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Searching for Solutions on a Long-Term Mission
Wednesday, January 1, 2025
filed under: Disease
An Interview With USDA-ARS Research Plant Pathologist Bill Underwood
Photo courtesy of Bill Underwood
Editor’s Note: William (Bill) Underwood joined the USDA Agricultural Research Service’s sunflower unit in Fargo, N.D., in 2015. As its new research plant pathologist, he succeeded the retired Tom Gulya, who had held that position since 1978. To familiarize growers and industry with Bill and his important work, we asked him to respond to these questions.
Where did you grow up . . .where did you earn your degrees (and in what fields) . . . and where did you work prior to joining the ARS team in Fargo?
I grew up in Madison, Ind., about 40 miles up the Ohio river from Louisville, Ky. I got my B.S. degree in Biology from Indiana University and then a Ph.D. in Genetics from Michigan State University. Prior to joining ARS in Fargo in 2015, I was a postdoctoral fellow and then research scientist at UC-Berkeley.
What was your initial focus when starting with ARS at Fargo? How has that changed/modified through the years?
My assignment with ARS is split between the sunflower group and the National Sclerotinia Initiative, so I have always had a significant focus on Sclerotinia diseases, including research on both the plant side of the interaction as well as on the biology and pathogenicity of the causal fungus itself. Over time, my group’s work has shifted toward a greater emphasis on the plant side of the interaction, in part because I feel this emphasis has more potential to lead to solutions of value to sunflower growers.
Where do we stand with Sclerotinia? Any breakthroughs that you would classify as particularly significant?
The National Sclerotinia Initiative was started in 2002, so we’re coming up on 23 years of this program. Research on diseases caused by this fungus can probably best be described as “plodding,” for reasons that I’ll discuss more below. I think at this point, if there is going to be any “silver bullet” sort of breakthroughs, they’ll probably be something that kind of comes out of left field, so to speak.
Sclerotinia has been a “boogey man” for sunflower producers for several decades. What are the main reasons (multi-gene traits, etc.) it has been so challenging?
The fact that resistance to Sclerotinia is a complex trait, controlled by many genes, is certainly one of the reasons that progress on improving resistance in sunflower and other crops is slow. However, if this aspect was the only impediment, it wouldn’t be so bad.
The major roadblocks that we need to find a way to circumvent are that resistance to Sclerotinia is correlated with late flowering and maturity — and also associated with generally poor plant fitness that results in poor agronomic performance for highly resistant lines.
As noted above, my research program has shifted over time toward working to understand these relationships between resistance to this pathogen and flowering time or plant fitness. My hope is that we can improve our understanding of the genes and mechanisms governing resistance to this disease to the point where we can find ways to achieve high levels of resistance without the undesirable tradeoffs in plant fitness and flowering time; but whether this will be possible remains to be seen.
How has the advancement of biotechnology (use of markers, etc.) contributed to your ability to progress on Sclerotinia and other diseases? Also, please give an example or two (in layman's terms).
The advances in DNA sequencing technology in the past 10-15 years have completely transformed our ability to study complex disease resistance traits like resistance to Sclerotinia and Phomopsis. Before the extraordinary improvements in DNA sequencing, we could only vaguely identify large genomic regions associated with resistance, and had essentially no hope of identifying actual genes involved in the plant’s response to disease.
Now, my group is beginning to identify specific genes contributing to Sclerotinia resistance in the model plant Arabidopsis thaliana and to study their functions. I am hopeful that these developments will allow us to take what we learn in the more tractable model organism and apply it to sunflower to address the roadblocks to improving resistance that I discussed above.
What other diseases do you focus on?
Over the past five years, my group has begun to focus more on Phomopsis stem canker, as this disease has increased in importance for U.S. growers. Resistance to this disease is also quantitative, like resistance to Sclerotinia; but I am more optimistic that we can achieve good levels of resistance to Phomopsis in a reasonable time frame, based on the results we’ve seen so far.
Obviously your work is a very long-term investment, both for ARS and for you personally. What are some of the key “personal requirements” of a long-term basic researcher such as yourself (e.g., patience, curiosity, tenacity). What mindset do you need to keep focusing on research that may not yield benefits for the producers for several years, if not decades?
Certainly, research to improve resistance to Sclerotinia has been and continues to be a long-term proposition. I would say that all the traits that you mentioned are necessary. I also think it’s important to try to mix in some projects and research directions that might at least have the potential to be impactful in a shorter time horizon.
For large-scope, complex challenges like Sclerotinia diseases, my mindset is to focus on answering specific research questions that I think will meaningfully advance our efforts to find solutions.
Finally, I always try to keep in mind that scientific discovery is not a linear or predictable process. You never really know where the next breakthrough will come from.
Please speak to the importance of basic research — as opposed to a commercial program where there is more emphasis on economic return from research.
My scientific background before joining ARS was very much rooted in basic research, so I’m really a true believer in the long-term value of this style of scientific inquiry. Although basic research may sometimes seem highly esoteric and to present no clear path toward a useful product or technology, this type of research in time can lead to major breakthroughs.
A great recent example comes from the lab where I did my Ph.D. research. My doctoral advisor, Sheng Yang He, and his research group have studied the function of a specific protein from a bacterial plant pathogen that is important for the bacteria to cause disease for over three decades now. At times this research seemed to be going nowhere; but recently they were able to determine the function of this protein, and this discovery also led to the identification of synthetic molecules that could block its activity and thus suppress disease. These synthetic molecules are now being commercialized for suppression of numerous bacterial plant diseases.
How do commercial hybrid seed companies interact with you — and access your achievements (i.e., germplasm releases)?
Our sunflower research group here in Fargo has generally focused on developing germplasm resources with particular traits or combinations of traits for public release – and, in parallel, providing information such as molecular markers to allow seed company breeders to efficiently utilize these traits and materials.
Where do you see your research program heading in the next year or two – and, as well, further down the road?
We have determined over the past few years that overall resistance to Phomopsis is likely comprised of several distinct forms of defense operating in different tissues (leaves and stems). Our focus now is on genetic characterization of these distinct forms of resistance; and, over the longer term, we will try to determine how best to combine these resistance traits to hopefully achieve strong and durable resistance to this disease.
For Sclerotinia, we have parallel research tracks focused on genetic mapping of resistance in the most highly resistant sunflower lines, alongside basic research using Arabidopsis to try to unravel the relationships between Sclerotinia resistance, delayed flowering and reduced plant fitness. I can’t necessarily foresee the point at which these two tracks will come together; but, as I noted above, basic research tends to produce unanticipated discoveries that change the way we approach problems. I’m hopeful that will be the case with this stubborn disease.