Adaptation of FTA card aids world food crops
Photo from whatman.com
The secret’s in the coating The deceptively simple power of an FTA card lies within its special matrix coating. Embedded chemicals disrupt cells, denature proteins and protect nucleic acids (DNA and RNA) from destruction by enzymes, oxidation or ultraviolet light. This process inactivates bacteria or viruses that may be present in the plant sample.
Under an electron microscope, the matrix appears as a sticky spider web that entraps strands of DNA/RNA – safely conveying them to Rayapati’s lab for analysis.
“When I am in the jungle in Africa, it is easy to stick a card in my bag and bring it back to my lab in Prosser without losing the integrity of the nucleic acids,” Rayapati said. “We analyze the samples and the results are sent back to the host country.”
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Humble yet ingenious. A scrap of heavy gauge paper, the size of a postcard, is being used by WSU scientists to help eradicate crop diseases in developing countries around the world.
In an age of globalization, developing nations often benefit from the input of new ideas. But, in some cases, changes to traditional agricultural practices have unleashed new problems for subsistence farmers in Africa, Asia and South America. Unforeseen consequences, such as rampant spread of viral diseases, can be deadly – decimating crops and wreaking economic ruin for families and communities already living on the edge.
“Many farmers are unaware of plant viruses, knowing only that plants are dying or that fruits appear irregular. This makes management of viral diseases in plants especially difficult,” said WSU plant virologist Naidu Rayapati.
Diagnosing those diseases is also a problem, particularly for countries with scarce resources and poor infrastructure. In addition, U.S. scientists hoping to bring samples back to their laboratories for testing face stiff federal regulations prohibiting the transport of live plant material into the country.
But Rayapati, an assistant professor in the Department of Plant Pathology – based at WSU’s Irrigated Agriculture Research and Extension Center in Prosser – puts his faith in creative thinking and bringing people together to solve common problems.
FTA Classic Cards offer simple remedy
Rayapati discovered that many medical scientists were using FTA Classic Card technology to test for HIV/AIDS, malaria and other diseases in developing countries. Blood samples are collected from villages and stored on small cards, then easily transported to a central location for testing. Even better, the cards are stable at room temperature and can be shipped in the mail.
Rayapati thought a similar process could be used to diagnose plant diseases. The leaves or other tissues of an infected plant could be rubbed on the card, capturing sap instead of blood.
“With the cards, only harmless nucleic acids (DNA or RNA) are brought into the country,” he said. “Any pathogens that may be present – bacterial, viral or parasitic – are inactivated and no longer infectious.”
Backed with funding by the U.S. Agency for International Development (USAID), Rayapati and his team members in the Integrated Pest Management-Collaborative Research Support Program (IPM-CRSP) began using the FTA cards for plant diagnostics in 2005.
Saving yard-long beans
Five years later, Rayapati boasts a string of success stories as well as international awards for his work with the FTA cards. Although the technology has been used on a limited basis, he believes there is much broader potential for this type of program. In fact, his lab has begun using the cards to detect not only crop viruses, but also the insect vectors that spread the diseases.
In 2008, for instance, farmers in Java lost more than 80 percent of their crop of yard-long beans – a popular legume extensively cultivated in Indonesia – to an unknown viral epidemic. Using FTA cards, Rayapati and his colleagues were able to identify the virus as a strain of the bean common mosaic virus, which has been documented in many countries, including the U.S.
It was discovered that Indonesian farmers had been using yard-long bean seed imported from China, Taiwan and Thailand. Rayapati speculates that the virus was introduced through the seed and then spread throughout the region by aphids.
“By providing an accurate diagnosis on a plant virus problem, scientists can use that knowledge to educate farmers about contaminated seed and help them stop using it,” he said. “We also provide information to the seed companies to ensure they provide quality seed to farmers – and help stop the spread of viruses to other countries.”
By 2009, Java farmers were able to grow enough healthy yard-long beans to overcome their previous losses.
“Now it is easy for them to manage any problems,” Rayapati said with a smile. “The beauty is that people who are not familiar with the FTA card technology can use it, as it’s so simple; we just send the card to them with instructions and they send it back for analysis.”
Collaboration is key
Nevertheless, it is all but impossible for a handful of field workers to prevail against the poverty and hunger caused by viral crop diseases. Rayapati stressed that in Africa, for example, more than 200 million people suffer from malnutrition, and vegetables are often the only source of essential vitamins and nutrients for those unable to afford meat.
As a result, he and his team are urging scientists in developing countries to find innovative ways to conduct research and work collaboratively.
“We encourage them to form partnerships among fellow institutions and to take advantage of the benefits offered by international agencies supporting ‘science for development’ programs within Africa, such as USAID,” he said.
“Partnerships are critical to the fight against the spread of viral diseases, and no single institution can do it alone,” he said. “Some of the major challenges faced by scientists in sub-Saharan Africa are the prohibitive costs of equipment and facilities such as laboratories. To overcome this challenge, scientists must think outside the box.”
WSU already is playing a leading role in partnering with international agriculture programs. Scientists from India, Indonesia and Africa often send – or personally deliver – plant samples on FTA cards to Rayapati’s laboratory in order to take advantage of his state-of-the-art diagnostic equipment.
Genetic mapping
In the laboratories, graduate student Sudarsana Poojari and collaborator Pat Okubara, a USDA/Agricultural Research Center geneticist, use techniques such as real-time polymerase chain reaction (PCR) to detect viral pathogens on the cards. With PCR, the DNA or RNA of viruses, bacteria or fungi can be sequenced and the genetic codes mapped.
In one case, graduate student Olufemi Alabi used the FTA cards to successfully identify two new strains of virus infecting soybeans in Nigeria. The team also has developed techniques to better identify disease in wine grapes – a vital industry for the Washington state economy.
“The downstream implications for this technology are huge,” Rayapati said. “The FTA card project not only impacts plant breeding programs, international disease control efforts and U.S. biosecurity issues, but we also are creating databases to track disease outbreaks across the globe.”
Incorporating these international dimensions into WSU’s academic programs is a priority for Rayapati.
“We want to ensure that domestic students are competent to succeed in the international workforce and to strengthen our nation’s continuing ability to compete globally,” he said.
