ABSTRACT
Bacterial pathogens cause destructive diseases and remain a formidable limiting factor to crop production all over the world. The ability of bacterial pathogens to multiply and reach huge population levels rapidly under favorable conditions, poses problems in containing the incidence and spread of bacterial diseases in various crops cultivated in different ecosystems. Bacterial wilt diseases caused by Ralstonia solanacearum affect many economically important crops like tomato, potato, pepper and banana accounting for enormous losses, since the infected plants are ultimately killed. Generally, visible symptoms of infection appear only after the pathogen has become well established in the vascular system and at this stage, it is very difficult to save infected plants. It may be possible to protect the neighboring uninfected plants by applying preventive measures. Soft rot diseases caused by Pectobacterium (syn. Erwinia) affect several vegetable crops, inducing extensive rotting of the plant tissues, making the produce unmarketable. These bacterial diseases have worldwide distribution, resulting in variable losses, depending on the susceptibility/resistance levels of crop cultivar, the virulence of pathogen strain and the existing environmental conditions. It is essential to have knowledge on various aspects of the biology of bacterial pathogens such as biological characteristics, host-bacterial pathogen interactions, process of infection and molecular biology of disease development (pathogenesis) for the development of effective disease management systems.
