Rwandan Scientist Works With MSU Researcher To Battle Plant Disease

A Rwandan scientist is working with Montana State University scientists to understand a disease that is devastating to staple food crops in his country.

Theodore Asiimwe, director of agriculture in Rwanda’s southern agriculture zone and coordinator of biotechnology unit of his country’s agriculture board, is completing a three-month fellowship at MSU that will help him understand Ralstonia solanacearum, the causal agent of potato bacterial wilt as well as wilt in crops that belong to the solanaceae family, such as tomato and eggplant.

Asiimwe is at MSU on a Borlaug Fellowship administered through the U.S. Department of Agriculture. The Borlaug Fellowship promotes agricultural development by supporting scientists from developing countries.

Asiimwe came to MSU in October to work with Barry Jacobsen, MSU professor and Extension specialist in plant pathology. Jacobsen is an expert in potato and sugarbeet diseases, especially the biological control of soil borne pathogens and noxious weeds. Asiimwe is also working with other MSU scientists, including Alice Pilgeram and David Sands.

“Because the pathogen is economically important in my country, I needed to work with someone in the U.S. who had a background with it,” Asiimwe said. “With Ralstonia, you want to get it right from beginning.”

R. solanacearum is a pathogen found worldwide, but is most common in tropical environments. It survives in soil and surface water and infects plants through the roots, multiplies in xylem vessels blocking water transport leading to wilting and death of the plant, Asiimwe said.

Although R. solanacearum is not found in Montana, Jacobsen has studied the pathogen. He said strains do exist that could survive Montana’s winters and could threaten the state’s potato seed industry. One of his previous graduate students, who was from the African country of Mali, wrote her graduate thesis on the races of the bacteria found in her samples of Ralstonia. The results were published and the USDA, which sponsors the Borlaug scholar program, contacted Jacobsen to see if he would be willing to work with Asiimwe.

Jacobsen explains that once the races of the bacteria in the Rwandan samples are identified, scientists can determine the best means to control the disease, including resistant potato varieties, biocontrols and disease-resistant root stocks of tomato and other crops.

While at MSU, Asiimwe is using different techniques such as use of selective media, biochemical characterization, immuno studies, plant-host pathogenicity trials and DNA fingerprinting to understand the soil-borne pathogen.

As part of the program, Jacobsen traveled to Rwanda, which he calls a “stunningly beautiful and progressive country,” to help Asiimwe collect samples that were brought to MSU.

“A lot of what he is doing is DNA work, which is the modern way to identify races,” Jacobsen said. “We can also do confirming work in the plant quarantine center here. We are unique in having that ability.”

In fact, Asiimwe said while he was working at MSU he was surprised to learn the rate at which Ralstonia solanacearum becomes contaminated, making it hard to get pure isolates.

Jacobsen said that when Asiimwe returns to Rwanda Jan. 10, he’ll be able to set up experiments similar to the ones he has been doing at MSU and continue his research. Jacobsen will also return to Rwanda to help Asiimwe implement Ralstonia management strategies there.

While he is at MSU, Asiimwe is also learning about Montana’s potato seed certification program. While Rwanda has a program to produce disease-free potato seed that is similar to Montana’s, Asiimwe has seen how the seed program can be transferred to private certified seed growers.

Asiimwe won distinction among this year’s 34 Borlaug scholars, who hail from developing countries in Asia, South America, Africa and the Middle East, when he was selected to give a few remarks and introduce U.S. Secretary of Agriculture Tom Vilsack at a Borlaug meeting on the sidelines of the 2011 World Food Prize events.

The scholars are in the U.S. on a USDA program honoring Norman E. Borlaug, who won the Nobel Peace Prize in 1970 for his success in developing high-yield wheat varieties and reversing severe food shortages in India and Pakistan in the 1960s. The goal of the program is to help increase scientific knowledge in developing countries through collaborative research that will improve agricultural productivity.

“I have enjoyed being able to work with knowledgeable scientists who offered me great hospitality,” Asiimwe said.