Isolation, genomic characterization and biocontrol potential of the lytic Pectobacterium phage Pcc_P10 against soft rot of pepper fruits

Abstract

Pectobacterium carotovorum (PBC) is a major plant pathogen responsible for soft rot disease in peppers, and its prevention and control remain highly challenging. In this study, a novel lytic phage targeting Pectobacterium carotovorum subsp. carotovorum (PCC), designated as Pcc_P10, belonging to the Pektosvirus genus within the Autographiviridae order, was isolated and characterized. The dsDNA genome sequence of Pcc_P10 was 39,637 bp with 49.1 % GC content, encoding 46 open reading frames without tRNA genes and virulence factor genes. Pcc_P10 exhibits specific lytic activity lysing only PCC among a panel of tested bacterial species. Compared to previously reported Pectobacterium phages, Pcc_P10 exhibits a uniquely broad pH tolerance (5–11), a shorter latent period with rapid lytic activity, and a compact genome devoid of tRNA and virulence genes, highlighting its robustness, efficiency, and biosafety as a biocontrol agent. In vitro assays revealed that Pcc_P10 significantly inhibits bacterial growth and disrupts biofilm formation, which has strong potential as a biocontrol agent. In vivo application of Pcc_P10 to infected green peppers resulted in a substantial reduction in soft rot symptoms and a concomitant decrease in PCC populations, demonstrating its efficacy as a biocontrol agent under experimental conditions. Given the growing global concerns regarding the environmental impact and sustainability of chemical pesticides, these findings support Pcc_P10 as a promising candidate for the development of sustainable biocontrol strategies against pepper soft rot.