The eicosanoid signaling pathway mediates insect immune reactions to a wide range of stimuli.This pathway begins with the biosynthesis of arachidonic acid (AA)from the hydrolysis of phospholipids catalyzed by phospholipase A2 (PLA2).We report here that the PLA2 inhibitor,dexamethasone (DEX),impaired the innate immune response including nodulation,encapsulation,and melanization in Ostriniafurnacalis larvae,while AA partially reversed these effects of DEX.We cloned a full-length complementary DNA encoding a PLA2,designated as OfsPLA2,from O.furnacalis.The open reading frame of OfsPLA2 encodes a 195-amino acid residue protein with a 22-residue signal peptide.Sequence alignment analyses indicated that O.furnacalis PLA2 might be a Group Ⅲ se-cretory PLA2.The highest transcript levels of OfsPLA2 were detected in the fat body,and its transcript levels increased dramatically after infection with Escherichia coli,Mi-crococcus luteus,or Beauveria bassiana.Recombinant OfsPLA2 significantly induced prophenoloxidase (PPO) activation in larval hemolymph in the presence of Ca2+ and en-capsulation of agarose beads.Injection of recombinant OfsPLA2 into larvae resulted in increased transcript levels of attacin,defencin,and moricin-3 genes.Our results demon-strate the involvement of the eicosanoid signaling pathway in the innate immune response of O.furnacalis larvae and provide new information about the roles of O.furnacalis se-cretory PLA2 in activating PPO and antimicrobial peptide production.

Jia-Yue Ji;Zhao-Hua Yin;Sha-Sha Zhang;Dong-Xu Shen;Chun-Ju An

Department of Entomology,College of Plant Protection,China Agricultural University,Beijing,100193,China;Jiangsu Key Laboratory of Sericutural Biology and Biotechnology,School of Biotechnology,Jiangsu University of Science and Technology,Zhenjiang,Jiangsu,212018,China;Key Laboratory of Silkworm and Mulberry Genetic Improvement,Ministry of Agriculture and Rural Affairs,Sericultural Research Institute,Chinese Academy of Agricultural Sciences,Zhenjiang,Jiangsu,212018,China

中国昆虫科学（英文版）

[1]Jia-Yue Ji;Zhao-Hua Yin;Sha-Sha Zhang;Dong-Xu Shen;Chun-Ju An-.PLA2 mediates the innate immune response in Asian corn borer,Ostrinia furnacalis)[J].中国昆虫科学（英文版）,2022(01):245-258

eicosanoid,melanization,Ostriniafurnacalis,OfsPLA2,cretory,crococcus,prophenoloxidase,capsulation,attacin,defencin,moricin

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