Cassava Bacterial Blight

Cassava Field

Cassava bacterial blight, incited by Xanthomonas axonopodis pv. manihotis (Xam) is a serious threat to cassava plants in several developing countries in both Africa and South America.

This project will first focus on the genome characterization of Xam to sequence, annotate, and characterize the constellation of bacterial effector (virulence) proteins that are present in naturally occurring field isolates of this important bacterial pathogen. The ability to rapidly and inexpensively determine the genome sequence of natural field isolates of Xam will provide novel insights into the evolution of pathogen virulence and the allelic diversity of effector genes that occur in natural populations. This information will be employed to identify new sources of disease resistance in wild populations of cassava plants.

Previous work has demonstrated that the PthB effector is present in all strains of the pathogen and is essential for the pathogen to cause disease. Work in this project will engineer cassava plants to recognize the PthB protein to provide effective and durable disease resistance. Results from the project are expected to provide a durable source of resistance to this very important bacterial pathogen of cassava. In addition, the knowledge generated in this project will greatly benefit cassava researchers in both Africa and Latin America.