Star polymer soil delivery nanoplatform for applying biological agents in the field to control plant rhizosphere diseases

As the main cause of destructive plant diseases, pathogenic oomycete in plant rhizosphere brings about enormous losses to agricultural production. Although chemical pesticides are still one of the most important prevention and control methods for phytopathogens, the usage of chemical pesticides was limited by the 3R (resistance, residue, and rampant) problem. In the early stage of our research, analysis and comparison of the metabolome of resistance to Phytophthora nicotianae and common strain suggested that naringenin might be a highly efficient potential biogenic antimicrobial agent to prevent and control soil rhizosphere diseases. Unfortunately, the bioactivity and absorption capacity of active ingredients in the environment made it unsuitable for field application; thus, for efficient field application of naringenin, the 24 nm-sized naringenin-loaded nano-star-shaped polymerized (NSPs) were prepared with good loading efficiency 37.3% for naringenin. The soil mobility test indicated that NSPs could effectively reduce the adsorption of active ingredients and enhance the mobility of active ingredients in soil. The bacteriostatic test proved that these NSPs had better antimicrobial activity than the naringenin used alone and could efficiently induce the expression of plant resistance phenylpropanoid compounds. Finally, pot and field experiments showed improved control efficiency of NSPs 41% loaded with naringenin. Transcriptome analysis found that a large number of energy-related genes were downregulated in NSPs nematodes, suggesting that disturbed energy-related genes might lead to the disturbance of energy synthesis and metabolism. Naringenin-loaded nano-carriers were used to prevent and control plant disease-causing pathogens in the rhizosphere, which is of great significance to improve the prevention and control effect and reduce the environmental load of these anti-pathogenic agents.