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USDA Pathologist Calls it a Career

Friday, February 7, 2014
filed under: Research and Development

Some people have schools, highways or government buildings named after them. For Tom Gulya, it’s a fungus. In 2011, Australian sunflower plant pathologist Sue Thompson discovered three new fungal species that cause a severe stem canker — and named one of them Diaporthe gulyae as a tribute to her U.S. counterpart. (“She also describes it is the ‘most aggressive’ of the three,” he notes with a trademark quip.)

Gulya knows that very few people would view having a fungus bearing their name as a career highlight. But in the world he has inhabited for the past four decades — that of a research plant pathologist — it is a distinct form of professional compliment.

Gulya retires in early February from the USDA-Agricultural Research Service following more than 35 years as plant pathologist with the Fargo, N.D.-based ARS Sunflower Research Unit. It’s a career he certainly did not envision while growing up in northern New Jersey; but it’s likewise one about which he has no regrets. It has taken him from the laboratory to the greenhouse, from field research plots to growers’ sunflower fields, from innumerable one-on-one meetings with USDA, university and industry colleagues to international meetings on several continents. And it all has focused on gaining a better understanding of — and helping to rein in — the diseases that affect sunflower producers’ bottom line and the welfare of the industry in general.

Tom Gulya’s journey to Fargo began at the University of Delaware, where he earned his bachelor’s degree in agriculture in 1970. Following a “three-year, all-expense-paid vacation compliments of Uncle Sam,” Gulya headed west to Iowa State University, where he earned M.S. and Ph.D. degrees in plant pathology, focusing on diseases of soybean and corn, respectively. When it was time to find a job, he had three interviews: one with a private seed corn company, another for a corn pathologist position at North Carolina State University — and the USDA sunflower position in Fargo.

“This one was intriguing,” he recalls, “and it also had an additional factor in that one of my office mates at Iowa State was Rama Urs, who had gone to work for Dahlgren & Company at Crookston, Minn. That wasn’t a major factor in my decision, but it helped both of us in the end. Rama was one of the very few industry pathologists, so I benefited from his experience and our collaborations.”

Gulya admits to knowing very little about sunflower upon taking the USDA job in 1978. (Longtime sunflower entomologist and California native Larry Charlet, who retired in 2012, joined the Fargo ARS team on the same day.) “I think the situation back in ’78 was pretty much like it is now,” Gulya says. “You take anybody from a university outside of North Dakota or South Dakota, and they’re barely aware that sunflower is even a crop. When I left Iowa State, one of the botanists said to me, ‘I want you to learn all about sunflower diseases, then come back to Iowa and tell us how to kill them.’ It was a facetious remark, but in places like Iowa, wild sunflower was a noxious weed.”

The New Jersey native’s family and friends were scratching their heads a bit, too “North Dakota was viewed as one step away from the edge of the world. To people on the East Coast, the ‘Midwest’ means Ohio. The Dakotas were off their radar screen,” Gulya remarks.

“But I’ve never regretted moving to North Dakota — not one bit.”

What were the predominant diseases confronting sunflower researchers, growers and industry as of the latter 1970s when Gulya came to Fargo? “Basically, the same diseases were present then as we have today; but they’re modified,” he replies.

Take downy mildew, for instance. “My predecessor, Dave Zimmer, worked on downy mildew,” Gulya notes. “But they had just one race of the fungus to deal with. They found one dominant gene, so it was easy to make progress with that disease.”

But fungi, like everything else in the natural world, are not static. “Within five years of my coming here, three or four new races of downy mildew were discovered,” Gulya notes. “For each of those, you need to find a new [resistance] gene, and the seed companies need to put that into their parental lines and make new hybrids. You can do that with one or two new races — but then it snowballed.”

Enter the seed treatment Apron®, which became registered on sunflower for control of downy mildew. “The seed companies said, ‘Wait a minute. We can spend a few dollars to treat a bag of seed, control this disease — and put that breeding effort on the back shelf so we can concentrate on other things.’ That’s basically what occurred until the late ’90s, when the fungus developed resistance to Apron. Then the industry said, ‘Maybe we do need genetic resistance’ ” to downy mildew.

Now, as of 2013/14, there are 20 different known races of downy mildew, Gulya says. “But Lili Qi (ARS molecular geneticist) has found two new genes that she has numbered ‘Pl-17’ and ’Pl-18,’ and there also are a couple unnumbered ones, bringing the total of genes for downy mildew control close to two dozen.”

Rust is a disease that comes and goes in importance — and then comes back again. “There we have resistance genes, and we now have registered fungicides,” Gulya points out. “If you don’t get complete disease control through genetic means, it’s good to have a second means of managing — like fungicides.” A key reason why there aren’t more sunflower fungicides, he adds, is the size of the market versus that of other larger-acreage and/or higher-value crops. “That’s why we’re always second or third, at best, on the registration label.”

Phomopsis was not even recognized in sunflower when Gulya joined the USDA in 1978. It was first identified in Europe in the mid-1980s and only later in the U.S. “Phomopsis went from being a real rarity to, right now, a much more significant disease,” he notes. “All diseases are influenced by weather. So as long as we have wet summers, Phomopsis is going to be a problem.”

Then there is Sclerotinia — the disease that has consumed more of Gulya’s time and energy than any other. Dave Zimmer had done some evaluating for Sclerotinia resistance if and when he found it occurring naturally in a breeding nursery. “But it was not too ‘intentional.’ If the disease occurred, they took notes on it.”

Gulya stepped up the effort. “We kept our eye out for growers’ fields that had Sclerotinia,” he recalls. “We’d then contact the grower, ask if we could rent some land — and establish disease nurseries where there already was a natural infestation.” That went on for about 15 years. “But I must have jumped around to six or seven different growers,” Gulya remarks, “because after you have a disease nursery on a field for two or three years, the grower tends to say, ‘You know, the longer you stay here, the longer that field isn’t going to be worth “diddly” to me.’ ”

After the National Sclerotinia Initiative — an ARS-led consortium encompassing seven different crops impacted by this disease — was established in 2000, more funds became available for improved and expanded field screening for Sclerotinia. The Fargo ARS program now grows the fungus in large quantities, which then allows for the inoculation of specific fields so that numerous sunflower lines can be screened for tolerance or resistance to the stalk rot form of Sclerotinia. Also, nurseries with automated mist irrigation systems have been used for several years at Carrington, N.D., and Staples, Minn., for the purpose of screening lines for head rot resistance. Misting systems are essential for effective head rot screening since moisture is central to the disease’s presence and severity.

What does the longtime USDA plant pathologist believe to be the greatest strides forward in sunflower disease management during the past three decades — and, simultaneously, what does he view as the biggest challenges going forward?

“Sclerotinia” is his one-word answer to both parts of that question.

“As a research community — public and private combined — I think we’ve made big strides” in dealing with Sclerotinia, Gulya states. “If we were to take a hybrid grown in the 1980s and put it out against a current hybrid, not only would the current one have better oil profile, better yield and better tolerance to a lot of environmental stresses; it also would have much better tolerance or resistance to Sclerotinia.”

But, nothing is “immune,” Gulya stresses. And none of today’s sunflower hybrids can be considered “totally resistant” to Sclerotinia. “Sclerotinia will continue to be a big challenge,” he affirms. “It’s a question of how much more we can improve the resistance without sacrificing other necessary components like yield and oil content.”

The biggest obstacle — along with its presence in two forms (stalk rot and head rot) — in breeding for Sclerotinia resistance is the multi-gene nature of this disease. Unlike downy mildew, rust or Verticillium wilt, where a single gene can provide resistance to a race of the fungus, Sclerotinia resistance is controlled by many genes, each making small contributions — which, of course, really complicates the discovery and incorporation of genetic resistance.

In recent years, however, the notable progress made in field trials and misting nursery screenings has been bolstered by the employment of marker-assisted breeding. Molecular geneticists and plant breeders have become increasingly adept at locating and identifying markers (tiny pieces of DNA located in or near a gene) for specific traits such as Sclerotinia resistance. Simultaneously, they are better able to “plug in” the desired traits into breeding populations.

“When working with complicated traits like Sclerotinia that are controlled by many genes, you need not just one or two markers; you may need two dozen, three dozen or even more,” Gulya points out. “So this technology is really helping us to find resistance more quickly, more efficiently.”

Still, the plant pathologist in him offers this caution: “As soon as we have all the tools necessary to say we can very efficiently find resistance, Mother Nature will say, ‘I’m going to throw another fungus at you now.’ Nothing in nature is static.”

Traditional plant pathology won’t go away, Gulya adds. “But it is being — and needs to be — supplemented by these newer molecular tools. There’s a lot of money and effort being poured into getting more markers, doing SNP* work. In the not-too-distant future, we may not need to rely exclusively on actual disease testing. We won’t need to screen 1,000 lines in a greenhouse to tell [USDA sunflower geneticist] Brent Hulke which ones are resistant against downy mildew, for example. Instead, Brent or geneticist Lili Qi can take some leaf tissue, grind it up, extract the DNA and say, ‘This line has the marker for the resistance gene; this one does not.’ That’s the wave of the future.”

As he looks back on three and a half decades of working to help sunflower growers and industry better manage this crop’s diseases, Tom Gulya says his career satisfactions, while many, basically boil down to two things: personal relationships and feeling he has made a contribution to the overall goal of improved disease control.

“I will miss the individuals I’ve worked with —not just because we work together and accomplish something, but also the personal relationships. My family has come to know a lot of people I work with, both domestically and internationally.”

His work community has embraced many individuals: fellow ARS unit members, seed company plant breeders, sunflower growers, university pathologists, industry personnel and international colleagues. “If you’re a researcher, you want challenges,” Gulya affirms. “And sunflower certainly has provided challenges. As long as you have able co-workers and enough funds to make some progress, that’s where job satisfaction comes from.”

That — and having a fungus named after you. “I would have preferred someone found a beautiful edible mushroom and named it after me,” Gulya smiles. “But it’s something of significance for the sunflower community. So for better or worse, I will ‘live on in infamy!’— Don Lilleboe

* SNP stands for “single-nucleotide polymorphism,” a technology that allows for unprecedented analysis of breeding populations, contributing to much faster and more-accurate identification and use of markers for the incorporation of desired traits like disease resistance into breeding lines. USDA sunflower geneticist Brent Hulke is heading a sunflower SNP effort that also encompasses commercial breeding programs.

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