Research team receives $7.5 million to study cassava

Ohio State University will lead an interdisciplinary team of scientists in a multi-million dollar project to help improve one of the most important food crops in Africa, cassava.

The Bill and Melinda Gates Foundation selected the BioCassava Plus project as a recipient of one of the foundation's "Grand Challenges in Global Health" program grants. Created two years ago, the goal of the $450 million program is to fund innovative solutions to global health problems.

Leading the $7.5 million, 11-institution cassava project is Richard Sayre, a professor of plant cellular and molecular biology at Ohio State . The grant runs for five years.

Cassava (Manihot esculenta) is the primary food source for more than 250 million Africans – about 40 percent of the continent's population, Sayre said. And the plant's starchy root is a substantial portion of the diet of nearly 600 million people worldwide.

Cassava is the fourth-most-important crop in the tropics, and it's relatively easy to grow in drought conditions. Fully grown cassava roots can stay in the ground for up to two years and needs relatively little water to survive. The roots are a key source of carbohydrates for subsistence farmers in Africa .

The researchers will work on developing new types of cassava plants that have increased levels of zinc, iron, protein and vitamins A and E, and that can also withstand post-harvest deterioration.

But there are downsides to cassava – its roots are low in protein and also deficient in several micronutrients, such as iron, zinc and vitamin A. And once the roots are harvested, certain strains of cassava can produce potentially toxic levels of cyanogens – substances that induce poisonous cyanide production.

"In Africa , improperly processed cassava is a major problem," Sayre said. "It's associated with a number of cyanide-related health disorders, particularly among people who are already malnourished."

Sayre's laboratory focuses on ways to decrease or eliminate cyanogens in cassava roots. Through the BioCassava Plus project, he will work with other experts to increase the root's nutritional value, its shelf life once harvested (cassava roots deteriorate in about two days unless they are properly processed after harvesting) and its resistance to geminivirus, a particularly devastating plant virus that can destroy up to 60 percent of a cassava crop.

A cassava plant usually reaches 3 to 4 feet in height, though some plants can grow up to 13 feet tall.

The researchers will work on developing new types of cassava plants that have increased levels of zinc, iron, protein and vitamins A and E, and that can also withstand post-harvest deterioration.

"The Gates Foundation mandated that we provide complete nutrition in a single crop species," Sayre said. "We hope to achieve each individual goal – to reduce cyanide content, reduce deterioration after harvesting and increase virus resistance.

"Eventually, we'd like to bring all of these traits together into one variety of cassava," he said.

Sayre's colleagues include 18 scientists from 10 research institutions including Ohio State: the U.S. Department of Agriculture in St. Louis; the Danforth Plant Science Center in St. Louis; Washington University Medical School, St. Louis; the University of Bath, United Kingdom; the International Center for Tropical Agriculture (CIAT), headquartered in Colombia; the International Institute of Tropical Agriculture (IITA), headquartered in Nigeria; ETH Zurich in Switzerland; Washington State University; and the University of Puerto Rico.

Source : Ohio State University