BACTERIAL LEAF-BLIGHT OF RICE - NEW INSIGHTS FROM MOLECULAR-GENETICS

The bacterial pathogen Xanthomonas oryzae pathovar oryzae causes a ser ious disease of rice. Over the last decade, considerable progress has been made in the application of the techniques of genetics and molecul ar biology towards understanding the rice-Xanthomonas interaction. Sev eral interesting pathogen genes for virulence and avirulence have been cloned. DNA fingerprinting studies have provided information about th e genetic diversity within populations of this pathogen. A number of r ice genes that confer resistance against X. oryzae pv. oryzae have bee n tagged with closely linked molecular markers. Rice breeding lines wi th multiple resistance genes have been obtained by using these markers . The sequence of one of these genes suggests that it encodes a putati ve receptor kinase which recognizes an elicitor produced by the pathog en and initiates a signal transduction cascade. that ultimately result s in resistance.