‘Candidatus Phytoplasma cynodontis’ is widespread in bermudagrass and has only been found in monocotyledonous plants. Molecular studies carried out on strains collected in Italy, Serbia, and Albania enabled verification of molecular variability in the 16S ribosomal RNA (rRNA) gene. Based on restriction fragment length polymorphism and sequence analyses, the strains from Serbia were clearly differentiated from all others and assigned to a new ribosomal DNA (rDNA) subgroup designated as 16SrXIV-C. A system for amplification of fragments containing the ‘Ca. P. cynodontis’ groEL gene was developed to enable study of its variability in related strains belonging to different 16SrXIV subgroups. Despite the fact that the groEL gene exhibited a greater sequence variation than 16S rRNA, the phylogenetic tree based on groEL gene sequence analysis was highly congruent with the 16S rDNA-based tree. The groEL gene analyses supported differentiation of the Serbian strains and definition of the new subgroup 16SrXIV-C. Phylogenetic analyses of both genes confirmed distinct phylogenetic lineages for strains belonging to 16SrXIV subgroups. Furthermore, groEL is the only nonribosomal marker developed for characterization of ‘Ca. P. cynodontis’ thus far, and its application in molecular surveys should provide better insight into the relationships among these phytoplasmas and correlation between strain differentiation and their geographical distribution.

Biological activities of Sorbus aucuparia L. leaves extract were tested in our study. This study aimed to investigate the activity of Cydonia oblonga Mill. peels and leaf ethanolic extracts on biofilm formation of different microbial strains, including pathogenic bacteria and food poisoning strains. It was shown that both of the investigated extracts inhibited biofilm formation in a dose dependent manner with sub-minimal inhibitory concentrations. The percentage of biofilm formation inhibition varied for each bacterial strain and was in the range of 10-100%, for both of the tested extracts. The ability of extracts to inhibit already formed biofilms presented as minimal concentration necessary to disrupt biofilms and concentrations was in the range of 10-100 µg/mL for the leaf extract and 5-75 µg/mL for the peel extract. The investigated extracts showed a promising antimicrobial effect comparable to, or even higher than the used reference compounds, which make these plant parts attractive for pharmaceutical and food industry.

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