PATHOLOGICAL AND MOLECULAR CHARACTERIZATION OF XANTHOMONAS-CAMPESTRISSTRAINS CAUSING DISEASES OF CASSAVA (MANIHOT-ESCULENTA)

Fifty-one strains representing Xanthomonas campestris pv. manihotis an d cassavae and different pathovars occurring on plants of the family E uphorbiaceae were characterized by ribotyping with a 16S+23S rRNA prob e of Escherichia coli and by restriction fragment length polymorphism analysis with a plasmid probe from X. campestris pv. manihotis. Pathog enicity tests were performed on cassava (Manihot esculenta). Histologi cal comparative studies were conducted on strains of two pathovars of X. campestris (vascular and mesophyllic) that attack cassava. Our resu lts indicated that X. campestris pv. manihotis and cassavae have diffe rent modes of action in the host and supplemented the taxonomic data o n restriction fragment length polymorphism that clearly separate the t wo pathovars. The plasmid probe could detect multiple restriction frag ment length polymorphisms among strains of the pathovar studied, Ribot yping provides a useful tool for rapid identification of X campestris pathovars on cassava.