Biological Characterization and Genomic Analysis of a Novel Phage vB_XanA_L13.2 Targeting <i>Xanthomonas campestris</i> , a Pathogenic Agent in Tomato in Vietnam

Background: The bacterial spot caused by Xanthomonas spp. is one of the most important diseases on tomatoes in Vietnam. The usage of phages is a promising solution for the biocontrol of the disease. Materials and Methods: We isolated a phage infecting Xanthomonas sp. XC263 from tomato leaf samples. Some biological characteristics and the whole genome of phage were analyzed. Results: The latent period and burst size of vB_XanA_L13.2 (L13.2) were ∼40 min and 2.58 ± 0.53 phages per infected cell, respectively. The phage L13.2 (accession no. PQ093899) belonged to the Autographiviridae family and Pradovirus genus. It lysed nine out of nine strains of Xanthomonas spp. Its genome had 41,106 base pairs in length, a G + C content of 59.9%, and 41 open reading frames. The phage had the most sequence similarity to Xanthomonas phage phi Xc10 (NC_047840.1), with an average nucleotide identity of 92.48% across the genome’s query coverage of 75%. Conclusion: The phage likely represented a novel species within an established genus and would be a promising candidate for phage biocontrol of bacterial spot disease of tomatoes.