Phylogenomic Insights into Diversity and Evolution of Nonpathogenic Xanthomonas Strains Associated with Citrus

Abstract

Xanthomonas citri is one of the top phytopathogenic bacteria and is the causal agent of citrus canker. Interestingly, Xanthomonas is also reported to be associated with healthy citrus plants. The advent of the genomic era enabled us to carry out a detailed evolutionary study of a Xanthomonas community associated with citrus and other plants. Our genome-based investigations have revealed hidden and extreme interstrain diversity of nonpathogenic Xanthomonas strains from citrus plants, warranting further large-scale studies. This indicates an unexplored world of Xanthomonas from healthy citrus plant species that may be coevolving as a species complex with the host, unlike the variant pathogenic species. The knowledge and genomic resources will be valuable in evolutionary studies exploring its hidden potential and management of pathogenic species.