Fusarium acid (FSA) serves as a highly sensitive biomarker for the early warning of bulb rot in Lanzhou lily caused by Fusarium oxysporum infection. Realizing its highly sensitive, accurate, and rapid detection is crucial for the early warning and control of lily bulb rot. Herein, an enzyme biosensor based on the enzyme inhibition principle was developed for the rapid detection of FSA. Firstly, chitosan-functionalized carboxylated multi-walled carbon nanotubes (CS@cMWCNTS) and gold nanoparticles (AuNPs) were modified on a bare electrode by drop coating and electrochemical deposition methods, respectively. Subsequently, dopamine β-hydroxylase (DBH) was firmly immobilized on the electrode surface through the gold-sulfur bond. Because the activity of DBH can be inhibited by FSA, which leads to a noticeable change in the signal response during the conversion of dopamine (DA) to norepinephrine (NA). Under optimized experimental conditions, the sensor exhibits an excellent linear relationship in the concentration range of 1.00 × 10−5 μg ml−1 ∼ 1.00 × 103 μg ml−1 with the correlation coefficient of 0.9856 and the detection limit is 4.60pg ml−1. Additionally, the sensor showed good stability, repeatability (RSD 1.85%), and selectivity. The method was applied to analyze FSA in the extraction from Lanzhou lily with a recovery higher than 97.59% and RSD less than 1.383%. This method enables the highly sensitive and rapid detection of FSA in real samples, and provides scientific basis and technical support for early warning of diseases and accurate implementation of prevention and control strategies in crop planting and production.
Bin Bin Huang,Ming Wei Gao,Guo Li,Ming-An Ouyang,Qi-Jian Chen
In research related to fungicides, the development of compounds from natural products with high antifungal activity has attracted considerable attention. Fusaric acid (FA), an alkaloid isolated from the metabolites of Fusarium oxysporum, is an important precursor for developing pharmacologically active herbicides. In our previous work, we reported that FA has a wide range of inhibitory activities against 14 plant pathogenic fungi. In particular, it exhibited excellent antifugal effects on Colletotrichum higginsianum (EC50 = 31.7 μg/mL). Herein, to explore the practical application in the agricultural field, the design and synthesis of three series of FA derivatives and their inhibitory activities against plant pathogenic fungi were examined. Results demonstrated that the optimized FA derivatives had excellent inhibitory activities against C. higginsianum, Helminthosporium (Harpophora maydis), and Pyricularia grisea. In particular, the inhibitory activities were considerably improved when the 5-butyl groups of FA were substituted. The EC50 of C. higginsianum and P. grisea was only 1.2 and 12.0 μg/mL when 5-butylalkyl groups were substituted with 5-([1,1′-biphenyl]-4-yl) and 5-phenyl, respectively. Moreover, the safety index of target compounds, which was obtained from the treatment index of medicines, on rice seeds was evaluated. Finally, 16 leading compounds (H4, H22–H24, H27, H29, H30–H34, H37, H45, H50, H52, and H53) were obtained; they had considerable potential for additional modification and optimization as agricultural fungicides. Moreover, three-dimensional quantitative structure–activity relationship models were developed for obtaining a systematic structure–activity relationship profile to explore the possibility of more potent FA derivatives as novel fungicides.
危险品化学品经营许可证（带存储）