Rapid progress in the field of plant structural and functional genomics makes the prospect of discovering natural genes for resistance to viruses, bacteria, and insect pests increasingly likely. Transfer of these genes between and across plant families by genetic transformation holds great potential for crop improvement and promises to be a major future activity within agricultural biotechnology. ILTAB’s involvement in the successful transfer of the bacterial resistance gene Xa21 from wild to cultivated rice is an early example of such a strategy. ILTAB will be at the forefront of such activities with respect to major tropical food crops such as cassava and plantain.

Developing countries possess the vast majority of the world’s plant biodiversity. The natural diversity of tropical plant genomes could be utilized through the discovery of genes to control tropical pathogens and address other limiting factors in tropical agriculture. Programs directed at identifying and cloning such genes or gene families will have immediate application within ILTAB’s research projects and could have potential commercial application within temperate crop species.

At this time, several resistance genes have been cloned, and they share a number of common characteristics. In addition to their practical application, such genes will provide new opportunities for studying host-pathogen interactions at the molecular level.

Objectives:

• to clone resistance genes for major tropical crop diseases such as Sigatoka, cassava mosaic disease, and cassava bacterial blight diseases
• to study the molecular functions of these genes
• to transfer natural resistance genes to tropical crops like cassava and plantain

Status of the project:

We are working on the development of several projects through collaboration in LDCs:

• Sigatoka resistance in wild diploid bananas
• Geminivirus resistance in wild peppers
• Virus and bacterial resistance in cassava

Immediate tasks required:

Construction of BAC library, gene mapping, and gene isolation.

Collaborators:

• INIBAP and CATIE for banana
• Cinvestav and CIICA in Mexico for pepper
• EMBRAPA and CIAT for cassava

Basic scientific interests:

Understand how resistance genes function at the molecular level.

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