Jiali Yang,Tengfei Wang,Jianbing Di,Yaping Liu,Xiaoling Hao,Yu Wang
Summary Although several studies have shown the ability of l -glutamate (glutamate) to mitigate the stress imposed by pathogens, the underlying mechanism is still in its infancy. To gain further knowledge, this study focussed on the effect of glutamate on primary nitrogen and carbon metabolisms during apple- Penicillium expansum interaction. The obtained result showed that glutamate could effectively restrict blue mould rot development in apples, but had no direct impact on fungal growth in vitro . The application of glutamate increased the level of nitrogen in apples, resulting in a disrupted balance of carbon and nitrogen. Consistently, the key enzymes glutamine synthetase (GS) and glutamate synthase (GOGAT) involved in the GS/GOGAT cycle, and the deaminating activity of glutamate dehydrogenase (GDH), forming 2-oxoglutarate and ammonium from glutamate, were promptly stimulated by glutamate. Interestingly, glutamate led to considerable consumption of the tricarboxylic acid (TCA) cycle intermediates, such as isocitric acid and citric acid, accompanied by the enhancement of malate dehydrogenase and succinate dehydrogenase activities. Collectively, exogenous application of glutamate might confer blue mould resistance in apples, at least in part, by redirecting host’s primary nitrogen and carbon metabolisms, such as the activation of the GS/GOGAT cycle, deaminating activity of GDH and the TCA cycle.
Jun Liu,Wenjing Wang,Huiwen Liu,Yaoliang Zhou,Haibo Zhang,Xiaohai Zhou
Herein, amino-epoxy supports were innovatively imported onto magnetic nanoparticles (Fe3O4–polymer hybrid nanospheres) for immobilizing enzymes. This new support has a coating layer with dual functional groups (epoxy and amino-epoxy). Consequently, this support has great anionic exchange power and a high number of epoxy groups. The acquired immobilized Penicillium expansum lipase in combination with this heterofunctional support represents a novel class of heterogeneous catalyst towards the synthesis of 1,3-dibutylurea from ethylene carbonate and butylamine, which has not been very commonly catalyzed by enzymes. After optimization of the reaction conditions, the yield of 1,3-dibutylurea was 77% under solvent free conditions at 60 °C. Moreover, after completion of reaction, the catalyst was simply recovered by an external conventional magnet and recycled without significant loss in the catalytic activity (up to ten cycles).
Postharvest diseases caused by fungal pathogens remain a major constraint on fruit storage and quality. Prochloraz (PRO) is widely used for disease control, but its practical application is limited by poor water solubility, relatively high toxicity, and the absence of antioxidant activity. In this study, three PRO-based hydrogen-bonded formulations were prepared using salicylic acid (SA), ascorbic acid (AA), or sorbic acid (SOR) as co-formers at a 1:1 molar ratio. The formulations were characterized by1H NMR, and their physicochemical properties, antifungal activity, disease control efficacy, and acute toxicity to zebrafish larvae were evaluated. All three formulations formed through hydrogen bonding and showed improved water solubility compared with pure PRO. PRO-SA exhibited the strongest antifungal activity againstPenicillium expansum(60.57% reduction in EC50) and the best disease control on Korla fragrant pears at 400 mg/L. PRO-AA showed the greatest reduction in acute toxicity to zebrafish larvae (8.04-fold) and a 54-fold increase in water solubility. PRO-SOR provided a balanced improvement in antifungal activity (41.33% reduction in EC50) and moderate toxicity reduction (1.48-fold). These results indicate that the choice of co-former determines the functional profile of PRO-based formulations, allowing tailored optimization for antifungal efficacy, reduced acute toxicity, or a balanced combination. This work offers a practical strategy for improving the performance of existing fungicides.
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