College of Agricultural, Human, and Natural Resource Sciences

Regenerating Pixie is Important Step in Grasping Grape Genetics

Understanding the grape genome in all its vast variety will translate into sustainable viticulture practices and a deeper understanding of wine quality. Wine grape growers have been plagued by an economically devastating pest, phylloxera, which has necessitated the replacement of almost all vines with new ones grown on pest-resistant rootstocks. Fungal diseases are not only an economic threat but an environmental one as well, since heavy fungicide treatments are required to beat back the spread of powdery mildew.

Graduate student Kathie Nicholson holds regenerated Pixie grape plants. Photo by Brian Charles Clark/WSU.
Graduate student Kathie Nicholson holds regenerated Pixie grape plants. Photo by Brian Charles Clark/WSU.

Getting a grip on grape genetics requires not just the sequencing of entire genomes but detailed pictures of which genes do what. To get that information, scientists need a way to quickly grow sample plants that have been genetically transformed. Transformation means that a particular gene is silenced or added to the organism in order to learn what effect the change has on the plant.

“We need regeneration in order to do transformation,” said Kathie Nicholson, a doctoral student working in horticultural genomicist Amit Dhingra’s lab. “But it’s been hard to find a reliable method of regenerating grape in the lab.” Regeneration is a carefully controlled laboratory technique in which whole plants are grown from a few cells.

Nathan Tarlyn, one of Nicholson's co-authors, working on a plant tissue culturing project. Photo by Brian Charles Clark/WSU.
Nathan Tarlyn, one of Nicholson’s co-authors, working on a plant tissue culturing project. Photo by Brian Charles Clark/WSU.

Nicholson is the lead author of a paper that outlines a grape regeneration technique she and her colleagues developed using Pixie, a dwarf variety that flowers continuously and reaches maturity in just a few months. Only available since 2006, Pixie appears to be an ideal candidate as a grape “lab rat”: it grows quickly, does well in the greenhouse, takes up very little space and, now, can be regenerated reliably. In other words, Nicholson and her team’s work is an important step forward in the development of a tool that can be used to understand grape genetics.

“Technically, traditional breeding is genetic transformation,” Nicholson said, but traditional breeding is like taking a slow boat to an uncertain shore: you don’t know when you’re going to get there and you can never be sure where you are going. With the systematic exploration of gene function, Nicholson said, researchers will be able to zero in on the precise factors that give a plant resistance to certain diseases, the ability to withstand stresses like cold and drought, and the ability to produce the combination of complex chemicals that are so prized by winemakers.

Granted, Nicholson said, Pixie may not be an ideal model for studying wine grape genetics (although Pixie was developed from Pinot Meunier, an important grape used in the production of champagne.) “That’s why we are trying the same regeneration protocol on Chardonnay and Merlot,” she said.

Plants have the ability to regenerate themselves from a single cell. This ability, called totipotency, is sometimes compared to the ability of animal stem cells (which are pluripotent) to differentiate themselves into the wide variety of cells in an organism. A plant cell can divide, differentiate, and become the cells of shoots, roots, and leaves. This, anyway, is the theory: getting a few plant cells to differentiate and grow into mature plants in the lab is much more difficult.

Nicholson and her colleagues experimented with a variety of mixes of plant growth hormones and regimes of light and dark in order to find the sweet spot that encouraged the regeneration of Pixie. Starting with a tiny piece of leaf from the very top of a plant, she and her team found that a particular combination of stress-easing dark, a particular ratio of hormones, and a nutrient medium coaxed the cells to regrow into new Pixie plants.

Nicholson did the regeneration work as part of her Master’s degree program. Now, as a doctoral student, she is continuing her investigation of regeneration techniques, while also working to explore the genetic differences between wine grape varieties.

Brian Clark

This article is based in part on a paper by Nicholson et al. in Plant Cell, Tissue and Organ Culture and available online at

Read more about Pixie in Voice of the Vine, WSU’s wine science e-newsletter for wine lovers: June 24, 2010 and Oct. 30. 2008.

Leave a Reply

Neither your email address nor comment will be published. Required fields are marked *

CAHNRS is more than agriculture. With 24 majors, 19 minors, and 27 graduate level programs, we are one of the largest, most diverse colleges at WSU. CAHNRS Cougs are making a difference in the wellbeing of individuals, families, and communities, improving ecological and economic systems, and advancing agricultural sciences.



CAHNRS students are awarded more than $600,000 in scholarships annually.


CAHNRS has 39 student clubs and organizations to enhance student experiences and opportunities.


With 24 majors, 19 minors, and 27 graduate level programs, CAHNRS is one of the largest, most diverse colleges at WSU.


CAHNRS leads in discovery through its high-quality research programs. In 2014, CAHNRS received research funding exceeding $81.5M. This accounts for nearly 40% of all research funding received by WSU.  


Fall undergradsUndergraduate Studies

Check out every department and program CAHNRS has to offer, from Interior Design to Agriculture to Wildlife Ecology. We have 13 departments and schools to prepare you for your chosen career.

Grad student dogGraduate Studies

Students have a variety of options to pursue masters and doctoral degrees. Many of these have very specific background requirements, so we suggest exploring the individual programs for academic guidelines.

CTLLCenter for
Learning & Leadership

The CTLL is a student, faculty, alumni and industry partner collaboration for high quality learning and leadership beyond the classroom.


Inspiring Teamwork - Arron Carter pic

Inspiring Teamwork – Arron Carter

It started with a car, a ’69 Corvette Stingray to be exact.

When Arron Carter, the director of the Washington State University Winter Wheat Breeding Program, was in high school his agricultural teacher had a ’69 Corvette Stingray. Every year this teacher would let his favorite senior take the car to senior prom. Carter had never taken an agriculture class before, but he knew he wanted to drive that car.

“Well, if I’m going to be the favorite senior,” Carter said to himself, “I’d better start taking some ag classes.”…

Read More: Inspiring Teamwork – Arron Carter


CAHNRS Office of Research

Agricultural Research Center

Mission Statement

The goal of the Washington State University CAHNRS Office of Research is to promote research beneficial to the citizens of Washington. The Office of Research recognizes its unique land-grant research mission to the people of Washington and their increasing global connections. The CAHNRS Office of Research provides leadership in discovering and applying knowledge through high-quality research that contributes to a safe and abundant food, fiber, and energy supply while enhancing the sustainability of agricultural and natural resource systems.

Featured Research

sliced pear

Research for specialty crops boosted by $1.7 million

More than $1.7 million was awarded to Washington State University for specialty crop research including berries, potatoes, grapes, tree fruit, onions, carrots and Christmas trees.
Western bluebird with cricket. Photo by flickr user Kevin Cole.

Weighing the benefits, risks of wild birds on organic farms

Washington State University researchers will help organic growers protect human health by assessing the risks and benefits of wild birds on organic farms. Researchers received nearly $2 million from the USDA Organic Research and Extension Initiative to conduct the study.
Moyer Testimony 9.29.15

VIDEO: Jim Moyer testifies on specialty crop research before House Agriculture Committee

Jim Moyer, associate dean of research for CAHNRS and director of the Agricultural Research Center at WSU, presented specialty crop research innovations in Washington, D.C. this fall.
Winter Wheat May 2014 by McFarland

‘A quiet crisis’: The rise of acidic soil in Washington

Gary Wegner first noticed the problem in 1991, when a field on his family’s farm west of Spokane produced one-fourth the usual amount of wheat. Lab tests revealed a surprising result: the soil had become acidic.

Study: Small railroads important but costly to upgrade

More than half of Washington’s short-line rail miles aren’t up to modern standards, according to a recent study by the Washington State Department of Transportation and the Washington State University Freight Policy Transportation Institute.
A grizzly bear with her cubs at the WSU bear center.

Single hair shows researchers what a bear has been eating

By looking at a single hair, U.S. and Canadian researchers can get a good idea of a grizzly bear’s diet over several months.

CAHNRS Office of Research

Hulbert Hall 403
PO Box 646240
Pullman, WA 99164-6240
PH: 509-335-4563
FAX: 509-335-6751

Alumni & Friends

Holiday Hours & End-Of-Year Giving

It’s that time of year again—time for sharing merry moments with family and friends. As you prepare for the holidays, consider these year-end giving tips below. We know how important the last few days of 2015 will be for meeting tax deadlines, and we are here to help make the process as easy as possible.

Please note the WSU Foundation’s hours of operation through the end of the year:

Dec. 2 – Dec. 23: Normal operation (8:00 a.m. to 5:00 p.m.)

Dec. 28 – 31: Although Washington State University and the WSU Foundation will be closed, WSU Foundation gift accounting and gift planning staff will be available by phone from 8:00 a.m. to 5:00 p.m. throughout this week. If you would like to give a gift of appreciated stock or discuss your year-end giving plans to benefit WSU, please call 1-800-448-2978.

Making a gift online using the WSU Foundation’s secure site is an easy way to make your year-end gift using a credit or debit card any time, day or night. Note: Online gifts may be made as late as 11:59 p.m. on Dec. 31 to receive tax credit for 2015.

Thank you for your generous support of Washington State University throughout the year. Have a wonderful holiday season!

Year-end Giving Tips:

Remember, only gifts made by Dec. 31 can help reduce your 2015 taxable income. Please keep the following in mind and consult your tax advisor for specific details.

To Receive 2015 Tax Credit:

  • Make sure your gift is dated and postmarked no later than Dec. 31, 2015.
  • Complete your online gift on or before 11:59 p.m. (PST) on Dec. 31, 2015. We accept Visa, MasterCard, and American Express.


The date you deliver or mail your donation is generally recognized as the gift date for tax purposes. Please note, the date on the actual check or money order is not recognized by the IRS as proof of your intent to give on a particular date. Gifts by check or money order may be mailed to:

WSU Foundation
PO Box 641927
Pullman, WA 99164-1927

Note: Gifts may be hand-delivered to the WSU Foundation Town Centre Suite 201 during hours of operation.

Credit Cards:

The date your account is debited is considered the date of the donation. In order to receive a 2015 charitable income tax deduction, credit card gifts must be processed against your account in 2015. Please make sure to make your gift online using your Visa, MasterCard, or American Express.

Have your stocks gone up in value this year? Consider making a simple and tax-wise gift of appreciated stock. Please note that mutual fund shares may take several weeks to transfer, and the gift is not considered complete until the shares are received in the WSU Foundation’s account. To give the University stock or discuss your year-end gift to WSU, please call 1-800-448-2978.

Contact Us

CAHNRS Alumni & Development
PO Box 646228
Pullman, WA 99164-6228
PH: 509-335-2243

Faculty & Staff

Important Dates and Deadlines


A-Z Index of Faculty and Staff Resources:

  • Click letters to sort alphabetically
  • Click individual items to view or download

Contact Dean’s Office:
Hulbert 421
PO Box 646242
Pullman WA 99164-6242

Lisa Johnson:
Assistant to the Dean
Hulbert 421C
PO Box 646242
Pullman WA 99164-6242

How many varieties of wheat has WSU developed?



Sentence or two with more info about the subject.