College of Plant Protection, Shanxi Agricultural University, Taiyuan 030031, Shanxi, China; State Key Laboratory of Sustainable Dryland Agriculture (in preparation), Shanxi Agricultural University, Taiyuan 030031, Shanxi, China.
College of Plant Protection, Shanxi Agricultural University, Taiyuan 030031, Shanxi, China.
Pestic Biochem Physiol. 2024 Sep;204:106076. doi: 10.1016/j.pestbp.2024.106076. Epub 2024 Aug 5.
Cordyceps javanica has been registered as a fungal insecticide in several countries. However, little is known about whether metabolic toxins are involved in the insecticidal process. In this research, we assessed the insecticidal activity of the fermentation broth of C. javanica. Myzus persicae mortality differed when exposed to the metabolized C. javanica broths at 3 days post fermentation (DPF) and 5 DPF. Comparison of the metabolic fluid at 3 DPF and 5 DPF revealed a key alkaloid, heteratisine, which was found to have insecticidal activity and acetylcholinesterase (AChE) inhibitory activity. Heteratisine has high insecticidal activity against adult M. persicae, the absolute 50% lethal concentration (LC) was only 0.2272 mg/L. Heteratisine showed high inhibitory activity on AChE with the 50% maximal inhibitory concentration (IC) of 76.69 μM. Molecular docking and dynamic simulations showed that heteratisine conjugation occurs at the peripheral anionic site (PAS) of the AChE of M. persicae, leading to suppression of enzyme activity. Heteratisine was rarely found in fungal metabolites, which helps us to understand the complex and elaborate insecticidal mechanism of C. javanica.
蛹虫草已在多个国家注册为真菌杀虫剂。然而，对于代谢毒素是否参与杀虫过程知之甚少。在这项研究中，我们评估了蛹虫草发酵液的杀虫活性。在发酵后 3 天（DPF）和 5 DPF 时，接触代谢处理的蛹虫草发酵液的烟粉虱死亡率不同。比较 3 DPF 和 5 DPF 的代谢液发现了一种关键的生物碱——异麦角碱，具有杀虫活性和乙酰胆碱酯酶（AChE）抑制活性。异麦角碱对烟粉虱成虫具有很高的杀虫活性，绝对半数致死浓度（LC）仅为 0.2272 mg/L。异麦角碱对 AChE 表现出高抑制活性，最大抑制浓度（IC）为 76.69 μM。分子对接和动态模拟表明，异麦角碱与烟粉虱 AChE 的外周阴离子结合位点（PAS）发生结合，导致酶活性抑制。异麦角碱在真菌代谢物中很少见，这有助于我们理解蛹虫草复杂而精细的杀虫机制。
