<i>Lantana camara</i> L.: a potential biocontrol agent against phytoplasma infection in chili plants

Phytoplasma, a phytopathogenic mollicute, poses a major threat to global agriculture with no effective control strategies currently available. <i>Lantana camara</i> L., an invasive weed, contains bioactive compounds with promising antimicrobial potential. This study investigates its potential, by utilizing the bioactive potential of green unripe berry extract from <i>Lantana camara</i> L., to mitigate phytoplasma infections in chili plants (<i>Capsicum annuum</i>). Phytoplasma infection in symptomatic chili plants was confirmed by nested PCR. Treatment with optimized <i>L. camara</i> extract led to significant recovery from little leaf disease. GC-MS analysis of <i>Lantana camara</i> L. green unripe berries identified six bioactive compounds with potential phytoplasma-inhibitory and antibacterial properties. To further explore their therapeutic potential, molecular docking studies were performed against the target protein SAP05 effector complexed with AtRpn10 (PDB ID: 8JTL) which is a known effector protein associated with phytoplasma pathogenicity. Among the docked compounds, Carsalam showed the strongest binding affinity (–7.2 kcal/mol) by interacting with Lys56 (C) residue. Other compounds like 5-(4-Chlorobenzyl)-1H-tetrazole and Cyclohexylmethylphosphonic acid also exhibited strong binding and targeted critical residues involved in protein function. These findings suggest <i>L. camara</i> has the potential to inhibit phytoplasma, marking a preliminary step toward sustainable phytoplasma management and an alternative to chemical treatments. The present study proposes an innovative approach that uses the green unripe berry extract of <i>Lantana camara</i> L. to treat phytoplasma-induced symptoms in chili plants. While <i>Lantana camara</i> L. is well-known for its invasive behavior, this study reveals its distinctive application in biological control of phytoplasma, providing an eco-friendly alternative to typical synthetic antibiotics. GC-MS analysis revealed the presence of six bioactive chemicals highlighting the botanical extract’s potential as biocontrol agent with antibacterial activities. Importantly, molecular docking studies further validated the phytoplasma-inhibitory potential of the GC-MS identified compounds, particularly against the 8JTL protein, a structural representation of the SAP05 effector protein from Onion Yellows (OY) phytoplasma bound to the <i>Arabidopsis thaliana</i> Rpn10 protein. The docking results showed that five ligands, especially Carsalam, exhibited strong binding affinities with key amino acid residues of the 8JTL protein, suggesting possible interference with phytoplasma virulence mechanisms. This makes a significant contribution to sustainable agriculture by reducing the dependence on chemical treatments, opening avenues for developing targeted botanical formulations for biological control of phytoplasma and also promotes ecological balance by repurposing an invasive plant for agricultural benefits. Patent: 202411073027. The present invention in particular relates to a method of preparing a spray with botanical extract from <i>Lantana camara</i> L. unripe green berries that actively suppresses phytoplasma symptoms in symptomatic Chili plants.