The effect of entomopathogenic fungal culture filtrate on the immune response of the greater wax moth, Galleria mellonella

Abstract

Galleria mellonella is a well-established model species regularly employed in the study of the insect immune response at cellular and humoral levels to investigate fungal pathogenesis and biocontrol agents. A cellular and proteomic analysis of the effect of culture filtrate of three entomopathogenic fungi (EPF) species on the immune system of G. mellonella was performed. Treatment with Beauveria caledonica and Metarhizium anisopliae 96h culture filtrate facilitated a significantly increased yeast cell density in larvae (3-fold and 3.8-fold, respectively). Larvae co-injected with either M. anisopliae or B. caledonica culture filtrate and Candida albicans showed significantly increased mortality. The same was not seen for larvae injected with Beauveria bassiana filtrate. Together these results suggest that B. caledonica and M. anisopliae filtrate are modulating the insect immune system allowing a subsequent pathogen to proliferate. B. caledonica and M. anisopliae culture filtrates impact upon the larval prophenoloxidase (ProPO) cascade (e.g. ProPO activating factor 3 and proPO activating enzyme 3 were increased in abundance relative to controls), while B. bassiana treated larvae displayed higher abundances of alpha-esterase when compared to control larvae (2.4-fold greater) and larvae treated with M. anisopliae and B. caledonica. Treatment with EPF culture filtrate had a significant effect on antimicrobial peptide abundances particularly in M. anisopliae treated larvae where cecropin-D precursor, hemolin and gloverin were differentially abundant in comparison to controls. Differences in proteomic profiles for different treatments may reflect or even partially explain the differences in their immunomodulatory potential. Screening EPF for their ability to modulate the insect immune response represents a means of assessing EPF for use as biocontrol agents, particularly if the goal is to use them in combination with other control agents. Additionally EPF represent a valuable resource pool in our search for natural products with insect immunomodulatory and biocontrol properties.

The effect of entomopathogenic fungal culture filtrate on the immune response and haemolymph proteome of the large pine weevil, Hylobius abietis

“…The fact that the EPF of the different fungal species alters different members of these cascades may explain the different levels of immunomodulation observed in the cellular bioassays. Interestingly similar observations were made by Mc Namara et al (2017) who showed that the filtrate of M. brunneum and B. caledonica also altered the abundance of serine proteases and serpins in the haemolymph of G. mellonella larvae highlight potentially conserved immunomodulatory effects of the excretory/secretory products of entomopathogenic fungi.…”

“…. mellonella larvae injected with M. brunneum and B. caledonica there were alterations in abundance of peptidoglycan recognition-like (due to M. brunneum) and β-1,3-GBP and two peptidoglycan recognition proteins (due to B. caledonica)(Mc Namara et al 2017). Insects can differentiate between major groups of microbes using pattern recognition receptor (PRRs) such as PGRPs, hemolin and β-1,3-GBP.…”

Clinical strains of Lactobacillus reduce the filamentation of Candida albicans and protect Galleria mellonella against experimental candidiasis

“…Among these models, the facile inoculum delivery and handling of G. mellonella makes it a desirable model for the study of fungal pathogenesis (Fuchs et al 2010;Junqueira 2012). Furthermore, the immune system of G. mellonella possesses a number of structural and functional similarities to the innate immune system of mammals (Bergin et al 2003;Bergin et al 2006;Mc Namara et al 2017).…”

Evaluation of the Effectiveness of Some Entomopathogenic Fungi on the Greater Wax Moth Larvae, Galleria mellonella (L.) (Lepidoptera: galleriidae)

“…Treated the larvae of E. insulana and P. gossypiella using T. harzianum spores caused moderately high mortality for insect treatment, respectively (El-Massry et al, 2016). Others reported that B. bassiana can be used as biocontrol agents, the treated of G. Mellonella with culture filtrate of B. caledonica and M. anisopliae showed a significant increased larval mortality (Namara et al, 2017).…”

“…(2014). In Egypt, it was found that T. harzianum liquid filtrate and spores had to produce a large mortality rate and caused significant reduction in adult emergence significant effect on the larvae of Earias insulana and Pectinophora gossypiella caused more mortality rate for the tested insects (El-Massry et al, 2016).The treated G. mellonella with B. caledonica and M. anisopliae caused a significantly increased yeast cell density and increased larval mortality (Namara et al, 2017). Trichoderma spp.…”