Evaluation of several strategies for controlling canker plant disease caused by Pseudomonas syringae.

Pseudomonas syringae is a gram-negative bacterium that causes a diversity of diseases in numerous plants. Strategies to inhibit P. syringae growth include protective procedures; however, controlling the disease is complicated due to its rapid spread. Several antimicrobial agents can prevent this disease, such as chemical compounds, biological agents, secondary metabolites, nanoparticles, bacteriophages, and antimicrobial peptides (AMPs). The most effective way to control the disease is through chemical control. Using copper compounds and antibiotics is a conventional practice to decrease canker disease symptoms. However, due to environmental pollution caused by chemicals and bactericides and the resistance of different pathovars of P. syringae, other methods for bacterial pathogens control are needed. Biological control, using antagonistic bacteria has shown promising results against P. syringae under in vitro conditions. New studies focus on using secondary metabolites from plants to control plant diseases. Studies have shown that essential oils when preserved from degradation and evaporation by nanoparticles like mesoporous silica, can increase their antibacterial activities. Using nanoparticles, especially silver, is a suitable strategy for controlling P. syringae. However, high concentrations of silver nanoparticles are toxic. Bacteriophages and AMPs are recommended as alternatives to control bacterial infections in agriculture, including P. syringae. Combined treatments of phages and secondary metabolites have shown higher efficacy, potentially overcoming resistance. However, bacteriophages and AMPs are expensive and limited. In the end, using secondary metabolites and nanoparticles at low concentrations presents economic benefits and antibacterial activities without phytotoxic properties.