Clavibacter michiganensis, a group of gram-positive phytopathogenic bacteria

The actinomycete genus Clavibacter contains several important pathogens infecting plants of agricultural importance. These Gram-positive bacteria display differences in their mechanism of pathogenicity as compared to the proteobacteria. They are vascular pathogens causing systemic infections after entering the hosts through wounds. The occurence of symptomless latent infections and the invasion of the seeds by the bacteria are widespread. On the molecular level distinct pathogenic mechanisms seem to exist, as no resistant host plants are known and a type III secretion system or avirulence genes have not been identified so far. In this chapter an outline of the biology and the current knowledge on the molecular basis of disease induction by Clavibacter is presented