BACKGROUND: Bacterial shot hole of stone fruits is a seriuos platn disease caused by Xanthomonas arboricola pv. pruni (Xap). Techniques to control the disease are required. In this study, microorganisms with antibacterial microorganisms were isolated to develop as a microbial agent against the bacterial shot hole.
METHODS AND RESULTS: An isolate with the strongest activity among the isolates was identified as Streptomyces avidinii based on 16S rRNA gene sequence analysis and designated Streptomyces sp. J46. J46 showed suppression of bacterial leaf spot with a control value of 90% at 10 times-diluted cell free supernatant. To investigate antibacterial metabolites produced by J46, the supernatant of J46 was extracted with organic solvents, and the extracts were subjected to chromatography works. Antibacterial metabolites were not extractable with organic solvents. Both reversed phase and normal phase techniques were not successful as chromatographic methods because the metabolites were extremely water soluble. The antibacterial metabolites were not volatiles, but were protein compounds based on hydrolysis enzyme treatment.
CONCLUSION: Our study suggests that Streptomyces sp. J46 may be a potential as an microbial agent against bacterial shot hole. Further study to identify the metabolites is required in more detail.