Miniature Grapevine Speeds Research
Washington State University researchers are using a dwarf grapevine variety named Pixie to research potential solutions to industry problems.
“This is your lab rat for the grape world,” said Amit Dhingra, assistant professor of horticultural genomics and biotechnology. “With Pixie grape, you can advance and accelerate solution delivery to the stakeholders for the challenges they are dealing with in their vineyards.”
Pixie grape is a mutant of Pinot Meunier, a grape variety widely used in making Champagne. A genetic mutation in Pixie makes it insensitive to gibberellic acid, a plant hormone that regulates growth and development. This accounts for the plant’s small stature; a mature Pixie grape plant is only about 18 inches tall.
In addition to its small stature, when started from a cutting, Pixie starts to flower in about three or four months and then continues to produce flowers and fruits throughout the year. Most grape varieties flower for the first time during their second or third year and produce fruit only once a year thereafter.
“Pixie is a great candidate for research and education because of its small size,” said researcher Kathie Nicholson, a horticulture graduate student working in Dhingra’s lab. “It takes up a lot less room than a normal-sized plant.” The plant uses fewer inputs, such as water and fertilizer, meaning it is a cost-effective research tool.
Because Pixie matures so quickly, it also accelerates research. “Pixie is a very good surrogate to test the function of fruit-related genes because we are not waiting three to four years to see the effect of a gene,” Dhingra said.
There are several ongoing research projects utilizing Pixie in Dhingra’s genomics lab.
Graduate student Kathie Nicholson is investigating the effects of 2,4-D on grapes. 2,4-D is a systemic herbicide used in the control of broadleaf weeds. It is the most commonly used herbicide in the world, and the third most common in North America.
This herbicide is not used in the vineyard, but it is used on nearby crops, such as corn and wheat, to control weeds, and sometimes drifts on the wind into vineyards where it can damage plants. Nicholson is looking for grape cultivars with 2,4-D resistance. She hopes to identify the gene that gives certain cultivars that resistance and to then transfer that resistance gene to other grape varieties. “We want to see what kind of effect 2,4-D has on Pixie, and see if we can transfer or mutate that gene,” said Nicholson. “Then 2,4-D would no longer be a problem.”
Currently, two WSU undergraduates are working on research projects with Pixie. Tyler Armour, a senior in the viticulture and enology program, is working on a regeneration protocol for propagating Pixie grape. Instead of growing grapes from seeds or cuttings he is trying to grow shoots from single cells or plant “stem” cells.
Armour takes leaf tissue, wounds it by cutting it into strips, placing in on a growing media in a bath of growth hormones. “If you get the hormone ratio right, you can get the cells in the leaves to start thinking they’re shoots, and get shoots growing from single cells,” said Armour. “In order to introduce new genes or alter existing genes to help solve growing issues, you need to be able to introduce the new genes at a single-cell level, so the entire plant has the new gene.”
Armour’s research is being funded by an Auvil Fellowship and a CAHNRS Undergraduate Research Grant. Another viticulture and enology senior, Dane Scarimbolo, received a CAHNRS Undergraduate Research Grant for his research on Pixie grape.
Scarimbolo is isolating and sequencing the gibberellic acid-sensitive gene that, when mutated as in Pixie and other plants, causes dwarfing. Scarimbolo’s research opens up the possibility of mutating the gene in particular grape varieties.
“We want to dwarf, for instance, Cabernet and Chardonnay for research,” said Scarimbolo. “We want something that we can grow and have results in three months in greenhouse testing.”
by Holly Luka, Marketing and News Services intern
Gaining Ground for Applied Research
WSU viticulture researchers have received contributions from the wine and grape industry to fund a new eight-acre research vineyard. Vines were planted recently near the Irrigated Agriculture Research and Extension Center in Prosser.
Markus Keller, Chaeteau Ste. Micheel Distinguished Professor of Viticulture, pointed out that, “Currently, our research vineyards are small and scattered across the research center. They’re older vineyards, so don’t reflect current practices. The new vineyard will allow us to better serve the industry in a number of important research areas.”
Once established, the vineyard will accommodate field trials with Washington’s “big-four” varieties: Cabernet Sauvignon, Merlot, Chardonnay and Riesling. Planned research projects will commence after the vines reach at least four years of age and include advanced deficit irrigation strategies, canopy and crop load management, as well as projects testing mechanized or automated precision-viticulture practices.
The $55,000 needed for first-year vineyard establishment came from a variety of sources all across the industry, Keller said, “with the Washington State Department of Agriculture agreeing to match the industry contributions.” The Washington Wine Industry Foundation and the Wine Advisory Committee both agreed to contribute a majority of the needed funds with the Washington Association of Wine Grape Growers filling in the remaining gap.
“The new research vineyard will greatly enhance WSU’s ability to address the industry’s research needs,” said Vicky Scharlau, executive director of the Washington Wine Industry Foundation, “not to mention allowing researchers to be more efficient and produce the output we need to compete globally. Research is our future, and the industry was all too happy to assist WSU by funding this vineyard.”
Upcoming Workshops and Tours
Advanced Sensory Workshop
August 24 on the WSU Tri-Cities campus. In this all-day workshop, we will look in detail at several wine defect aromas and some grape varietal flavor aromas with presentation of examples and experience of your own personal detection threshold. Presenters include WSU and industry winemaking and sensory science experts, including Kerry Ringer, Carolyn Ross, Thomas Henick-Kling. For more information, contact Debbie Schwenson.
New Zealand Winery Tour
November 15 – 28. “We’ll be visiting 17 wineries, some of which never accept visitors, so we are in for a special tour,” says trip organizer and program coordinator for WSU’s professional certificate programs in viticulture and enology, Theresa Beaver. “Visits have been arranged with many of the best wineries in New Zealand and they are looking forward to meeting us!” This trip will be of interest to anyone who is interested in making wine or growing grapes. Click here to download a flyer with more info »