Increased Phenoloxidase Activity Constitutes the Main Defense Strategy of Trichoplusia ni Larvae against Fungal Entomopathogenic Infections

Bibliographic Details
Title: Increased Phenoloxidase Activity Constitutes the Main Defense Strategy of Trichoplusia ni Larvae against Fungal Entomopathogenic Infections
Authors: Kristin R. Duffield, Alayna M. Rosales, Ephantus J. Muturi, Robert W. Behle, José L. Ramirez
Source: Insects, Vol 14, Iss 8, p 667 (2023)
Publisher Information: MDPI AG, 2023.
Publication Year: 2023
Collection: LCC:Science
Subject Terms: entomopathogenic fungi (EPF), host immune response, host–fungal interactions, phenoloxidase cascade, insect immunity, Science
More Details: The cabbage looper Trichoplusia ni 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 T. ni larvae following exposure to two entomopathogenic fungal species: Beauveria bassiana and Cordyceps javanica. Results from our study demonstrate that T. ni 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 B. bassiana than with C. javanica. Larvae exposed to B. bassiana 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 B. bassiana infections eliciting three antimicrobial effectors (lysozyme, gloverin, and cecropin), while C. javanica only induced cecropin expression. These results provide insight into the host response strategies employed by T. ni 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.
Document Type: article
File Description: electronic resource
Language: English
ISSN: 2075-4450
Relation: https://www.mdpi.com/2075-4450/14/8/667; https://doaj.org/toc/2075-4450
DOI: 10.3390/insects14080667
Access URL: https://doaj.org/article/01eed1a49e874adc93527c29def44a43
Accession Number: edsdoj.01eed1a49e874adc93527c29def44a43
Database: Directory of Open Access Journals
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More Details
ISSN:20754450
DOI:10.3390/insects14080667
Published in:Insects
Language:English