Duffield Kristin R, Rosales Alayna M, Muturi Ephantus J, Behle Robert W, Ramirez José L
USDA-ARS, National Center for Agricultural Utilization Research, Crop BioProtection Research Unit, 1815 N. University St., Peoria, IL 61604, USA.
Biology Department, Bradley University, Peoria, IL 61604, USA.
Insects. 2023 Jul 25;14(8):667. doi: 10.3390/insects14080667.
The cabbage looper is an important agricultural pest worldwide and is frequently used as a model organism for assessing entomopathogenic fungi virulence, though few studies have measured the host response repertoire to fungal biocontrol agents. Here, we quantified the immune response of larvae following exposure to two entomopathogenic fungal species: and . Results from our study demonstrate that larvae exposed to fungal entomopathogens had higher total phenoloxidase activity compared to controls, indicating that the melanization cascade is one of the main immune components driving defense against fungal infection and contrasting observations from other insect-fungi interaction studies. We also observed differences in host response depending on the species of entomopathogenic fungi, with significantly higher induction observed during infections with than with . Larvae exposed to had an increased expression of genes involved in prophenoloxidase response and the Imd, JNK, and Jak/STAT immune signaling pathways. Our results indicate a notable absence of Toll pathway-related responses, further contrasting results to other insect-fungi pathosystems. Important differences were also observed in the induction of antimicrobial effectors, with infections eliciting three antimicrobial effectors (lysozyme, gloverin, and cecropin), while only induced cecropin expression. These results provide insight into the host response strategies employed by for protection against entomopathogenic fungi and increase our understanding of insect-fungal entomopathogen interactions, aiding in the design of more effective microbial control strategies for this important agricultural pest.
小菜蛾是一种在全球范围内重要的农业害虫，常被用作评估昆虫病原真菌毒力的模式生物，尽管很少有研究测量宿主对真菌生物防治剂的反应谱。在此，我们量化了小菜蛾幼虫在接触两种昆虫病原真菌（[真菌名称1]和[真菌名称2]）后的免疫反应。我们的研究结果表明，与对照组相比，接触真菌病原的小菜蛾幼虫具有更高的总酚氧化酶活性，这表明黑化级联反应是驱动对真菌感染防御的主要免疫成分之一，这与其他昆虫 - 真菌相互作用研究的观察结果形成对比。我们还观察到宿主反应因昆虫病原真菌的种类而异，感染[真菌名称1]期间的诱导作用明显高于感染[真菌名称2]。接触[真菌名称1]的幼虫参与前酚氧化酶反应以及Imd、JNK和Jak/STAT免疫信号通路的基因表达增加。我们的结果表明明显缺乏与Toll途径相关的反应，这进一步与其他昆虫 - 真菌病理系统的结果形成对比。在抗菌效应物的诱导方面也观察到重要差异，感染[真菌名称1]引发三种抗菌效应物（溶菌酶、gloverin和天蚕素），而感染[真菌名称2]仅诱导天蚕素表达。这些结果为小菜蛾用于抵御昆虫病原真菌的宿主反应策略提供了见解，并增进了我们对昆虫 - 真菌病原相互作用的理解，有助于设计针对这种重要农业害虫更有效的微生物控制策略。
