Synergistic Interaction of Silicon Dioxide Nanoparticles (SiO2NPs) and Pseudomonas fluorescens to Combat Meloidogyne incognita Infestation: Enhancing Growth, Biochemical and Antioxidant Activities in Trachyspermum ammi (L.)

The majority of the crops under cultivation are being negatively impacted by root-knot nematodes (RKN), especially Meloidogyne spp. Chemical pesticides are typically employed to control this nematode, which has negative effects on the environment, people, animals, and soil health. This study investigates the potential of silicond dioxide nanopartiles (SiO2NPs) and Pseudomonas fluorescens to improve biocontrol effectiveness against M. incognita in ajwain plants which causes significant yield losses. In this study we examined the different concentration of silicon dioxide nanoparticles (SiO2NPs) and P. fluorescens singly and concomitantly on various parameters related to mortality of nematode, growth, attributes, photosynthetic pigments, nutrient content, antioxidant enzymes and histological examination of transverse section of roots of ajwain plant infected with the M. incognita. The SiO2NPs used in this study were found to be amorphous and polydisperse, with sizes ranging from 10 to 20 nm, as confirmed by scanning and transmission electron microscopy. The results demonstrated a significant enhancement in the plant growth-promoting properties of P. fluorescens when exposed to various concentrations of SiO2NPs under in vitro condition. Additionally, the combined treatment of SiO2NPs and P. fluorescens significantly increased the mortality of second-stage juveniles (J2). The greenhouse conditions demonstrated that treating M. incognita infected plants in combination of SiO2NPs and P. fluorescens resulted in a significant increase (p <= 0.05) in plant growth and physiological traits, nutrients content, and the activity of antioxidant defense enzymes. This combined application of SiO2NPs and P. fluorescens significantly decreased nematode parameters and the final population of nematodes in the soil. Furthermore, the roots treated with the highest dose of P. fluorescens and SiO2NPs exhibited less deformation in their transverse sections. Combination of SiO2NPs and P. fluorescens can be used as a sustainable environmentally beneficial method to manage plant disease of nematode infected plant.