Bioactive Metabolites and Anti-Phytopathogenic Potential of Erica verticillata: A Targeted Leaf Extract Study

Plant pathogenic microorganisms pose significant threats to agriculture, necessitating the exploration of natural alternatives to conventional pesticides. This study aimed to investigate the antimicrobial potential of methanolic extracts from Erica verticillata against various plant pathogenic bacteria and fungi. The antibacterial assays revealed substantial activity of the extract, indicating that Pectobacterium atrosepticum and Streptomyces scabiei exhibited sensitivity at a concentration of 300 µg/ mL. At the same time, Ralstonia solanacearum and Pectobacterium carotovorum displayed sensitivity at a concentration of 500 µg/ mL. Antifungal evaluations revealed potent inhibition against Fusarium oxysporum, Botrytis cinerea, and Rhizoctonia solani. The extract strongly inhibited B. cinerea (78.2 % at 5000 µg/ mL) outperforming copper hydroxide (58.7 %). Significant in vitro inhibition was also observed against R. solani and F. oxysporum, often exceeding the positive control. Phytochemical analysis using HPLC revealed that the predominant phenolic components were gallic acid, caffeic acid, and syringic acid, with concentrations of 2620.3, 606.5, and 580.9 µg/ g, respectively. The principal flavonoid was quercetin at a concentration of 169.4 µg/ g. Hexadecanoic acid and phorbol were the most prevalent secondary metabolites identified in the GC-MS analysis, comprising 26.4 % and 16.4 %, respectively. These findings highlight the rich phytochemical profile of E. verticillata and underscore its potential as a source of natural antimicrobial agents for managing plant diseases, including those caused by antibiotic-resistant pathogens.