Soil application of SiNPs suppress pathogen population and improved plant resistance and antioxidant activity for disease management.

The effectiveness of SiO 2 nanoparticles for their potential to control bacterial wilt (BW) disease in tomato plants was studied. Different concentrations of nanoparticles were first evaluated for their in-vitro antibacterial potential against Ralstonia solanacearum , the causal agent of BW disease. The disease suppressive effect of NP was investigated through in-planta experiments in tomato plants. Nanoparticles exhibited maximum toxicity to R. solanacearum at the concentration of 25 µg/ml and showed a 14.2 ± 0.5 mm growth inhibition zone in a lab test. Tomato plants were grown in pathogen-inoculated soil that was amended with NP suspension. The efficacy of NP application was evaluated for their effect on disease suppression, soil pathogen population, and plant growth and defense response. Results showed that NP at 150 ppm significantly reduced the pathogen population in the soil, as indicated by population count through molecular and dilution count analysis. The NP treatment suppresses the disease index and improves plant growth. The activities of plant antioxidant enzymes were increased, and the expression of resistance genes PR1, PR5, PAL , and PDF - 1.2 were enhanced after NP application. Plants grown in NP-treated soil showed improved photosynthesis and reduced oxidative stress as compared to untreated plants under pathogen stress, and the total phenolic and flavonoid content was enhanced significantly. Moreover, DPPH and FRAP content and AsA/DHA and GSH/GSSG ratios were enhanced, followed by NP application, implying that the non-enzymatic antioxidant capacity of the plants was improved. This study reveals the molecular and physiological action mechanism of managing BW in tomato plants. It suggests that SiO 2 nanoparticles could be included in the integrated management of BW disease as one of the effective components. [Display omitted] • SiO 2 nanoparticles exhibited antibacterial activity against ralstonia solanacearum. • Soil treatment with SiO 2 NP suppress pathogen population in soil. • Application of SiO 2 NP enhanced plant growth and resistance. [ABSTRACT FROM AUTHOR]