Oosporein, an abundant metabolite in Beauveria caledonica, with a feedback induction mechanism and a role in insect virulence. Issue 8 (August 2019)

• Record Type: Journal Article
• Authors: Mc Namara, Louise; Dolan, Stephen K.; Walsh, John M.D.; Stephens, John C.; Glare, Travis R.; Kavanagh, Kevin; Griffin, Christine T.
• Is Part Of: Fungal biology. Volume 123:Issue 8(2019)
• Page Start: 601
• Page End: 610
• Publication Date: 2019-08
• Subjects: Biocontrol -- Entomopathogenic fungus -- Galleria mellonella -- Large pine weevil -- Proteomics -- Secondary metabolite; EPF entomopathogenic fungi -- LFQ label free quantitative -- OpS oosporein synthase; Mycology -- Periodicals; Fungi -- Periodicals; 579.505
• DOI: 10.1016/j.funbio.2019.01.004
• Languages: English
• ISSNs: 1878-6146

Abstract

Abstract: Oosporein was first identified from the insect pathogen Beauveria bassiana >50 y ago. Here, we investigate the insecticidal, anti-feedant and immunomodulation effects of oosporein produced by Beauveria caledonica on the forestry pest Hylobius abietis and model insect Galleria mellonella . We report a novel feedback induction mechanism regulating oosporein production in B. caledonica; exogenous oosporein induces the expression of the oosporein cluster, leading to increased abundance of oosporein biosynthetic enzymes, as shown by label-free quantitative proteomics. Oosporein did not have an anti-feedant effect on H. abietis adults – on the contrary, insects exposed to oosporein-treated food fed more than those exposed to untreated food only. Injected oosporein did not kill insect larvae but increased susceptibility of H. abietis to a subsequent infection. Oosporein did not act as a contact toxin on H. abietis adults and G. mellonella larvae at the concentrations tested. Therefore, it appears that oosporein promotes infection rather than directly killing insects; this could be mediated both by a reduction in haemocyte numbers and by alterations to the humoral immune system. This work makes a case for future research into the potential use of B. caledonica as a biocontrol agent through combinations with oosporein or with enhanced production of oosporein. Highlights: Oosporein is produced by Beauveria caledonica . Oosporein exhibits immunomodulation properties. Oosporein promotes infection rather than directly killing insects. A feedback induction mechanism regulates oosporein production in B. caledonica .