- Waterhemp, a common agricultural weed, has become increasingly resistant to atrazine and other herbicides.
- Waterhemp uses a class of enzymes known as GSTs to detoxify herbicides, but the exact GST responsible for atrazine resistance was not known until recently.
- University of Illinois researchers used molecular methods to identify a gene for GST-based atrazine resistance.
- Knowledge of the gene will allow for easier diagnosis and could lead to the development of more targeted control options.
URBANA, Ill. – Waterhemp has been locked in an arms race with farmers for decades. Nearly every time farmers attack the weed with a new herbicide, waterhemp becomes resistant to it, reducing or eliminating the efficacy of the chemical. Some waterhemp populations have evolved resistance to multiple herbicides, making them incredibly difficult to kill.
Adding to the challenge is the fact that waterhemp can evolve resistance in at least two ways. In target-site resistance, a gene mutation changes the protein that the herbicide is designed to attack. With an ill-fitting protein binding site, the herbicide becomes ineffective. The plus side of target-site resistance is that it is relatively easy to identify using standard lab procedures.
Metabolic resistance is a different beast. Plants use any one of hundreds of possible enzymes to detoxify the chemical, rendering it useless. Although University of Illinois weed scientists Dean Riechers, Rong Ma, and Josh Skelton recently developed a quick and easy test for metabolic resistance, they still had no way of knowing which enzyme was responsible.
“We think we found the needle in the haystack,” Riechers says.
Riechers and his colleagues focused on metabolic resistance to atrazine, a chemical that has been used for decades and is still sprayed on approximately 80 percent of the corn acreage in the United States, despite increasing resistance and concerns about environmental impacts.
From previous research at U of I, the team knew that resistant waterhemp metabolizes atrazine with a class of enzymes known as GSTs. “Plants are known to have anywhere from 50-120 GST genes. We wanted to know if resistance was coming from just one of those, and whether we could find it,” Riechers says.
Former graduate student Anton Evans isolated candidate GST proteins from waterhemp and looked at their expression in resistant and sensitive plants. One of the GST proteins was extremely abundant in resistant plants, but almost nonexistent in sensitive plants. Graduate student Sarah O’Brien looked more closely at the gene encoding that GST protein, and, in particular, at its variants or alleles. She noticed that when two dominant alleles for this gene were present, it took more than 14 times the recommended atrazine rate to damage the plants.
“The heterozygous plants – those with just one copy of the dominant allele – had much higher injury. In an experiment with four or five heterozygous plants, two or three would die and the others were stunted and had a lot of dead tissue. But the homozygous resistant plants – those with two copies of the dominant allele – almost looked like they hadn’t been sprayed,” O’Brien says.
“Plants without the dominant allele just got hammered, even at low herbicide application rates,” Riechers adds.
This evidence, along with more detailed molecular data, gives the team confidence that they have discovered something unique. “This may be the only case where we’ve actually found the gene responsible for metabolic resistance in a broadleaf weed, as opposed to target-site resistance,” Riechers explains, “for any herbicide.”
Going forward, the test for this gene will be similar to the test for target-site atrazine resistance. The new information also could be used by industry to develop new chemicals to control waterhemp.
“As long as we know the gene, you could potentially knock it out and make the plant sensitive again. You could design a GST-inhibiting chemical that’s specific to this one GST,” Riechers says.
The article, “Biochemical characterization of metabolism-based atrazine resistance in Amaranthus tuberculatus and identification of an expressed GST associated with resistance,” is published in Plant Biotechnology Journal. Anton Evans Jr., Sarah O’Brien, Rong Ma, Aaron Hager, Chance Riggins, Kris Lambert, and Dean Riechers contributed to the paper. Syngenta U.K. supported the project.
STRONG Kids program receives additional support from the National Dairy Council
URBANA, Ill. – Exploring how multiple factors contribute to the development of childhood obesity, the Family Resiliency Center’s STRONG Kids Program recently received an additional $548,275 of funding from the National Dairy Council (NDC) to extend its current research project, STRONG Kids 2, through 2019.
STRONG Kids 2 is one of the first comprehensive research projects to explore how individual biology and dietary habits, including milk and dairy consumption, interact with the family environment to provide unique insights into the underlying causes behind childhood obesity. Originally, project participants were to be observed from birth to three years of age. The increased support from the NDC allows researchers to follow participants until they reach five years of age—a critical point for children as they become more vocal about their food preferences and spend more time in out-of-home care.
The increased observational time will be critical in providing a clearer picture of early childhood health. “We are already seeing important shifts in growth during the first year of life in this group of infants,” says the program’s co-director Barbara H. Fiese. “Being able to track these patterns into the preschool years will allow us to identify potential points of intervention to protect children against unhealthy weight in the early years. We are tracking the importance of breastfeeding, timing of introduction of solids, presence of dairy, and good sleep habits as predictors of healthy outcomes for these children. Being able to do so for five years is quite remarkable.”
The additional support has also allowed researchers to expand recruitment to ensure enough families are retained over the length of the study. The expansion of the participant pool and the length of time they are involved in the project is significant according to co-director Sharon Donovan. “Being able to expand the cohort and the length of the time that we are obtaining data are both important because they will ensure that we have sufficient statistical power to examine health and dietary changes over time a time,” Donovan says, “and we will be able to follow the children as they are transitioning from preschool or home to school.”
Project staff has worked hard over the past three years to recruit a cohort of expectant mothers throughout central Illinois to participate in the project. At present, the project has passed its recruitment goal of 450 participating families.
Over the course of the study, biological samples and measurements are collected from this cohort at intervals, and mothers are surveyed about weaning, dietary habits, and household routines, as well as children’s emotions, feeding styles, and milk and dairy consumption. The new funding allows researchers to enhance these measurements through added questionnaires and home observations to ensure they have a clearer picture of dietary intake. Says Donovan, “We’re able to add more home observations and 24-hour dietary recall measures, which will complement and extend upon the current measures of dietary intake in the cohort.”
Ultimately, the findings from STRONG Kids 2 will serve as the foundation for obesity prevention and intervention programs throughout the country.
Andres Ham studies impacts of minimum wage in Honduras
As part of the ACES International Graduate Grants research program, Andrés Ham, a PhD student in Agricultural and Consumer Economics advised by Dr. Kathy Baylis, traveled to Honduras to study the consequences of minimum wage policy in a developing country.
“Minimum wages in developing countries tend to be sizable, are less likely to be rigorously enforced, and labor markets are often segmented into formal and informal sectors with minimum wage policy only covering formal workers. Given that most developing countries implement minimum wage policies, understanding their consequences on labor markets is critical for economic growth, developing effective labor policy, and poverty alleviation,” says Ham.
While in Honduras, Ham consulted with the National Statistics Institute, the Director of Wages in the Ministry of Labor, as well as sources outside the government including employers’ and workers’ organizations, and various other stakeholders.
“Together these viewpoints provided a comprehensive understanding of minimum wages in Honduras from the perspective of government, employers, and workers. This insight allowed me to qualify my results and better explain my findings,” says Ham.
Considering formal and informal sector jobs, Ham’s findings suggest that the costs of increasing minimum wages outweigh the benefits in this developing country. “The policy implication is that setting high minimum wages has detrimental effects on labor markets, well-being, and compliance,” says Ham.
His research was featured in the World Bank’s Development Impact blog (link here: http://blogs.worldbank.org/impactevaluations/should-developing-countries-increase-their-minimum-wages-guest-post-andr-s-ham, was shared on social media by the World Economic Forum, and was reported by a local newspaper in Honduras.
The impact of Ham’s work continues:
“The exposure received by the study prompted the government, employers, and unions to verbally commit towards increased cooperation to help solve some problems with minimum wage policy in Honduras. Currently, I am assisting the Ministry of Labor to help design a formula to measure changes in worker productivity, a key input to decide minimum wage changes. This addresses one of several jointly identified priorities: a systematic way to decide annual increases in minimum wages, improving enforcement, and creating safeguards to mitigate the negative effects from minimum wage hikes,” says Ham.
Ham is one of twelve ACES graduate students who received funding as part of the third round of the Graduate Student International Research Grants Program.
The Office of International Programs is currently accepting proposals for the 2017 program; proposals are due March 6. Click here for more information.
Nematode resistance in soybeans beneficial even at low rates of infestation
- Soybeans with resistance to soybean cyst nematodes seem to have a yield advantage compared to susceptible varieties when SCN is present.
- Until now, scientists did not know what level of SCN infestation is needed to achieve the yield advantage.
- A new University of Illinois study shows that SCN resistance from the soybean accession PI 88788 offers yield advantages even at very low infestation rates.
URBANA, Ill. – Each spring, tiny roundworms hatch and wriggle over to the nearest soybean root to feed. Before farmers are even aware of the belowground infestation, the soybean cyst nematode silently begins to wreak havoc on soybean yield.
Fortunately, breeders have identified soybean varieties with genetic resistance to the nematodes and have used them to create new resistant varieties. As you might expect, resistant varieties yield more than susceptible ones when SCN is in the soil. But, until now, it wasn’t clear whether that yield advantage held up at low SCN infestation rates.
“The University of Illinois has been organizing a regional testing program of university-developed experimental soybean lines through funding from the United Soybean Board. In the last decade, we have collected data on agronomic performance, including yield, but also data on the resistance of the lines as well as on SCN pressure in the field. We’ve built up a massive dataset from these tests,” says University of Illinois soybean breeder Brian Diers.
By looking at 11 years of data from 408 sites around the Midwest, the researchers found that there was a yield advantage for SCN resistance even at low infestation levels—as low as 20 eggs per 100 cubic centimeters of soil. In environments with no SCN infestation, the team saw evidence of yield drag, where resistant varieties yielded slightly less than susceptible ones.
“But most fields in the Midwest do have at least some infestation,” Diers says. “So, in most cases, there’s little justification in planting susceptible varieties to avoid that potential yield drag.”
The most common source of SCN resistance is from a soybean accession known as PI 88788. It is well known that SCN is increasing in its ability to overcome 88788-resistance throughout the Midwest. The researchers wanted to find out if varieties with 88788-resistance are still able to produce high yields despite mounting pressure from nematodes.
Using the same large dataset, the researchers found that those varieties still provide at least enough moderate resistance to produce good yields. “For me, it’s a message to the soybean community that the sky hasn’t fallen, that 88788-resistance is, on average, working well in most fields,” Diers says.
Diers cautions that other sources of resistance, such as Peking or 437654, are better choices in fields where SCN is able to overcome 88788-resistance at a high level. However, he also notes that those varieties are harder to find.
“Farmers should rotate soybeans with a non-host crop such as corn, and also, if possible, with soybean varieties that have SCN resistance from alternative sources,” Diers suggests.
The article, “Impact of soybean cyst nematode resistance on soybean yield,” is published in Crop Science. The research was supported by the United Soybean Board.
2016 FSHN faculty awards and recognitions
The College of Agricultural, Consumer and Environmental Sciences at the University of Illinois has award-winning faculty in all of its departments. These faculty in the Department of Food Science and Human Nutrition are recognized for their excellence in teaching, research, outreach, and service at the university level as well as on the national and international stages.
What follows is an incomplete list of the awards and recognitions received by faculty in 2016.
Food Science and Human Nutrition
Karen Chapman-Novakofski Excellence in Practice Award, Academy of Nutrition and Dietetics
Jill Craft NACTA Educator Award, North American Colleges and Teachers of Agriculture
Justine Karduck Outstanding Abstract Award, Academy of Nutrition and Dietetics
Elizabeth Jeffery Dannon Institute Mentorship Award, American Society of Nutrition
Zeynep Madak-Erdogan Mary Swartz Rose Young Investigator Award, American Society of Nutrition and the Council for Responsible Nutrition
Elvira de Mejia Sheth Distinguished Faculty Award for International Achievement, Illinois International Program
Shelly Schmidt Campus Award for Excellence in Graduate and Professional Teaching, University of Illinois
See the full list for ACES at http://news.aces.illinois.edu/news/2016-aces-faculty-awards-and-recognitions.
NIFA’s Director of International Programs offers global perspective
Why should ACES engage globally?
This question was answered convincingly by Dr. Otto Gonzalez who serves as Director of the Center for International Programs at the USDA’s National Institute of Food and Agriculture (NIFA) when he spoke recently on campus as part of the ACES International Seminar Series.
Using four categories, Dr. Gonzalez explained the benefits of active international engagement:
- Trade and food safety
A great portion of our food comes from other parts of the world so by sharing science, we are also protecting ourselves.
“We want people to eat more fresh fruits and vegetables. This is one of USDA’s promotional messages. ‘Eat your colors - Fill half of your plate with fruits and vegetables’ – this is what we tell people. But even though we produce a lot here, half of our fresh fruits and nearly half of our vegetables are imported,” Gonzalez said.
The United States imports fresh and frozen fruits and vegetables from 64 different countries, he noted.
“We need to share our science, including techniques for diagnostics, prevention, and detection, with other countries so they can better protect against microbial contamination which ultimately protects us as well,” he urged.
- Emerging and reemerging diseases as threat to food safety
Plant and animal diseases often initiate elsewhere, so it is beneficial to address them before they arrive in the United States.
Gonzalez provided multiple examples of how diseases threaten our food safety. Wheat blast, which causes plants to be absent of seed, somehow made its way from Latin America to Bangladesh. And the cost of the 2013 Asian influenza in chickens amounted to $1 billion worldwide. “Not only are the birds lost, but faith in the industry is lost,” he said.
“In working with other countries we are able to share information and test out resistances in different areas of the world. Being able to protect ourselves from these emerging and reemerging diseases is a strong case for global engagement,” he said.
- Climate trends as a threat to food security
Uncertainties in climate are contributing to global food insecurity.
Using a color-coded map of the world, Gonzalez demonstrated that “The areas already most affected by food insecurity are also the areas being most affected by variabilities and uncertainties in climate.”
“Many of these areas are already dry, and the changes in rain patterns are further exasperating the situations,” he added. And droughts and lack of access to water often contribute to migrations, further compromising food security.
He noted that NIFA has already worked with Tanzania to develop a climate change resistance plan to adapt to the changing climate.
Much of the world’s conflict is rooted in a lack of resources.
“Another reason to engage with the rest of the world is to prevent conflict. Because so much of conflict is rooted in the loss of people’s livelihoods, often which are agricultural,” he said.
To conclude the first segment of his presentation, he said, “There are lots of good reasons to engage globally, but I’ve found these categories to be a handy way to summarize them.”
Opportunities for engaging with NIFA
Gonzalez next discussed how academics can use NIFA as a resource for international engagement.
He clarified that obviously a National Institute of Food and Agriculture is national in nature. In fact, he said only 2.6% of NIFA’s current projects have global engagement. He noted that at least five of these awards are based at the University of Illinois!
“NIFA supports global engagement that advances U.S. agricultural goals,” he clarified.
The flagship competitive grant for U.S institutions is the Agricultural and Food Research Initiative (AFRI) program. The NIFA website posts the AFRI calls at: https://nifa.usda.gov/afri-request-applications.
The site states that in Fiscal Year 2017, there will be seven Requests for Applications (RFAs): Foundational Program; Childhood Obesity Prevention Challenge Area; Climate Variability and Change Challenge Area; Food Safety Challenge Area; Sustainable Bioenergy and Biproducts Challenge Area; Water for Food Production Systems Challenge Area; and the Food, Agriculture, Natural Resources and Human Sciences Education and Literacy Initiative.
“International collaborations often show a greater impact, and you can write your partners into your proposal,” he noted. “The objective has to come back to a domestic objective,” he clarified.
Many of the points covered by Dr. Gonzalez about AFRI’s international partnerships can be found on this AFRI Q&A page: https://nifa.usda.gov/resource/afri-international-partnerships
He noted that NIFA has added several international partners to give U.S. researchers additional opportunities to work with international colleagues. NIFA and its international partners hope to issue more joint proposals in the future.
“We are not giving each other money; we are each funding our own researchers,” he said of the international collaborations.
Dr. Gonzalez said a way to collaborate with your former international students is to encourage them to apply for the Partnerships for Enhanced Engagement in Research (PEER) grants: http://sites.nationalacademies.org/pga/peer/index.htm
The Office of International Programs and the College of ACES were honored to have Dr. Gonzalez as a speaker and guest. During his visit, he was able to meet with several members of ACES administration, faculty, and students.
More about Dr. Gonzalez: Otto Gonzalez in February 2016 became the Director of the Center for International Programs at the NIFA. Prior to that he was a Special Projects Officer in the Office of Capacity Building and Development in the USDA Foreign Agricultural Service (FAS), based in Washington, D.C. with frequent travel, where for 19 years he led international technical assistance activities to build capacity in natural resource management, agriculture, and rural development. Afghanistan, Pakistan, and Central America are among the areas where Gonzalez has had projects. He earned his PhD in Natural Resources and Environment (focused in forest ecology) from the University of Michigan.
More about NIFA: https://nifa.usda.gov/
Chris Evans of NRES on Harvesting Maple Sap to make Syrup
Christopher Evans, Forestry and Extension Specialist with NRES, recently gave an interview about harvesting Maple Syrup and other activities related to late winter in the woods of Southern Illinois, which will be lighlighted at the annual Maple Syrup Festival on February 25th and 26th, 2017.
Here is a link to the interview: https://cpa.ds.npr.org/wsiu/audio/2017/02/MapleSyrupFestivalMP3SHORAirVersionFINAL.mp3.