Chitinolytic enzymes contribute to the pathogenicity of Aliivibrio salmonicida LFI1238 in the invasive phase of cold-water vibriosis

• Published in: BMC Microbiology
• Main Authors: Anna Skåne, Per Kristian Edvardsen, Gabriele Cordara, Jennifer Sarah Maria Loose, Kira Daryl Leitl, Ute Krengel, Henning Sørum, Fatemeh Askarian, Gustav Vaaje-Kolstad
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2022
• Subjects: lytic polysaccharide monooxygenase; LPMO; virulence; aliivibrio salmonicida; chitin; cold water vibriosis; Microbiology; QR1-502; Atlantic salmon; Gadus morhua; Salmo salar
• Online Access: https://doi.org/10.1186/s12866-022-02590-2; https://doaj.org/article/edc6e20bb8f54066ad708dbb7c51df96

Abstract Background Aliivibrio salmonicida is the causative agent of cold-water vibriosis in salmonids (Oncorhynchus mykiss and Salmo salar L.) and gadidae (Gadus morhua L.). Virulence-associated factors that are essential for the full spectrum of A. salmonicida pathogenicity are largely unknown. Chitin-active lytic polysaccharide monooxygenases (LPMOs) have been indicated to play roles in both chitin degradation and virulence in a variety of pathogenic bacteria but are largely unexplored in this context. Results In the present study we investigated the role of LPMOs in the pathogenicity of A. salmonicida LFI238 in Atlantic salmon (Salmo salar L.). In vivo challenge experiments using isogenic deletion mutants of the two LPMOs encoding genes AsLPMO10A and AsLPMO10B, showed that both LPMOs, and in particular AsLPMO10B, were important in the invasive phase of cold-water vibriosis. Crystallographic analysis of the AsLPMO10B AA10 LPMO domain (to 1.4 Å resolution) revealed high structural similarity to viral fusolin, an LPMO known to enhance the virulence of insecticidal agents. Finally, exposure to Atlantic salmon serum resulted in substantial proteome re-organization of the A. salmonicida LPMO deletion variants compared to the wild type strain, indicating the struggle of the bacterium to adapt to the host immune components in the absence of the LPMOs. Conclusion The present study consolidates the role of LPMOs in virulence and demonstrates that such enzymes may have more than one function.