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PRIMARY INVESTIGATOR:
Dr. Richard T. Sayre, Ohio State University, Ohio, United States - US
Improving Cassava for Nutrition, Health, and Sustainable Development
Research ObjectivesProject Progress & Milestones
Collaborators
Project

Poor nutrition is a major global health problem, contributing to half of the nearly 10 million deaths that occur each year in children younger than 5 and much of the death disease and suffering impacting sub-Saharan Africa.  A starchy root crop called cassava is the major source of calories for more than 250 million Africans in this region, but cassava has the lowest protein-to-energy ratio of any staple crop.

A typical diet based on cassava provides less than 30 percent of the minimum daily requirement for protein and only 10-20 percent of the required amounts of iron, zinc, vitamin A, and vitamin E. Moreover, because it carries low levels of a naturally occurring cyanide, cassava can be toxic if is not prepared properly. A promising long-term solution to this problem is to genetically modify crops, like cassava, that grow well in harsh climates so that they have high levels of essential nutrients. 

Dr. Sayre is leading a multidisciplinary team of scientists, brought together as BioCassava Plus, that is working to create nutritious cassava for sub-Saharan Africa.  Team members are screening additional transgenic plants and expect that complimentary genetic strategies currently underway will soon yield plants that achieve their targeted levels of iron, zinc, and protein.

Research Objectives:
Develop a novel cassava germplasm with increased levels of bioavailable zinc, iron, protein, and vitamins A and E
Lower levels of cyanogenic glycosides, which can compromise the health of consumers, especially those who are undernourished
Improve durability after harvest so roots can be stored longer
Increase resistance to viral disease
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Project Progress & Milestones:
Generated transgenic plants that contain targeted levels of vitamins A and E in their storage roots.
Achieved 75 percent of the targeted objective for root protein content and 30-40 percent of targeted objectives for iron and zinc content in initial screens of transgenic roots.
Produced cyanide-free plants that develop full-sized storage roots.
Developed two independent transgenic strategies for producing virus-resistant plants that provide protection against viral infections in the lab and in the greenhouse.
Progressed toward molecular, biochemical, and genetic characterization of post-harvest physiological deterioration (PPD). Investigators have determined that reactive oxygen species (ROS) mediate PPD and that cyanide-dependent inhibition of cytochrome C oxidase activity leads to copious ROS production.  They have determined base-line levels of ROS metabolizing enzyme activity and are generating transgenic plants expressing ROS metabolizing enzymes.
Identified cassava hybrids with reduced PPD phenotypes. These are being biochemically characterized.
Began field trials of transgenic plants with reduced cyanide levels in foods in Puerto Rico. The first transgenic field trials for biofortified and virus resistant cassava are schedule to begin in 2007.
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Collaborators:
Danforth Plant Science Center, Missouri, United States - US
University of Bath, United Kingdom - GB
Centro Internaçional de Agricultura Tropical, Colombia - CO
Zentrum-ETH, Switzerland - CH
Washington State University, Washington, United States - US
University of Puerto Rico, San Juan, Puerto Rico - PR
International Institute Tropical Agriculture, Ibadan, Nigeria - NG
National Root Crop Research Institute, Umudike, Nigeria - NG
Kenyan Agricultural Research Institute, Nairobi, Kenya - KE
Washington University, Missouri, United States - US
Mikocheni Agricultural Research Institute, Dar es Salaam, Tanzania, United Republic of - TZ
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 Project at a Glance

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 Research Map