Silica nanoparticles enhance plant disease resistance by modulating the endophyte community structure in tomato (Solanum lycopersicum L.) roots†

Nanoparticles have attracted widespread attention for their positive role in suppressing plant diseases. In the present work, the impact of solid silica nanoparticles (SNPs) on the bacterial community of tomato root endophytes under Ralstonia solanacearum (Rs) infection was investigated. Tomato infection by Rs led to a 17.78% reduction in shoot fresh weight and a 66.44% reduction in root fresh weight. Repeated three soil applications of 650 mg L⁻¹ SNPs significantly suppressed bacterial wilt, with a 40.27–48.96% reduction in the disease index. SNPs also significantly increased the shoot fresh and dry weight by 17.43% and 17.13%, respectively. In the roots, SNPs altered the structure and increased the diversity of the endophytic bacterial community in infected plants. Notably, Mitsuaria, Sphingobium, Streptococcus, and Rhizobium were enriched with SNPs–Rs treatment; these are identified as beneficial bacteria that facilitate plant resistance to pathogens. Additionally, SNPs' application significantly increased the concentrations of N (27.01%), K (8.34%), and Si (11.01%) in roots under Rs infection. A correlation analysis indicated that nutrient concentration in roots was positively correlated with bacterial community diversity. These data show that SNPs can enhance plant resistance to disease by regulating the structure and diversity of root endophyte communities and improving plant nutrition. Our findings have important implications for the application of nanoparticles in sustainable nano-enabled agriculture.