Biosynthesized silver nanoparticles inhibit Pseudomonas syringae pv. tabaci by directly destroying bacteria and inducing plant resistance in Nicotiana benthamiana

Abstract Silver (Ag)-containing agents or materials are widely used today in plant protection for their antimicrobial activity. In view of the superior inhibitory ability biosynthesized (aldehyde-modified sodium alginate based) silver nanoparticles (AgNPs) against pathogenic fungi our previous research, here we explored antagonistic effect AgNPs on bacteria and underlying mechanism. We selected Pseudomonas syringae pv. tabaci , causal agent tobacco wildfire disease, as target found that 1.2 μg/mL completely inhibited growth P. vitro vivo by partly destroying cell membrane structure pathogen, resulting cytoplasmic leakage. Moreover, Nicotiana benthamiana treated with exhibited a significant upregulation nonexpressor pathogenesis-related genes 1 ( NPR1 ) gene 2 PR2 ), typical markers salicylic acid (SA)-mediated defense system, an increase peroxidase (POD) polyphenol oxidase (PPO) activities well production reactive oxygen species (ROS). Furthermore, treatment increased chlorophyll content dry weight N. . Overall, demonstrated at low concentration have high pathogen causing disease bacterial inducing resistance host plant. These results lay theoretical foundation further application control diseases.