Insights on plasmids and their role in evolution of Xanthomonas

Xanthomonas, comprising twenty-seven Gram-negative bacterial species, poses a significant threat to numerous plant species by causing severe diseases. Plasmids which are common components of phytopathogenic bacteria, play a crucial role in disease development as well as in the diverse evolution of their hosts. Plasmids carry virulence factors along with ecological variability which contributes in the pathogen's adaptation, through many traits acquired through horizontal transfer from other bacteria, thereby highlighting their vital role in rapid evolution. These plasmids are equipped with self-transmissible features and genes which are capable to encode a specific secretion system (Type IV). The "mobilome" of plant pathogenic bacterial plasmids encompasses particular insertion sequences and special transposable elements, which facilitate the intra and inter- transfer of genomic sequences. This review seeks to provide a comprehensive overview of the distribution, classification, transfer of plasmids, bacterial evolution, and the roles of plasmids in pathogenicity, antibiotic resistance, heavy metal resistance, and evolution associated with Xanthomonas.