Biological Activity of Actinobacterial Biosurfactants Towards Biofim Formation by Xanthomonas arboricola pv. juglandis Strains

This study evaluated the anti-biofilm activity of the lipopeptide of Streptomyces lavendulae subsp. lavendulae 214 and aminoglycolipid biosurfactant of Streptomyces griseoflavus 2265 strains against biofilm formation by Xanthomonas strains. The biosurfactants of Streptomyces griseoflavus 2265 and Streptomyces lavendulae subsp. lavendulae 214 at a minimal concentration of 40 mg/L, characterized by antibiofilm activity against the development of Xanthomonas arboricola pv. juglandis 2417 strain and its mutant strains. The structure of the isolated biosurfactant was identified using Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR). The mutations in the rpfA gene of Xanthomonas arboricola pv. juglandis 8636 strain and deletions in the rpfGC genetic segment of Xanthomonas arboricola pv. juglandis 8737 strain did not ensure resistance to the effects of antimicrobial agents secreted by actinomycetes strains during the study. The concentration of aminoglycolipid biosurfactant of Streptomyces griseoflavus 2265 strain up to 20 mg/L and lipopeptide biosurfactant of Streptomyces lavendulae subsp. lavendulae 214 strain up to 10 mg/L stimulated cell motility in Xanthomonas arboricola pv. juglandis strains, while the increase in their value was accompanied by its inhibition, which was not affected by mutations in the rpfA gene of Xanthomonas arboricola pv. juglandis 8636 strain and deletions in the rpfGC genetic segment of Xanthomonas arboricola pv. juglandis 8737. These results may provide fundamental information for understanding the antagonistic effect of biological surfactants from soil microorganisms, which are dominated by actinomycetes, on the development and spread of Xanthomonas arboricola pv. juglandis strains of different genotypes on agricultural crops.