ERIC-PCR-generated genomic fingerprints and their relationship with pathogenic variability of Xanthomonas campestris pv. punicae, the incitant of bacterial blight of pomegranate.

Bacterial blight caused by Xanthomonas campestris pv. punicae (Xcp) has emerged as a potential threat in pomegranate (Punica granatum) cultivation in India. Here, we report the genomic fingerprints and their correlation with virulence pattern of Xcp isolates from Maharashtra and Delhi. The genomic fingerprints of Xcp isolates were generated using enterobacterial repetitive intergenic consensus (ERIC) sequence-based primers, and virulence level was based on their reaction upon infiltration to susceptible pomegranate cultivar. Maharashtra isolate PGM1 showed only 50% similarity with Delhi isolate PGD8 forming a distinct genotype, whereas the Delhi isolates PGD5 and PGD6 form a cluster with Maharashtra isolates PGM2 and PGM4. The isolates PGM2, PGM4, PGD5, and PGD6 showing mean disease score of 7.47 were marked as group A or highly virulent. The moderately virulent or group B isolates PGM3 and PGD7 produced mean disease score of 4.19, whereas less virulent or group C isolates PGD8 and PGM1 gave mean disease intensity of 1.91. A correlation between genotypic groups based on ERIC fingerprints and pathogenicity of the isolates was established. The highly virulent isolates PGM2, PGM4, PGD5, and PGD6 formed a single cluster. A unique 900 bp amplicon present in all highly virulent isolates has been identified that can be used as genetic marker to screen isolates for virulence. The less virulent isolates PGD8 and PGM1 formed single cluster at 50% similarity coefficient. This seems to be the first report to establish a correlation between ERIC-PCR fingerprints and their corresponding virulence pattern of the pomegranate bacterial blight pathogen.