Genetic Divergence and Population Structure of Xanthomonas albilineans Strains Infecting Saccharum spp. Hybrid and Saccharum officinarum

Leaf scald caused by Xanthomonas albilineans (Xa) is a major bacterial disease in sugarcane that represents threat to the global sugar industry. Little known about population structure and genetic evolution of this pathogen. In study, 39 Xa strains were collected from 6 provinces China. Of these strains, 15 24 isolated Saccharum spp. hybrid S. officinarum plants, respectively. Based on multilocus sequence analysis (MLSA), with five housekeeping genes, clustered into two distinct phylogenetic groups (I II). Group I included 26 2 host provinces, while II consisted 13 plants Zhejiang province. Among nucleotide identities 5 genes were: ABC (99.6–100%), gyrB (99.3–100%), rpoD (98.4–100%), atpD (97.0–100%), glnA (97.6–100%). These six (A–F), based rep-PCR fingerprinting, using primers for ERIC2, BOX A1R, (GTG)5. UPGMA PCoA analyses revealed group A had most (24), followed C 11 there was 1 strain each B D–F. Neutral tests showed trend toward expansion. Selection pressure purification selection concatenated all tested strains. Significant differentiation infrequent gene flow found between populations hosted hybrids officinarum. Altogether, results provide evidence obvious divergence structures among