Abstract Cucumber (Cucumis sativus L.) is an important vegetable crop grown worldwide. However, its productivity is largely suppressed the phytopathogen Fusarium oxysporum f. sp. cucumerinum (FOC). We screened 100 isolates of Trichoderma as potential biocontrol agents against FOC. Both in vitro and in vivo methods were used, followed by the analysis of synergistic effect of cell wall degrading enzymes (CWDEs) and its secondary metabolites. In addition, molecular target of growth regulating protein of FOC (Snt2, a BAH/PHD containing transcription factor) was also studied. Of the 100 isolates of Trichoderma, 10 isolates with more than 85% inhibition rate were selected for in vivo antagonism in greenhouse experiment. Trichoderma asperellum strain CCTCC-RW0014 was found to have good biocontrol potential with high disease reduction of 71.67%. The RT-qPCR analysis revealed that the ITS copies of T. asperellum CCTCC-RW0014 were significantly higher in the cucumber roots treated with T. asperellum CCTCC-RW0014. Whereas the ITS copies of FOC declined in plants root in the presence of T. asperellum CCTCC-RW0014 and FOC. T. asperellum CCTCC-RW0014 showed high hydrolytic activity of chitin (87.5 ± 3.21%), gelatin (84.8 ± 2.56%), carboxymethyl cellulose (52.9 ± 1.23%) and pachyman (60.5 ± 2.32%). The crude enzymes; namely chitinase, cellulase, protease, and β (1–3) glucanase; were optimally active at 40 °C and pH 5.0, 30 °C and pH 6.0, 40 °C and pH 7, and 40 °C and pH 6.0 respectively. The secondary metabolites of Trichoderma extracts were determined by GC–MS and further studied for the molecular docking against target protein Snt2. Among the tested compounds, 1, 6-diphenylhexane-1,3,4,6-tetrone showed the highest C dock energy (−27.567 kacl/mol) against the target protein and this may down regulate the expression of protein Snt2. The present work concluded that T. asperellum CCTCC-RW0014 was the highly potential strain to control the FOC, providing scope for a further study on the mechanism of interaction between Trichoderma derived compounds and host plants.

中文翻译：

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木霉衍生的抗真菌代谢物和细胞壁降解酶对尖孢镰刀菌增强生物防治的协同作用。sp. 黄瓜

摘要 黄瓜（Cucumis sativus L.）是世界范围内种植的重要蔬菜作物。然而，其生产力在很大程度上受到植物病原体尖孢镰刀菌的抑制。sp. 黄瓜 (FOC)。我们筛选了 100 株木霉分离株作为针对 FOC 的潜在生物防治剂。使用体外和体内方法，然后分析细胞壁降解酶（CWDEs）及其次级代谢物的协同作用。此外，还研究了 FOC 生长调节蛋白（Snt2，一种含有 BAH/PHD 的转录因子）的分子靶点。在100株木霉属植物中，选择了10株抑制率超过85%的菌株进行温室体内拮抗实验。发现曲霉木霉菌株 CCTCC-RW0014 具有良好的生物防治潜力，疾病减少率高达 71.67%。RT-qPCR 分析显示，在用 T. asperellum CCTCC-RW0014 处理的黄瓜根中，T. asperellum CCTCC-RW0014 的 ITS 拷贝显着更高。而在 T. asperellum CCTCC-RW0014 和 FOC 存在的情况下，植物根中 FOC 的 ITS 副本下降。T. asperellum CCTCC-RW0014 显示出几丁质 (87.5 ± 3.21%)、明胶 (84.8 ± 2.56%)、羧甲基纤维素 (52.9 ± 1.23%) 和 pachyman (60.5 ± 2.32%) 的高水解活性。粗酶；即几丁质酶、纤维素酶、蛋白酶和β（1-3）葡聚糖酶；分别在 40 °C 和 pH 5.0、30 °C 和 pH 6.0、40 °C 和 pH 7 以及 40 °C 和 pH 6.0 下具有最佳活性。木霉属提取物的次级代谢产物通过 GC-MS 进行测定，并进一步研究与靶蛋白 Snt2 的分子对接。在测试的化合物中，1, 6-二苯基己烷-1,3,4, 6-丁酮对靶蛋白显示出最高的 C 坞能量 (-27.567 kacl/mol)，这可能会下调蛋白 Snt2 的表达。目前的工作得出结论，T. asperellum CCTCC-RW0014 是控制 FOC 的高潜力菌株，为进一步研究木霉衍生化合物与宿主植物之间的相互作用机制提供了空间。