Division of Plant Pathology, ICAR-Indian Agricultural Research Institute, New Delhi, India.
Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi, India.
PLoS One. 2024 Feb 15;19(2):e0297925. doi: 10.1371/journal.pone.0297925. eCollection 2024.
Nematophagous fungi are the best alternatives to chemical nematicides for managing nematodes considering environmental health. In the current study, activity of metabolites from ten isolates of Purpureocillium lilacinum (Thom) Luangsa-ard (Hypocreales: Ophiocordycipitaceae) and two isolates of Paecilomyces variotii Bainier (Eurotiales: Trichocomaceae), were examined to inhibit the hatching of Meloidogyne incognita (Kofoid & White) Chitwood (Tylenchida: Heteroderidae) eggs. At 100%, 50%, and 25% concentrations, respectively, the culture filtrate of the isolate P. lilacinum 6887 prevented 97.55%, 90.52%, and 62.97% of egg hatching. Out of all the isolates, Pl 6887, Pl 6553, and Pl 2362 showed the greatest results in the hatching inhibition experiment.Gas chromatography-mass spectrometry (GC-MS) analysis revealed a variety of nematicidal compounds from different isolates. A total of seven nematicidal compounds, including four very potent nematicidal fatty acids were found in the isolate Pl 6553. Secondary metabolites of the same isolate possess the highest M. incognita juvenile mortality, i.e., 43.33% and 92% after 48 hrs of treatment at 100 and 200 ppm concentrations, respectively. Significant difference was observed in juvenile mortality percentage among the isolate having highest and lowest nematicidal compounds. Nematicidal fatty acids like myristic and lauric acid were found for the first time in P. lilacinum. Multiple vacuole-like droplets were found inside the unhatched eggs inoculated with the culture filtrate of isolate Pl 6887, and also in the juveniles that perished in the ethyl acetate extract of isolate Pl 6553.
考虑到环境健康，在防治线虫方面，食线虫真菌是化学杀线虫剂的最佳替代品。本研究中，测定了 10 株淡紫拟青霉（Purpureocillium lilacinum）（Hypocreales：Ophiocordycipitaceae）和 2 株哈茨木霉（Paecilomyces variotii）（Eurotiales：Trichocomaceae）分离株的代谢产物活性，以抑制南方根结线虫（Meloidogyne incognita）卵的孵化。在 100%、50%和 25%浓度下，淡紫拟青霉 6887 的培养液滤液分别阻止了 97.55%、90.52%和 62.97%的卵孵化。在所有分离株中，Pl 6887、Pl 6553 和 Pl 2362 在孵化抑制实验中表现出最大的效果。气相色谱-质谱联用（GC-MS）分析显示，不同分离株产生了多种杀线虫化合物。在 Pl 6553 分离株中发现了总共 7 种杀线虫化合物，包括 4 种非常有效的杀线虫脂肪酸。在 100 和 200ppm 浓度下，同一分离株的次生代谢物对南方根结线虫幼虫的死亡率最高，分别为 43.33%和 92%。在具有最高和最低杀线虫化合物的分离株之间，观察到幼虫死亡率百分比有显著差异。在淡紫拟青霉中首次发现了肉豆蔻酸和月桂酸等杀线虫脂肪酸。在接种 Pl 6887 培养液滤液的未孵化卵和 Pl 6553 乙酸乙酯提取物中死亡的幼虫内，发现了多个类似液泡的液滴。
