Genes in Storage

Husband and wife dig into what genes lead to longer potato storability

Published online: Nov 29, 2017 Articles Tyrell Marchant, Editor
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This article appears in the December 2017 issue of Potato Grower. 

One would hardly consider Nevada to be potato country. Livestock is far and away the agricultural king in the Silver State, and all other commodities bow down before it.

But in a lab at the University of Nevada, Reno, work is being done that researchers believe could eventually prevent the loss millions of tons of potatoes each year in the U.S.

With the help of a $1.37 million grant from the National Science Foundation (NSF), husband-and-wife team Dylan Kosma and Patricia Santos hope to discover, on a genetic level, ways to mitigate—if not eliminate—tuber loss in storage.

“Most vegetables are sent straight to the fresh market, but it’s different with potatoes,” says Kosma, a biochemist and molecular biologist. “I’ve calculated that if we can improve storage losses even by 5 percent, it’s in the hundreds of millions of dollars.”

The bottom line for growers and shippers is what matters most to Kosma and Santos as they look into these issues. It’s a mindset Kosma says has been drilled into him since his earliest days of research, when he was working under plant scientists Mike Pollard and John Ohlrogge at Michigan State University

“Universities are public institutions,” says Kosma. “We’re basically civil servants; at least we should be. [Ohlrogge] told me, ‘If you’re not doing something to help people, you shouldn’t be doing science.’ That’s really resonated with me ever since.”

The current NSF-funded project at the Kosma-Santos lab is focused on understanding the genetic reasons some potato varieties store better, for longer periods of time, than others—a question that has plagued the chip industry for years. Once the team understands that genetic basis, they will incorporate that information into a breeding program to develop a variety with all the most desirable traits for chipping as well as for profitable long-term storage. They are currently working with Atlantic and Snowden, though other varieties will likely be studied over the four-year course of the grant.

Of particular interest to Kosma and Santos is the wound-healing process and the role suberin—the fatty polymer that makes up a large chunk of potato skins—plays. Kosma compares suberin as the rebar inside a concrete structure. The waxes in potato skin may be what keep microbes out, but suberin is the framework that allows the skin to hold up to the beating it takes. Higher levels of suberin allow wounds to heal more quickly, which should lead to less loss in storage.

“If you don’t fortify that skin, the potato is just a big ball of starch,” Kosma explains. “Microbes love sugar and starch. The only thing between that starch and the pathogen is the skin—it’s like a plastic wrap that keeps good things in, including water, and the bad stuff out.

“The plan is to find a specific gene we’re looking for that aids in suberin production and wound healing, then breed that gene into new varieties. Nobody has made a connection before between the genes we’re working on and storability.”

Neither Kosma nor Santos is an Extension researcher, but they strongly feel their work can only be truly successful in collaboration with growers and other allied members of the potato industry. While the majority of the work on their current project will indeed be performed in the lab, they realize that no amount of lab work will make a difference without practical application. To that end, they have made a concerted effort to reach out to and communicate with growers, most notably nearby Winnemucca Farms. They hope growers and researchers interested in this kind of research will reach out to them as well with their own concerns about potato storage.

“Most of our stuff is in the lab,” says Kosma, “but we’re really trying to connect with the ag community on the farm.”

Also working with Kosma and Santos and their team of students are UNR molecular biologist Karen Schlauch, along with potato breeder Dave Douches and pathologist Ray Hammerschmidt, both at Michigan State University. It’s a crack team Kosma and Santos are excited to work with, and they expect big things from the partnership. 

“I think most people are approaching these issues through cultural practices, and they should,” says Kosma. “But we’re hitting it from the genetics and breeding side. Our research may not result in that 5 percent improvement right away, but it should chip away at it.

“I want growers to talk to me. I want my research to be directed toward real ag problems.” he continues. “It’s really important for us that our science does things that are going to matter.”


Dylan Kosma can be contacted at