Functionalized boron nitride nanosheets conjugated with plant micronutrients as seed dressing agents towards control of bacterial wilt disease†

Plant micronutrients can promote growth and resist the invasion of severe bacterial disease pathogens but their low efficiency and toxicity accumulation need to be addressed. A facile strategy of ionic liquid (IL)-assisted boron nitride nanosheet (BNNS) exfoliation and conjugation with various amounts of ammonium dimolybdate (ADM) providing plant micronutrients was proposed. The specific surface area grew by 14.8% via exfoliation and functionalization by BNNS–IL–ADM. The loading content of ADM within BNNS–IL–ADM with different ratios of ADM was 3.18%, 6.25%, and 10.04%. BNNS–IL–ADM aqueous dispersions under neutral condition exhibited a larger absolute magnitude of zeta potential and manifested better colloidal dispersibility. BNNS–IL–ADM acting as a carrier afforded high loading capacity (509.0 mg g⁻¹) of volatile active ingredients, and also achieved long-term release behavior via the nanoconfinement effect fitting best with the Korsmeyer–Peppas model. BNNS–IL–ADM improved the antibacterial efficiency by 92.86% and 92.50% against soil-borne phytopathogenic bacteria Ralstonia solanacearum in comparison with ADM and commercial formulation. The stem diameter as an index against the infection of R. solanacearum in a pot experiment was increased by 48.28% and 10.26% when treated by BNNS–IL–ADM in comparison with water control and ADM treatment. Moreover, BNNS–IL–ADM showed a promoting effect on seed germination and plant growth and represented facilitated fixation of major organic elements within plant tissue. BNNS–IL–ADM also presented excellent adhesion ability and uniform coating as a seed dressing agent. Such platform offers a feasible strategy for control of soil-borne bacterial wilt disease via triggered sustained release of nutrients and active ingredients acting on-demand.