Antimicrobial in vitro and in vivo potential of five lichen species on Fusarium oxysporum and Ralstonia solanacearum, agents of potato rots

Using of lichens antimicrobial potential can be one of the safe, green, environment friendly methods for plant diseases management. In this study, antimicrobial activity of acetone, methanol, chloroform extracts of Ramalina capitaat, Xanthoparmelia stenophylla, Umbilicaria cylindrical, Rhizoplaca crysoleuca and Anamylopsora pulcherrima collected from Meshgin shahr and Jolfa mountains were evaluated against two potato rot agents vic. Fusarium oxysporum and Ralstonia solanacearum in laboratory using disc diffusion and minimum inhibitory and bactericide concentration methods and simulated storage conditions. Dimethyl sulfoxide solvent on paper disc was used as negative control. Positive controls were considered as %0.2 benomyl and gentamicin antibiogram discs for fungus and bacterium, respectively. There were no effect of lichens extract on above-mentioned fungus. Chlorophorm extract of R. capitata had remarkable antibacterial activity on R. solanacearum. Extracts of R. crysoleuca and R. capitata were more bacteriostatic and bactericide than others against the bacterium. The study with selected extracts in storage condition showed preventive effect of 80% of extracts on bacterium. The most protective effect was observed in methanol extract of R. chrysoleuca. Therefore, the lichen extracts would be promising biological product as a potential replacement instead of chemicals.