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Iowa State University Research to Study Plant Responses to Pathogens
April 29th, 2010
AMES, Iowa — A U.S. Department of Agriculture scientist and his Iowa State University colleagues will partner with scientists from the United Kingdom to investigate how crop plants respond to pathogens through a new grant that includes an educational component for Iowa high school students.
The Iowa State group is led by Roger Wise, a research geneticist with the USDA’s Agricultural Research Service and a collaborating professor in the ISU plant pathology department. The work is funded by a $2.76 million National Science Foundation (NSF) plant genome grant to study the resistance of cereal crops to fungal pathogens.
In an earlier project, Wise and coworkers discovered barley genes that regulate defense against powdery mildew. The new project builds on those discoveries by addressing the molecular interactions that occur when the powdery mildew pathogen encounters not only barley, but also corn or rice, which are not normally infected by the fungus. The project team will compare these host versus nonhost interactions to better understand how cereal crops withstand pathogen attack.
“Whenever a plant encounters a pathogen, a massive reprogramming of the plant’s metabolism occurs. The host plant could be sitting there happily in the sunlight, with its genes working to make proteins required for normal growth. When a pathogen attempts to parasitize the host, whole sets of genes are reprogrammed to do other things; they either help defend the plant or they’re co-opted by the pathogen to suppress host defenses. So you’ve got thousands of genes doing things they normally wouldn’t do,” Wise said.
In temperate regions, the powdery mildew fungus that infects barley can reduce crop yields by as much as 40 percent. Other closely related powdery mildew fungi infect squashes, beans, strawberries, grapes, roses, apple and oak trees. In a major breakthrough in understanding the biology of the powdery mildew fungi, a team in the UK recently sequenced the genome of the one that infects barley. It is one of the largest fungal genomes reported to date.
The sequencing team is led by researcher Pietro Spanu at the Imperial College in London. Wise and Spanu met at a conference in Italy in 2007 and initiated their collaboration at a meeting in Minneapolis the next year. Afterwards, they drove to Ames, sightseeing through the corn fields and brainstorming along the way. Spanu’s group will identify and supply “effector” genes that might be involved in causing powdery mildew disease. Wise and Adam Bogdanove, associate professor of plant pathology, will test the effectors on barley, corn, and rice using a bacterial delivery system. “Instead of taking a whole pathogen and a whole plant, we can take single genes and look at them one at a time,” Wise said.
Spanu’s work is funded by a grant from the Biotechnology and Biological Sciences Research Council, the UK’s leading funding agency for academic research and training in the non-clinical life sciences. “It is often difficult to coordinate projects independently submitted for funding in two different countries. In our case, the timing was perfect and the synergy was easy to recognize,” Wise said.
Wise’s project also will build on an outreach program created by previous plant genome grants at Iowa State. The NSF Research Experience for Teachers, led by Adah Leshem-Ackerman, program manager in the ecology, evolution and organismal biology department, will bring high school science teachers to work in project labs.
“They complete a project and create a poster, but the goal is to take the research methodology they gain and incorporate it into their curriculum,” Wise said. The new NSF funds will be used to train teachers in a classroom module on gene expression and co-segregation analysis. These are essential concepts important in areas from agriculture to human health and will give the students early exposure to approaches and technologies that enable the newest scientific breakthroughs.
During the school year, the students will carry out molecular genetics experiments on a collection of Oregon Wolfe barley plants that exhibit exceptionally diverse and dramatic characteristics.
“A big benefit is that the grant will purchase scientific equipment and supplies teachers can use in the classroom to complete the experiments. This stuff is really cool when they get to do it, but so often they only see it in a book,” Wise said.
In addition to Bogdanove and Leshem-Ackerman, the team of researchers at Iowa State includes Dan Nettleton, statistics, and Julie Dickerson, electrical and computer engineering.