Examination of the reported nucleotide sequences containing avirulence genes of Pseudomonas syringae pathovars suggested that avrA, avrB, avrC, avrPphC, avrRpm1, and avrPpiAI are bordered by sequences similar to those of transposable elements of gram-negative bacteria. Repeat sequences and fragments of at least two different insertion sequences elements were identified at the ends of avrA and avrB, implying multiple transposition events for these areas. A DNA region homologous to a bacteriophage sequence was found upstream of avrPto. The linkage of various virulence/a virulence genes of animal- and plant-pathogenic bacteria with transposable elements and bacteriophage sequences, together with the presence of several of these genes on plasmids, supports, the idea of horizontal transfer and frequent exchange of virulence/avirulence genes among bacterial pathogens.
All Science Journal Classification (ASJC) codes
- Agronomy and Crop Science