Unspecific Effect of N-phenyl-2-naphthylamine on the Activity of the Adenylate Cyclase Signal System of the Bacterial Agent of Clavibacter michiganensis ssp. sepedonicus Potato Ring Rot

Abstract

The effect of N-phenyl-2-naphthylamine (a negative allelopathic compound present in root exudates of pea (Pisum sativum L.)) on the plankton culture titer and biofilm density, as well as on the activity of adenylate cyclase signal system components and virulence factors (endo- and exocellulases and pectinases) in the causative agent of potato Clavibacter michiganensis ssp. sepedonicus ring rot (strain 6889) has been studied. N-phenyl-2-naphthylamine at a concentration of 9 μM was shown to have no effect on the growth of these bacteria, in both plankton culture and biofilms, or on the activity of the above parameters. An inhibitory effect was exhibited by N-phenyl-2-naphthylamine at a concentration of 45 μM. There was a sharp change in the concentration of intra- and extracellular cAMP levels, which was due to modulation of soluble phosphodiesterase and adenylate cyclase activities: the activation of adenylate cyclase was higher than that of phosphodiesterase in the plankton culture, and significant inhibition of adenylate cyclase and activation of phosphodiesterase were observed in biofilms. Furthermore, N-phenyl-2-naphthylamine had no effect on the activity of transmembrane adenylate cyclase in either bacteria phenotype. Under these conditions, the pectinases and cellulases activities did not change in the plankton culture, but they were significantly stimulated in both biofilms and isolated enzyme forms.