Prophenoloxidase of <i>Odontotermes formosanus</i> (Shiraki) (Blattodea: Termitidae) Is a Key Gene in Melanization and Has a Defensive Role during Bacterial Infection
Melanization mediated by the prophenoloxidase (PPO)-activating system is an important innate immunity to fight pathogens in insects. In this study, the in vitro time-dependent increase in the intensity of melanization and phenoloxidase (PO) activity from the hemolymph of <i>Odontotermes formos...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2022-12-01
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| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/24/1/406 |
| Summary: | Melanization mediated by the prophenoloxidase (PPO)-activating system is an important innate immunity to fight pathogens in insects. In this study, the in vitro time-dependent increase in the intensity of melanization and phenoloxidase (PO) activity from the hemolymph of <i>Odontotermes formosanus</i> (Shiraki) challenged by pathogenic bacteria was detected. PPO is one of the key genes in melanization pathway, whereas the molecular characteristics and functions of <i>O. formosanus</i> PPO are unclear. The <i>OfPPO</i> gene was cloned and characterized. The open reading frame of <i>OfPPO</i> is 2085 bp in length and encodes a 79.497 kDa protein with 694 amino acids. A BLASTx search and phylogenetic analyses revealed that OfPPO shares a high degree of homology to the Blattodea PPOs. Moreover, real-time fluorescent quantitative PCR analysis showed that <i>OfPPO</i> is ubiquitously expressed in all castes and tissues examined, with the highest expression in workers and variable expression patterns in tissues of different termite castes. Furthermore, the expression of <i>OfPPO</i> was significantly induced in <i>O. formosanus</i> infected by pathogenic bacteria. Intriguingly, in combination with silencing of <i>OfPPO</i> expression, pathogenic bacteria challenge caused greatly increased mortality of <i>O. formosanus</i>. These results suggest that <i>OfPPO</i> plays a role in defense against bacteria and highlight the novel termite control strategy combining pathogenic bacteria application with termite PPO silencing. |
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| ISSN: | 1661-6596 1422-0067 |