Molecular analysis of the virulence determinants of the phytopathogen Rhodococcus fascians

Most of the virulence determinants of the Gram-positive phytopathogen Rhodococcus fascians reside on a 200-kb linear plasmid, pFiD188. Three major groups of virulence genes can be distinguished on pFiD188. The fas locus contains six genes that encode proteins for cytochrome P450-linked electron transport and an isopentenyl transferase, the actions of which ultimately result in the formation of a hypermodified cytokinin. The art locus is a complex region of 20-kb that encompasses arginine biosynthetic genes and several genes related to polyketide biosynthesis; it probably encodes proteins for the formation of a complex molecule that would enhance susceptibility to infection or sensibility to suboptimal amounts of cytokinins. The third group of virulence genes contains regulatory proteins that are involved in control of the expression of fas and an both on the transcriptional and translational level. Besides these pFiD188-encoded loci one chromosomal virulence locus vie, was characterized. It is possibly involved in the catabolism of a gall specific compound that functions as a specialized carbon and nitrogen source for R. fascians.Most of the virulence determinants of the Gram-positive phytopathogen Rhodococcus fascians reside on a 200-kb linear plasmid, pFiD188. Three major groups of virulence genes can be distinguished on pFiD188. The fas locus contains six genes that encode proteins for cytochrome P450-linked electron transport and an isopentenyl transferase, the actions of which ultimately result in the formation of a hypermodified cytokinin. The art locus is a complex region of 20-kb that encompasses arginine biosynthetic genes and several genes related to polyketide biosynthesis; it probably encodes proteins for the formation of a complex molecule that would enhance susceptibility to infection or sensibility to suboptimal amounts of cytokinins. The third group of virulence genes contains regulatory proteins that are involved in control of the expression of fas and an both on the transcriptional and translational level. Besides these pFiD188-encoded loci one chromosomal virulence locus vie, was characterized. It is possibly involved in the catabolism of a gall specific compound that functions as a specialized carbon and nitrogen source for R. fascians.P