Skip to main content Skip to navigation

WSU’s Voice of the Vine: Brains to Grapes, Wine in Provence, Inmates as Researchers, and Blackleaf in Grapes

Posted by | October 23, 2014

October 2014

From brains to grapes

Three months ago, Berenice Burdet was in Argentina, studying the intricacies of the human brain. Now, she is in central Washington, studying something slightly different: sugar transporter genes in wine grapes.

“Before this I was working with brains and rats. Now, I’m working with berries,” said Burdet, a postdoctoral research associate at the WSU Irrigated Agriculture Research and Extension Center in Prosser. “The physiology, the anatomy — everything is different.”

Berenice Burdet
Berenice Burdet

The transition from neurobiology to viticulture was difficult, but it was something she really wanted to do, Burdet said. In Argentina she visited vineyards and, through her family, became familiar with the world of wine.

Burdet’s passion for viticulture was present throughout her neurobiology studies. After receiving a doctoral degree in neurobiology from the University of Buenos Aires, Burdet attended a few enology courses through the Argentina Wine School. After that, she was hooked.

“I was passionate about it,” she said. “I could really see myself working in viticulture and enology.”

For her doctorate, Burdet studied how exposure to stress affected the brains of rats. It isn’t direct, or easy, to apply results found in rats to humans, she said, and therefore it can take many years for findings to become applicable. When Burdet turned to viticulture, she found that real-world applications of research occurred more quickly.

“In this field, in just a few years of research you can see the result and find the ‘solution,’” she said. “You can help improve the harvest and fruit quality because you have constant contact with the growers and you know the problems they face.”

With no professional viticulture experience and two open offers to continue her work in neurobiology, Burdet went looking instead for a research opening in viticulture and enology. Last year she attended a microbiology seminar in Seattle, during which a speaker mentioned Markus Keller, a scientist and professor of viticulture at WSU. After reading Keller’s papers and book, she decided to approach him about a possible research position.

“When I contacted Keller, he gave me a few suggestions on where to begin my viticulture research,” Burdet said. “He knew what he wanted to see from me, based on my background in molecular biology.”

Keller thought Burdet would be a great match for the research team in Prosser.

“I look for diversity, not in just the traditional sense, but also in terms of educational background and expertise,” Keller said. “I look for people who can think outside the box and who may potentially challenge the status quo in our field of research.”

“I was very lucky to find Markus,” Burdet said. “I am very grateful for the opportunity he gave me.”

Dispelling myths

Burdet’s entry into viticulture involves investigating a common misconception in the wine industry: that more rain or irrigation close to grape harvest must increase the berry size, diluting the sugars and tannins and possibly “cracking” the berry, that is, breaking the berry skin.

But, fruit growth and ripening depend on supplies of both water and sugar, not just water. This myth, and the lack of evidence to support it, inspired Burdet to study how water flow affects sugar levels in grapes during ripening.

Sometimes water in plant tissue can flow backward when plant water levels are low or when temperatures and evaporation rates are high. This can cause grapes to lose their stored sugars, possibly affecting the ripening process, Burdet said.

“We think that the sugar that moves out of the grapes may be recaptured in the pedicels,” Burdet said. Pedicels are the small stems that connect the grapes to the cluster, she explained.

Scientists have already identified sugar transporter genes in the leaves, roots, stems, and leaf stems of grapevines, she said. Her goals, then, are to find out what role these transporter genes play during ripening and to see how grapes retrieve the sugars lost from water movement.

Looking forward

Burdet has only been working in Prosser a short time, but she is enjoying the challenges of her new direction.

“I am reading all the time because everything is so new for me,” Burdet said. “I want to learn and also take the opportunity to interact with the other researchers on my team.”

She also wants to learn more about enology and, perhaps even start making her own wine.

—Emily Smudde

Springtime and wine in Provence

Does wine education and Provence sound like an enticing combination? If so, then you might be interested in signing up for the Southern France Winery and Vineyard Tour offered by the WSU Viticulture and Enology Program next April 19-May 1, 2015.

Vineyards in Provence
Vineyards in Provence

Join Viticulture and Enology Program Director Thomas Henick-Kling on a 12-day tour that will be based in the beautiful and historic city of Aix-en-Provence. From there, you will travel to wineries and vineyards in some of the most celebrated wine regions of the Southern Rhone valley including Chåteauneuf du Pape, Bandol, and Hermitage, where you’ll go behind the scenes with the winemakers and grape growers. You will also spend time strolling through the medieval villages of Avignon and Arles, and visiting the exciting coastal towns of Monaco and Monte Carlo.

This tour is sure to be not only educational, but rich with culture, wonderful food and wine, and many memorable experiences.

Visit http://wine.wsu.edu/education/certificate/international-winery-tours/southern-france for the full itinerary and trip details. You can also contact Theresa Beaver for more information at tbeaver@wsu.edu.

 

Inmates as ad hoc research assistants

Most spider mite research projects involve the tedious work of counting spider mites—peering down a microscope to count tiny specks on leaves.

Some would even call it cruel and unusual punishment. But a Washington State University researcher has found a workforce that enjoys the monotonous work, and he’s even saving money for the state’s grape industry.

One of the biggest expenses in spider mite research is the cost of counting and recording mites in the laboratory from collected leaf samples. It’s a task usually assigned to research or lab technicians, and one that WSU’s David James did early in his career. “Technicians don’t want to do it,” he said of the boring work that involves sitting hunched over a microscope for hours. Read more of this story in Good Fruit Grower.

 

Blackleaf in Washington Concord grapes

The summer of 2014 was exceptionally hot and sunny. Given these conditions, it is no wonder that reports of Concord blackleaf have been rolling in faster than a lower valley dust storm. In some cases, blackleaf has not been limited to juice grapes, there have also been reports of it on some wine grapes in certain locations.

In order to understand how to potentially manage or prevent blackleaf, we have to understand what it is and what it is not. It is not a nutritional deficiency. All of those old recommendations for applying potassium fertilizer to alleviate symptoms? Throw them out. It is not a result of mite feeding. Mites will cause a more browning and bronzing of leaves; and they can be controlled with a miticide. Spraying a miticide will not alleviate blackleaf. It is not a disease; not powdery mildew, not Grapevine leafroll.

Image of blackleaf on Concord grape leaves
Image of blackleaf on Concord grape leaves

Blackleaf is a physiological disorder that results in the degradation of chloroplasts (cellular structures that conduct photosynthesis) and death of epidermal cells (the outer “skin” of a grape leaf). This degradation and death is caused by exposure to excessive UVB sunlight. Specifically, in blackleaf, the damage is a result of exposure to UVB when the leaves are not fully mature and therefore lack the waxy cuticle and build-up of sunscreen compounds that would naturally protect the tissue from damage.

In Washington, most of the damage that is seen in Concord vineyards as “black leaves” in September, was actually from damage that was initiated in late June and early July. This is why blackleaf tends to be a bigger problem during years with reduced cloud coverage during those months. The damage takes time to fully manifest itself and display the “black leaf” symptoms. It is akin to the delayed muscle pain felt when starting a new sport or exercise regime.

Why do some blocks of Concord grapevines display severe symptoms of blackleaf when adjacent blocks have very little? Drought stress has been implicated in exacerbating blackleaf in Concord. Drought stress reduces vine transpiration, which in turn, can result in superheating of leaf tissue exposed to the sun. This high heat exposure can further damage chloroplasts and cells, accelerating the damage to the leaf tissue. As such, vineyards that experienced water stress do risk having more severe blackleaf symptoms. Water stress only enhances symptom development in vineyards that have already suffered from blackleaf damage, it does not cause it.

There are no current commercially acceptable techniques for preventing blackleaf in Concord vineyards. However, in years with few cloudy days and warm temperatures, the severity of blackleaf may be reduced with appropriate management of vine water stress.

For more information on blackleaf and potential ways to reduce symptoms, please see WSU Extension Publication EB0745, Blackleaf in Grapes (Olmstead et al. 2005).

This story originally appeared in the Fall 2014 issue of WSU’s Viticulture and Enology Extension News.

—Michelle Moyer