North Florida Research and Education Center, University of Florida, Gainesville, FL, U.S.A.
Department of Plant Pathology, University of Florida, Gainesville, FL, U.S.A.
Plant Dis. 2024 Nov;108(11):3234-3242. doi: 10.1094/PDIS-09-23-1776-RE. Epub 2024 Oct 28.
Bacterial spot of tomato (BST), predominantly caused by () in Florida, is one of the most devastating diseases in hot, humid environments. Bacterial resistance to copper-based bactericides and antibiotics makes disease management extremely challenging. This necessitates alternative new solutions to manage the disease. In this study, we used two novel hybrid copper and magnesium nanomaterials, noted as magnesium double-coated (Mg-Db) and magnesium-copper (Mg-Cu), to manage BST. In in vitro experiments, no viable cells were recovered following 4 h of exposure to 500 μg/ml of both Mg-Db and Mg-Cu, while 100 and 200 μg/ml required 24 h of exposure for complete inhibition. In a viability assay using the live/dead cell straining method and epifluorescence microscopy, copper-tolerant cells were killed within 4 h by both Mg-Cu and Mg-Db nanomaterials at 500 μg/ml but not by copper hydroxide (Kocide 3000). In the greenhouse, Mg-Db and Mg-Cu at 100 to 500 μg/ml significantly reduced BST severity compared with micron-sized commercial copper bactericide Kocide 3000 and the growers' standard (copper hydroxide + mancozeb) ( < 0.05). In field studies, Mg-Db and Mg-Cu nanomaterials significantly reduced disease severity in two out four field trials. Mg-Db at 500 μg/ml reduced BST severity by 34% compared with the nontreated control without affecting yield in fall, 2020. The use of hybrid nanomaterials at the highest concentrations (500 μg/ml) evaluated in the field experiments can reduce copper use by 90% compared with the growers' standard. In addition, there was no phytotoxicity observed with the use of hybrid nanomaterials in the field. These results suggest the potential of novel magnesium-copper-based hybrid nanomaterials to manage copper-tolerant bacterial pathogens.
番茄细菌性斑点病（Bacterial spot of tomato，BST）主要由 （）引起，在炎热潮湿的环境中是最具破坏性的疾病之一。细菌对铜基杀真菌剂和抗生素的抗性使得疾病管理极具挑战性。这就需要替代新的解决方案来管理这种疾病。在这项研究中，我们使用了两种新型的混合铜和镁纳米材料，分别标记为镁双层（magnesium double-coated，Mg-Db）和镁铜（magnesium-copper，Mg-Cu），来管理 BST。在体外实验中，暴露于 500μg/ml 的 Mg-Db 和 Mg-Cu 4 小时后，没有存活的细胞被回收，而 100 和 200μg/ml 需要 24 小时的暴露才能完全抑制。在使用活/死细胞染色法和荧光显微镜的活力测定中，铜耐受 细胞在 500μg/ml 的 Mg-Cu 和 Mg-Db 纳米材料作用下 4 小时内被杀死，但铜氢氧化物（Kocide 3000）不能。在温室中，与微米级商业铜杀真菌剂 Kocide 3000 和种植者标准（铜氢氧化物+代森锰锌）相比，100 至 500μg/ml 的 Mg-Db 和 Mg-Cu 显著降低了 BST 的严重程度（<0.05）。在田间研究中，Mg-Db 和 Mg-Cu 纳米材料在 4 次田间试验中的 2 次显著降低了疾病的严重程度。与未处理的对照相比，2020 年秋季，500μg/ml 的 Mg-Db 使 BST 的严重程度降低了 34%，而不影响产量。在田间试验中评估的最高浓度（500μg/ml）使用混合纳米材料可以将铜的使用量减少 90%，与种植者的标准相比。此外，在田间使用混合纳米材料没有观察到植物毒性。这些结果表明，新型镁铜基混合纳米材料具有管理铜耐受细菌病原体的潜力。
