Multifunctional metal-organic framework with pH-response for co-delivery of prochloraz and siRNA to synergistic control pathogenic fungi

We first report a pH-responsive multifunctional nano pesticide-fertilizer complex based on zeolitic imidazolate framework-8 (ZIF-8) and RNA interference (RNAi) technology for synergistic control of wilt disease caused by Rhizoctonia solani, and promotion of crop growth. Chemical pesticide prochloraz (Pro), biological pesticide small interfering RNA (siRNA), and a plant growth regulator diethyl aminoethyl hexanoate (DA-6) were loaded in Pro/DA-6 @ZIF-8 @siRNA nanoparticles (Nps). The Nps had a rhombic orthododecahedron structure and a hydrated particle size of 841.7 ± 12.8 nm. SiRNA has good stability due to the protection of the nanocarrier as well as an excellent controlled-release behavior under acidic conditions due to the degradation of coordination bonds. The Nps can be adsorbed and transmitted via pathogenic mycelium to enhance the efficacy of non-invasive pesticides. Compared to Pro technical, siRNA and Pro co-delivered by ZIF-8 had a synergistic inhibitory effect on pathogenic fungi. Due to the slow-release of DA-6 and the supply of trace elements, the Nps significantly promoted rice seedling growth by regulation of key metabolic enzymes, and the nutritional function of Nps as a zinc ion fertilizer was demonstrated. Biological studies further verified that nano-carrier had good biosafety and reduced environmental risks. Therefore, this novel nano pesticide-fertilizer complex has potential applications for the effective management of plant disease to enhance environmental safety.