Save the Soybeans!

By Danniel Arriaga

What do five students from Tuskegee University, spending the summer at Iowa State University have in common?

They are George Washington Carver (GWC) interns, working in associate professor of agronomy Madan Bhattacharyya’s lab with post-doc associates Binod Sahu, Prashant Singh and assistant scientist Sivakumar Swaminathan, on solutions to Sudden Death Syndrome (SDS) in soybeans. SDS is a soil-borne fungal disease caused by a Fusarium pathogen that can cost farmers millions of dollars in lost yields.

The research team, from left:  Prashant Singh, Binod Sahu, Joi Davis, Sivakumar Swaminathan, Jamilah Page, Nia Blair, Ellen Tisdale and Vincent Brazelton.

The Tuskegee student interns include Joi Davis, Nia Blair, Ellen Tisdale, Jamilah Page and Vincent Brazelton.

Davis, a recent graduate from Tuskegee University, planted soybeans in a mixture of pre-prepared soil and three isolates of the fungal pathogen, Fusarium virgliforme that causes SDS in soybeans. The plants took three to four weeks to grow. She then screened the preselected 227 soybean plant introduction lines and rated them on a scale of 1 to 7 on how susceptible they were to the disease.

“A lot of my plants didn’t grow, which was unexpected, but when we examined the seeds we noticed that a lot of the seeds were immature and not ready to grow. There were enough plants to continue with scoring,” Davis said.

Blair, an environmental science major, also is part of the SDS project. She is working with a different pathogen that causes root and stem rot in the soybeans and her job is to find out if Fusarium has the same effects on Arabidopsis mutants that were shown to be susceptible the root and stem rot soybean pathogen.

The goal of the project is to identify Arabidopsis genes that make Arabidopsis immune to the soybean SDS pathogen and eventually transfer them to soybeans. Arabidopsis is a weed that has only five chromosomes, making gene mapping easier in the lab.

Blair explained that the Arabidopsis mutant plants are grown, either in the soil or in plastic containers and infected with the fungus after they have fully grown.

“We cut off the leaves of the Arabidopsis mutant plants, infected with the pathogens and then put them under a microscope to see if they’re susceptible. We use a blue dye that shows us any results that the Fusarium has affected the leaves or the seedlings,” said Blair.

Blair also said that there are many things that could go wrong during the process, such as seeds that don’t grow or die during different growing stages.

Joi Davis in the lab.

Davis and Blair came to Iowa State with different interests, Davis is from Nashville and became interested in science because of her pets and moved into animal science; Blair is from Atlanta and became interested in science in high school and is majoring in environmental sciences. Both are working on the same team project to solve SDS.

Page, a sophomore at Tuskegee University, is also mapping an Arabidopsis gene that may confer SDS resistance in transgenic soybean plants.

After following the process of planting the Arabidopsis plants, Page takes off three leaves and places them in a Petri dish with a sample of the spores of the soybean root and stem rot pathogen. If the leaves change color or stay a healthy green and use discoloration to determine if the plant is susceptible or resistant.

“We’re only worried about the ones that cannot fight off the fungus. We’ll go back and look at those original plants and begin the gene mapping to find what makes them resist or not resist the fungus,” Page said.

Tisdale and Brazelton, Tuskegee graduates, are working on the SDS project to map two additional Arabidopsis genes that make Arabidopsis immune to the soybean SDS pathogen. They have started to work with Arabidopsis plants, testing the effects of the soybean root and stem rot pathogen on them.

“First we transplant the seedlings, then we infect the detached leaves with spores of the root and stem rot pathogen for phenotypic analysis. After the analysis we analyzed which ones were susceptible to soybean pathogen and kept them for further analysis. We’ll eventually get to the gene mapping done after extracting some DNA from the susceptible plants,” Tisdale said.

“We are testing on Arabidopsis mutants that are susceptible to the Fusarium fungus to be able to search for genes that will give us resistance to said fungus. Then we’re going to take those genes and apply them to the soybeans,” Brazelton said.

But what truly draws these students to a science-related career? All of them have unique differences and interests, Tisdale has had an interest in how things work scientifically ever since she was young, and a certain orca whale film at the time could’ve sparked this interest. Brazelton originally wanted to continue in a sports related career, but after a college preparation program in high school his interest in science sparked and thrived on. Page has always loved food ever since she was young but her interest in science sparked in sixth grade when her science teacher got creative with miniature volcanoes using hot fudge instead of the traditional baking soda vinegar mix.

They all were surprised about the GWC, expecting to meet different people or working all day benched in a lab. All of them are satisfied and enjoy the diversity that is held within the program and how positive Iowa is overall.

The GWC program brings students from throughout the United States to conduct research and experience life at Iowa State University. The purpose is to bring more diversity to campus and introduce interns to science and Iowa State. For more information, visit http://www.ag.iastate.edu/diversity/gwc/.

Danniel Arriaga, a student at Roosevelt High School in Des Moines, is spending the summer as part of the George Washington Carver Internship and also is part of the program, Science Bound. He is an intern in the College of Agriculture and Life Sciences’ Communications Office, writing news stories about the other GWC interns.