Zhu Shengan, Xie Shengze, Jin Dan, Lin Dongmei, Jiao Shouhao, Fan Yanhua
College of Agronomy and Biotechnology, Southwest University, Chongqing, China.
Yibin Academy of Southwest University, Yibin, China.
Pest Manag Sci. 2025 Oct;81(10):6678-6689. doi: 10.1002/ps.70020. Epub 2025 Jun 28.
Allatotropin (AT) is a neuropeptide that plays important roles in insect physiology and immune responses. However, the immune-regulatory role of AT in Lepidopteran insects and its potential use for the virulence enhancement of insect pathogenic fungi remain unclear. This study investigates the role of AT in negatively regulating immune reactions in Lepidopteran insects and its application in the genetic engineering of the entomopathogenic fungus Beauveria bassiana.
Phylogenetic analysis showed that AT proteins are conserved across insect orders but exhibit distinct evolutionary patterns and potential functional diversities among groups. Amino acid sequence comparison revealed that the reported 13-aa mature AT sequence is conserved in Lepidopteran insects. Synthetic 13-aa AT peptide injection in Galleria mellonella larvae significantly suppressed immune gene expression, hemocyte count, and phenoloxidase activity in a concentration- and time-dependent manner. Compared to the B. bassiana wild type (Bb-WT), the AT-expressing strain (Bb::AT) exhibited enhanced virulence against G. mellonella larvae, with the median lethal time (LT) reduced by up to 23.79% and the median lethal dose (LD) reduced by 85.57%. Specifically, larvae infected with the Bb::AT strain exhibited weakened immune responses, and the fungus displayed a higher proliferation rate than in Bb-WT-infected larvae. Bb::AT strain also exhibited increased virulence against other Lepidopteran pests, including Spodoptera litura and Helicoverpa armigera.
These findings demonstrate that the neuropeptide AT can suppress immune responses in Lepidopteran insects, thereby enhancing fungal virulence. This provides valuable insights into developing more effective biological control strategies using B. bassiana to manage Lepidopteran pests. © 2025 Society of Chemical Industry.
促咽侧体素（AT）是一种神经肽，在昆虫生理和免疫反应中发挥重要作用。然而，AT在鳞翅目昆虫中的免疫调节作用及其在增强昆虫病原真菌毒力方面的潜在用途仍不清楚。本研究调查了AT在负调控鳞翅目昆虫免疫反应中的作用及其在昆虫病原真菌球孢白僵菌基因工程中的应用。
系统发育分析表明，AT蛋白在昆虫各目中保守，但在不同类群中呈现出不同的进化模式和潜在功能多样性。氨基酸序列比较显示，报道的13个氨基酸的成熟AT序列在鳞翅目昆虫中保守。向大蜡螟幼虫注射合成的13个氨基酸的AT肽以浓度和时间依赖性方式显著抑制免疫基因表达、血细胞计数和酚氧化酶活性。与球孢白僵菌野生型（Bb-WT）相比，表达AT的菌株（Bb::AT）对大蜡螟幼虫的毒力增强，中位致死时间（LT）最多缩短23.79%，中位致死剂量（LD）降低85.57%。具体而言，感染Bb::AT菌株的幼虫免疫反应减弱，该真菌的增殖率高于感染Bb-WT的幼虫。Bb::AT菌株对其他鳞翅目害虫，包括斜纹夜蛾和棉铃虫，也表现出增强的毒力。
这些发现表明神经肽AT可抑制鳞翅目昆虫的免疫反应，从而增强真菌毒力。这为利用球孢白僵菌开发更有效的生物防治策略来管理鳞翅目害虫提供了有价值的见解。© 2025化学工业协会。
