Weeds Associated Bacterial Endophyte Producing Pantocin against Pectobacterium carotovorum subsp. carotovorum

In the present study, bacterial endophytes were obtained from weeds of potato fields. Their antagonistic activity was screened against potato storage pathogen, Pectobacterium carotovorum subsp. carotovorum (Pcc) (JX029052), in the maceration assay. An endophytic strain, PC-2B was isolated from Convolvulus arvensis L. as a dominant weed of potato fields. In vivo application of this strain led to 58.8% reduction in tuber decay. This motile strain that can produce amylase was identified as Pantoea sp. using phenotypic features and 16S rRNA sequencing. Following PC-2B treatment, 56.7% Reduction in Disease Incidence (RDI) was obtained in preventative and 52% in curative challenges under semi-practical storage trails. Anti-Pcc bioactive compounds of Pantoea sp. was extracted and identified based on H NMR and FT-IR techniques. Two peptide antibiotics including Pantocin A and B with inhibitory effect against Pcc were characterized. These results might indicate that the tested Pantoea strain could be a promising candidate to protect potato tubers against soft rot disease caused by Pcc. However, large-scale complementary trials have to be conducted to validate these results before any recommendations.