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Ji JY, Yin ZH, Zhang SS, Shen DX, An CJ. PLA 2 mediates the innate immune response in Asian corn borer, Ostrinia furnacalis. Insect Sci 2022; 29:245-258. [PMID: 34080301 DOI: 10.1111/1744-7917.12932] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 03/27/2021] [Accepted: 04/05/2021] [Indexed: 06/12/2023]
Abstract
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 Ostrinia furnacalis 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 secretory PLA2 . The highest transcript levels of OfsPLA2 were detected in the fat body, and its transcript levels increased dramatically after infection with Escherichia coli, Micrococcus luteus, or Beauveria bassiana. Recombinant OfsPLA2 significantly induced prophenoloxidase (PPO) activation in larval hemolymph in the presence of Ca2+ and encapsulation of agarose beads. Injection of recombinant OfsPLA2 into larvae resulted in increased transcript levels of attacin, defencin, and moricin-3 genes. Our results demonstrate 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 secretory PLA2 in activating PPO and antimicrobial peptide production.
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Affiliation(s)
- Jia-Yue Ji
- Department of Entomology, College of Plant Protection, China Agricultural University, Beijing, 100193, China
| | - Zhao-Hua Yin
- Department of Entomology, College of Plant Protection, China Agricultural University, Beijing, 100193, China
| | - Sha-Sha Zhang
- Department of Entomology, College of Plant Protection, China Agricultural University, Beijing, 100193, China
| | - Dong-Xu Shen
- 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
| | - Chun-Ju An
- Department of Entomology, College of Plant Protection, China Agricultural University, Beijing, 100193, China
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