Identification and Genetic Characterization of pv. from Kiwifruit in Sichuan, China.

pv. causes kiwifruit bacterial canker and poses a major threat to the kiwifruit industry. This study aimed to investigate the genetic characteristics of the pv. population from kiwifruit in Sichuan, China. Sixty-seven isolates obtained from diseased plants were characterized using morphological features, multiplex-PCR, and multilocus sequence analysis (MLSA). The isolates exhibited the typical colony morphology of pv. Multiplex PCR amplification identified every isolate as pv. biovar 3. MLSA of the three housekeeping genes , , and , revealed that the reference strains of the five described biovars were clearly distinguished by a combined phylogenetic tree, and all of the tested isolates clustered with the reference strains of pv. biovar 3. Through a phylogenetic tree constructed from a single gene, it was found that gene alone could distinguish biovar 3 from the other biovars. Furthermore, all pv. isolates analyzed by BOX-A1R-based repetitive extragenic palindromic (BOX)-PCR and enterobacterial repetitive intergenic consensus (ERIC)-PCR clustered into four groups. The clustering results of BOX- and ERIC-PCR indicated that group III had the largest number of isolates, accounting for 56.72 and 61.19% of all 67 isolates, respectively, and the two characterization methods were similar and complementary. The results of this study revealed that the genomes of pv. isolates from Sichuan had rich genetic diversity but no obvious correlation was found between clustering and geographical region. This research provides novel methodologies for rapidly detecting kiwifruit bacterial canker pathogen and a molecular differentiation at genetic level of pv. biovar diversity in China.