until MLF is complete. Because of this, it is recommended to conduct a rapid MLF with inoculated cultures so that the time that the wine is without SO2 protection is minimized.

An additional reason why performing a rapid MLF may aid in preventing Brettanomyces spoilage is being studied in our lab. During experiments with Brettanomyces it was noted that the yeast often struggled to grow in wine that had recently undergone MLF. The current study will build off these results and determine why the presence of O. oeni at the end of MLF inhibits Brettanomyces growth. Experiments will be conducted to investigate whether certain strains of O. oeni are more effective at inhibiting Brettanomyces than others and also whether Brettanomyces strains are equally sensitive. While wineries must continue to use sound winemaking practices to prevent the growth of Brettanomyces, results from this study may provide winemakers with an additional strategy/tool to help prevent wine spoilage by Brettanomyces. If certain O. oeni strains show inhibitory action towards Brettanomyces then use of these strains could be an additional ‘hurdle’ that Brettanomyces must overcome. MLF with a particular strain or managed in a certain way could provide protection for wine in the window between when MLF is completed and when an addition of SO2 can be made, a time at which wine is most vulnerable to B. bruxellensis infection.

Paul Schreiner, Research Plant Physiologist, USDA-ARS-HCRU
Comparing nitrogen fertilization in the vineyard versus supplementation in the winery on quality of Pinot noir and Chardonnay wines and productivity in the vineyard

Nitrogen (N) is a critical nutrient to manage in wine grape production because it influences vine growth and fruit quality. This research is testing how N fertilization in the vineyard (soil and foliar) alters vine productivity and wine properties in Pinot noir and Chardonnay, and whether N additions in the winery can be used in lieu of vineyard N to boost fruit N and favorably alter wine composition. The Oregon wine industry will benefit by understanding how to best manage N inputs to create optimal wines, maintain productivity, and reduce the environmental impact of wine production.

Jeremy B. Weisz, Assistant Professor of Biology, Linfield College
Terroir and Microbiomes: Examining the impacts of environmental variations and farming practices on wine grape microbiomes

Wine grapes, like most things, have a microbiome: a community of bacteria, yeast, and other microbes living on them. This microbiome is important in the vinification process. Any microbe that is on the grape may end up in the fermentation, which may influence the progression of this process. This research seeks to investigate how differences in geography and farming practices influence the microbiome of grapes, leading to a specific microbial terroir. Vineyard managers and winemakers can use the results from this project to help make decisions about how terroir and its management influence the microbiome and the resulting wine.