Building upon previous structure–activity relationships about the fungicidal amide and hydrazide lead structures, 24 novel amide-hydrazide compounds were designed and synthesized with L-isoleucine as the initial skeleton to explore the impact of substituents in the hydrazide bridge on the fungicidal activity. Among these compounds, A5 exhibited excellent and broad spectrum inhibitory activity, along with satisfactory in vivo protective efficiency against R. solani at concentrations of 200 and 50 μg·mL^–1. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations revealed that compound A5 induced significant morphological changes in the R. solani mycelium coupled with vacuole rupture and cytoplasmic inhomogeneity in cellular structures. Transcriptomic and metabolomic analyses indicated that, following A5 treatment, the differentially expressed genes and metabolites were significantly enriched in carbohydrate metabolism-related pathways as well as in lipid metabolism-associated pathways, including glycerophospholipid metabolism, steroid biosynthesis, arachidonic acid metabolism, and sphingolipid metabolism. Additionally, compound A5 demonstrated low toxicity to zebrafish, with survival rates of 100% and 60% at concentrations of 1 and 10 μg·mL^–1, respectively, over a period of 7 days. The above results provide theoretical guidance for the development of novel green hydrazide fungicidal candidates.

中文翻译：

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L-异亮氨酸衍生的酰胺酰肼化合物被评价为一种新型潜在农业杀菌剂


基于先前关于杀真菌酰胺和酰肼铅结构的构效关系，以 L-异亮氨酸为初始骨架设计并合成了 24 种新型酰胺酰肼化合物，以探索酰肼桥中取代基对杀菌活性的影响。在这些化合物中，A5 表现出优异的广谱抑制活性，并且在 200 和 50 μg·mL^–1 的浓度下对立枯菌具有令人满意的体内保护效率。扫描电子显微镜 （SEM） 和透射电子显微镜 （TEM） 观察显示，化合物 A5 诱导 R. solani 菌丝体发生显着形态变化，并伴有细胞结构中的液泡破裂和细胞质不均匀性。转录组学和代谢组学分析表明，A5 处理后，差异表达基因和代谢物显著富集于碳水化合物代谢相关途径以及脂质代谢相关途径，包括甘油磷脂代谢、类固醇生物合成、花生四烯酸代谢和鞘脂代谢。此外，化合物 A5 对斑马鱼的毒性较低，在 1 μg·mL^–1 浓度下，7 天的存活率分别为 100% 和 60%。以上结果为新型绿色酰肼杀真菌候选药物的开发提供了理论指导。