Root-knot nematodes (Meloidogyne spp.) are notorious plant-parasitic nematodes that affect agricultural crops. These obligate soil-dwelling parasites typically maneuver the host plant physiology by forming specialized feeding cells resulting in heavy yield losses. Scant management tools are available to effectively combat this pest. In an exploratory attempt of identifying new fungal biocontrol agent(s) for M. incognita from India, a Paecilomyces tenuis isolate from rhizosphere soil was found to incur > 90% mortality of the infective second-stage juveniles (J2s) at 24 h post-exposure to the fungal filtrate with about 87% parasitization. The fungal filtrate also significantly reduced the egg hatching and host-root penetration of M. incognita under in vitro and in vivo conditions revealing its effectiveness in curbing nematode pathogenicity with positive effects on plant growth. Chromatographic analyses revealed the presence of Huperzine A (433.56 mg L⁻¹) in the P. tenuis isolate. Besides, the isolate possessed acetylcholinesterase inhibition attribute with an IC₅₀ of 2.85 ± 0.12 mg mL⁻¹ of the fungal filtrate. Further, GC-MS analysis revealed the production of other nematicidal compounds by the fungus including acetic acid. To conceptualize the mode of nematicidal action, RNA-Seq was done post-treatment of the M. incognita J2s and model worm Caenorhabditis elegans with fungal filtrate and pure Huperzine A. The transcriptomic profile unraveled the molecular intricacies underlying the nematicidal action affecting several biological pathways and developmental checkpoints of the nematode. Thus, the P. tenuis isolate offers significant potential to be used as a biocontrol agent against M. incognita along with its commercial use for Huperzine A production.

根结线虫 ( Meloidogyne spp.) 是臭名昭著的植物寄生线虫，会影响农作物。这些专性生活在土壤中的寄生虫通常通过形成专门的摄食细胞来操纵宿主植物的生理机能，从而导致严重的产量损失。可用于有效对抗这种害虫的管理工具很少。在为来自印度的南方根结线虫鉴定新的真菌生物防治剂的探索性尝试中，发现从根际土壤中分离出的拟青霉（ Paecilomyces tenuis）在感染后 24 小时会导致感染性第二阶段幼虫 (J2s) 的死亡率 > 90%。暴露于约 87% 寄生的真菌滤液。真菌滤液还显着降低了南方根结线虫的卵孵化和宿主根系穿透在体外和体内条件下，揭示了其在抑制线虫致病性方面的有效性，并对植物生长产生积极影响。色谱分析揭示在细长假单胞菌分离物中存在石杉碱甲 (433.56 mg L ^-1 ) 。此外，分离物具有乙酰胆碱酯酶抑制特性，真菌滤液的IC ₅₀为2.85 ± 0.12 mg mL ^-1。此外，GC-MS 分析揭示了真菌产生了其他杀线虫化合物，包括乙酸。为了概念化杀线虫作用的模式，RNA-Seq 在处理M. incognita J2s 和模型蠕虫秀丽隐杆线虫后进行用真菌滤液和纯石杉碱甲。转录组学特征揭示了影响线虫的几种生物途径和发育检查点的杀线虫作用背后的分子复杂性。因此，P. tenuis分离物提供了巨大的潜力，可用作对抗M. incognita的生物防治剂，以及其用于石杉碱 A 生产的商业用途。