Root-knot nematodes (RKNs) are pathogens that endanger a wide range of crops and cause serious global agricultural losses. In this study, we investigated metabolites of the endoparasitic fungus Harposporium anguillulae YMF1.01751, with the expectation of discovering valuable Meloidogyne incognita biocontrol compounds. Based on results obtained by a liquid chromatograph coupled to a mass spectrometer (LC-MS) of crude extracts under five culture conditions and their nematicidal activity against M. incognita, corn meal agar (CMA) medium was determined as the scale-up fermentation medium. Twelve metabolites (1–12) were isolated from the fermentation products, and compound 1 was identified to be a new cyclic tetrapeptide. The activity assay results showed that phenylacetic acid (11) had good nematicidal activity at 400 μg/mL, and the mortalities of M. incognita were 89.76% and 96.05% at 12 and 24 h, respectively, while the mortality of canthin-6-one (2) against M. incognita was 44.26% at 72 h. In addition, the results of chemotaxis activity showed that 1-(1H-indol-3-yl)ethanone (10) possessed attraction activity towards M. incognita. At the tested concentrations, cyclo-(Arg-Pro) (4) and cyclo-(Val-Ile) (7) showed an avoidant response to M. incognita. This study provides insight into the nematode-active compounds of H. anguillulae origin and offers new opportunities for the development of RKN biocontrol products.
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机译：根结线虫 （RKN） 是危害多种作物并造成严重全球农业损失的病原体。在这项研究中，我们调查了内寄生真菌 Harposporium anguillulae YMF1.01751 的代谢物，以期发现有价值的 Meloidogyne incognita 生物控制化合物。根据液相色谱仪与质谱仪 （LC-MS） 联用在五种培养条件下对粗提物及其对 M. incognita 的杀线虫活性获得的结果，确定玉米粉琼脂 （CMA） 培养基作为放大发酵培养基。从发酵产物中分离出 12 种代谢物 （1-12），化合物 1 被鉴定为一种新的环状四肽。活性测定结果显示，苯乙酸 （11） 在 400 μg/mL 时具有良好的杀线虫活性，12 h 和 24 h 时 M. incognita 的死亡率分别为 89.76% 和 96.05%，而 canthin-6-one （2） 对 M. incognita 的死亡率在 72 h 时为 44.26%。此外，趋化活性的结果表明，1-（1H-吲哚-3-基）乙酮 （10） 对 M. incognita 具有吸引力。在测试浓度下，环-（Arg-Pro） （4） 和环-（Val-Ile） （7） 显示出对 M. incognita 的回避反应。本研究提供了对 H. anguillulae 来源的线虫活性化合物的见解，并为 RKN 生物防治产品的开发提供了新的机会。
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