Defense and inhibition integrated mesoporous nanoselenium delivery system against tomato gray mold†
Botrytis cinerea (B. cinerea) is a necrotic and nutritive pathogenic fungus that causes gray mold in a variety of economic crops. Due to its multiple infestation patterns and its latent infestation, it is difficult to control. However, traditional chemical antifungal agents are not suitable for long-term treatment of gray mold because of their high toxicity and resistance. In this study, we synthesized mesoporous nano-selenium (Se NPs) with high loading efficiency to combine with the antifungal drug thiophanate-methyl (TM), which enhanced TM's water solubility while reducing its dosage. Based on the synthesis and secretion of oxalic acid by B. cinerea after infection, acid-responsive polyacrylic acid (PAA) was used to plug the mesopores of Se NPs, which led to a highly loaded and responsive nano-drug delivery system (TM@Se@PAA NPs) for effective control of drug release. We demonstrated that TM@Se@PAA NPs at low concentration had a rapid and effective antifungal effect against B. cinerea and did not induce drug resistance. Based on the excellent resistance to B. cinerea in vitro, we designed three in vivo delivery models. The results showed that TM@Se@PAA NPs could effectively prevent and inhibit the growth of B. cinerea, and multiple applications did not produce significant toxic side effects on plants. In particular, TM@Se@PAA NPs could improve the photosynthetic efficiency of plants and promote plant growth to some extent. The results of this study indicated that TM@Se@PAA NPs are promising for the prevention and inhibition of B. cinerea and other destructive fungal diseases.