Insecticidal activity of the metalloprotease AprA occurs through suppression of host cellular and humoral immunity

Seung Ah Lee, Seong Han Jang, Byung Hyun Kim, Toshio Shibata, Jinwook Yoo, Yunjin Jung, Shun-Ichiro Kawabata, Bok Luel Lee

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

The biochemical characterization of virulence factors from entomopathogenic bacteria is important to understand entomopathogen-insect molecular interactions. Pseudomonas entomophila is a typical entomopathogenic bacterium that harbors virulence factors against several insects. However, the molecular actions of these factors against host innate immune responses are not clearly elucidated. In this study, we observed that bean bugs (Riptortus pedestris) that were injected with P. entomophila were highly susceptible to this bacterium. To determine how P. entomophila counteracts the host innate immunity to survive within the insect, we purified a highly enriched protein with potential host insect-killing activity from the culture supernatant of P. entomophila. Then, a 45-kDa protein was purified to homogeneity and identified as AprA which is an alkaline zinc metalloprotease of the genus Pseudomonas by liquid chromatography mass spectrometry (LC-MS). Purified AprA showed a pronounced killing effect against host insects and suppressed both host cellular and humoral innate immunity. Furthermore, to show that AprA is an important insecticidal protein of P. entomophila, we used an aprA-deficient P. entomophila mutant strain (ΔaprA). When ΔaprA mutant cells were injected to host insects, this mutant exhibited extremely attenuated virulence. In addition, the cytotoxicity against host hemocytes and the antimicrobial peptide-degrading ability of the ΔaprA mutant were greatly decreased. These findings suggest that AprA functions as an important insecticidal protein of P. entomophila via suppression of host cellular and humoral innate immune responses.

Original languageEnglish
Pages (from-to)116-126
Number of pages11
JournalDevelopmental and Comparative Immunology
Volume81
DOIs
Publication statusPublished - Apr 1 2018

All Science Journal Classification (ASJC) codes

  • Immunology
  • Developmental Biology

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