Grape Breeding and Human Nutrition in a Flash
The NGWI Annual meeting featured research "flash presentations" by prominent researchers from the University of California, Davis. Designed to be quick and concise, the presentations covered breeding for resistance to Pierce's Disease, as well as powdery mildew resistance. A final presentation outlined work in human nutrition from the Foods for Health Institute which may hold promise for learning more about the benefits of grape consumption.
Grape Breeding
The first presentation was made by Dr. Andy Walker, a professor in the Department of Viticulture and Enology. Dr.
Walker's rootstock and scion breeding program studies the genetics of resistance to a wide range of vineyard pests, looking at their genetic diversity and aggressiveness, as well as the host/pest interactions with grape species. His lab is actively involved in breeding wine, table, raisin grapes for resistance to Pierce's disease and powdery mildew. Lab activities include classical breeding and inheritance studies, the development of rapid resistance assays, field trials of promising rootstock and scion selections, DNA marker analysis and mapping, and characterization of candidate resistance genes.
Walker briefly explained the preliminary work in his lab, which identified a single dominant gene resistant to Pierce's disease in Vitis arizonica, for which they genetically mapped and developed markers. They then used DNA markers linked to resistance to rapidly identify resistant and susceptible progeny in crosses between V. vinifera and V. arizonica. His lab then used aggressive growing techniques to get fruit and seeds in the plant's second year, while using DNA markers each generation to eliminate susceptible and identify resistant plants. Within 12 years of crossing back to V. vinifera cultivars, Walker attained selections that are about 97% V. Vinifera. In so doing, he moved from first generation grapes with peppery, herbaceous flavors and blue-purple pigments to grapes with high quality Vinifera character, while possessing strong resistance to Pierce's Disease.
The second presentation was made by Dario Cantu, an assistant professor in the Department of Viticulture and Enology, who is a systems biologist with a background in genomics and bioinformatics. Cantu's research group uses genomics, genetics, and bioinformatics to understand plant disease resistance. He also studies how pathogenic microorganisms infect plants, cause disease, and evolve to overcome plant host resistance and chemical control strategies. His integrated, systems-oriented approach provides a novel framework for the development of strategies to achieve durable genetic resistance to important diseases in grape such as powdery and downy mildew.
Cantu uses cutting-edge DNA and RNA sequencing technologies in combination with bioinformatics to sequence, assemble, and analyze the function and structure of plant and microbial genomes. A large number of genes conferring strong resistance have been identified in V. vinifera grapes and other wild species of grape. Cantu explained that he is now working to select the best combination of resistance genes to stack together using traditional marker assisted breeding methods. The combination of multiple and diverse resistance functions will result in varieties with more effective and durable disease resistance.
In addition to looking at genetic resistance in plants, Cantu studies how pathogens cause disease and how pathogen populations evolve in response to strong selective pressure. According to Cantu, understanding how powdery mildew populations evolve is critical to determine the best combination of resistance genes to be stacked together to reduce the likelihood of development of new virulent strains.
Human Nutrition and Grapes
The final presentation explored how dairy waste products - and potentially grapes and grape products --- may play a critical role in American diets of the future, where management of favorable bacteria in the digestive system will be a key goal.
Dr. Bruce German is a Food Chemist and is the Director of the
Foods for Health Institute, UC Davis.
Dr. German's laboratory group focuses on research seeking to understand how to improve foods and their ability to deliver improved health. He explained how milk evolved to make healthy mammals healthier. According to German, milk is the only biomaterial that has evolved under the Darwinian selective pressure for the specific and sole purpose of nourishing growing mammals. Interestingly, the third most abundant biomolocules in human breast milk are indigestible by babies. These are milk "oligosaccharides", a type of carbohydrate whose purpose is to feed the development of beneficial bacteria in the gut of babies. Putting science into practices, a combination of human milk oligosaccharides plus beneficial bacteria can help vulnerable people, from babies to cancer patients.
With grants from the California dairy industry, Dr. German and his team have evaluated dairy milk constituents, learning that a waste product - liquid whey - contains these valuable oligosaccharides. It appears that these same constituent elements may be present in other food products or processes - including grape pomace.
According to Dr. German, ultimately human nutrition may move to the realm of personal microbiome management. This may be aided by the successful recovery of bioactive compounds, delivering health-promoting functional foods and potentially aiding in waste management by finding alternative uses of today's waste products. Dr. German predicted that selective use of polysaccharides will be a new component of the human diet in "Agriculture 2.0", comprising as much as 5 - 10% of caloric intake. Dr. German concluded by pointing out that our microbiota impact human immune function, metabolism, infection, cognition and mood. "Feeding our microbiota will become a key component of our 21st century diets," according to German.
The complete presentations may be viewed on the NGWI website, click here.
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