Fabrication of polydopamine reduced CuO nanoparticle-alginate composite nanogels for management of Pseudomonas synringae pv. tabaci in tobacco.

Background: The wildfire disease on tobacco can seriously hinder plants. Meanwhile, its pathogen, Pseudomonas syringae, can also infect over 200 plants and threat agriculture production. However, the disease usually occurs after summer rains which washes away most copper (Cu)-based bactericides, allowing the disease to invade. Therefore, we fabricate a new nanogel with high disease control and anti-erosion ability and study the effects of the reductant on the performance of the copper oxide nanoparticle (CuONP) composite nanogel.

Results: Polydopamine (PDA) is a polycation for both in situ reduction of CuONP in alginate nanogels and for adjusting the copper ion (Cu ) releasing rate in this work. The composite nanogel fabricated by PDA (PDA-CuONP@ALGNP@CTAC) had a higher Cu releasing rate, damaging the pathogen membrane more efficiently, allowing for better disease control and plant growth promotion when compared to sodium borohydride (SBH)-fabricated nanogel (SBH-CuONP@ALGNP@CTAC) or the commercial bactericide, thiodiazole copper. The PDA-CuONP@ALGNP@CTAC had a high anti-erosion ability and could remain adhered to the leaf surface even after five rain event simulations.

Conclusion: The addition of polycations (like PDA) into CuONP composite nanogel could increase the Cu releasing rate, resulting in improved disease management when compared to SBH-CuONP@ALGNP@CTAC or thiodiazole copper. The PDA containing gel had an improved anti-erosion ability and water resistance. This new composite nanogel has a high potential for wildfire disease control, improving agricultural production. © 2022 Society of Chemical Industry.