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A trypsin inhibitor-like protein secreted by Cotesia vestalis teratocytes inhibits hemolymph prophenoloxidase activation of Plutella xylostella
- Gu, Qi-juan, Zhou, Shi-min, Zhou, Yue-nan, Huang, Jian-hua, Shi, Min, Chen, Xue-xin
- Journal of insect physiology 2019 v.116 pp. 41-48
- Cotesia, Plutella xylostella, dose response, endoparasitoids, genes, hemolymph, humoral immunity, immune response, insect physiology, melanization, prophenoloxidase, teratocytes, trypsin, wasps
- To establish successful infections, endoparasitoid wasps must develop strategies to evade immune responses of the host. Here, we identified and characterized a teratocytes-expressed gene encoding a trypsin inhibitor-like protein containing a cysteine-rich domain from Cotesia vestalis, CvT-TIL. CvT-TIL had a high expression level during the later developmental stage of teratocytes and was secreted into host hemolymph. Further experiments showed CvT-TIL strongly suppressed the prophenoloxidase activation of host hemolymph in a dose-dependent manner by interacting with PxPAP3 of PO cascade. Our results not only provide evidence for an inhibition between CvT-TIL gene and the host’s melanization activity, but also expand our knowledge about the mechanisms by which parasitoids regulate humoral immunity of the host.