Cuticular lipids and silverleaf whitefly stage affect conidial germination of Beauveria bassiana and Paecilomyces fumosoroseus

James, Rosalind R.; Buckner, James S.; Freeman, Thomas

doi:10.1016/j.jip.2003.08.006

Cited by 93 publications

(48 citation statements)

References 21 publications

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“…Furthermore, varying degrees of attachment could also be due to the chemical characteristics of the epicuticle which plays an important role in determining fungal spore adhesion [43]. Hydrophobic lipids and fungistatic compounds in the outermost epicuticular wax layer can play an essential role in attachment and germination of fungal propagules [44–47]. …”

Section: Discussionmentioning

confidence: 99%

Highly specific host-pathogen interactions influence Metarhizium brunneum blastospore virulence against Culex quinquefasciatus larvae

et al. 2018

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Entomopathogenic fungi are potential biological control agents of mosquitoes. Our group observed that not all mosquitoes were equally susceptible to fungal infection and observed significant differences in virulence of different spore types. Conidiospores and blastospores were tested against Culex quinquefasciatus larvae. Blastospores are normally considered more virulent than conidia as they form germ tubes and penetrate the host integument more rapidly than conidia. However, when tested against Cx. quinquefasciatus, blastospores were less virulent than conidia. This host-fungus interaction was studied by optical, electron and atomic force microscopy (AFM). Furthermore, host immune responses and specific gene expression were investigated. Metarhizium brunneum (formerly M. anisopliae) ARSEF 4556 blastospores did not readily adhere to Culex larval integument and the main route of infection was through the gut. Adhesion forces between blastospores and Culex cuticle were significantly lower than for other insects. Larvae challenged with blastospores showed enhanced immune responses, with increased levels of phenoloxidase, glutathione-S-transferase, esterase, superoxide dismutase and lipid peroxidase activity. Interestingly, M. brunneum pathogenicity/stress-related genes were all down-regulated in blastospores exposed to Culex. Conversely, when conidia were exposed to Culex, the pathogenicity genes involved in adhesion or cuticle degradation were up-regulated. Delayed host mortality following blastospore infection of Culex was probably due to lower adhesion rates of blastospores to the cuticle and enhanced host immune responses deployed to counter infection. The results here show that subtle differences in host-pathogen interactions can be responsible for significant changes in virulence when comparing mosquito species, having important consequences for biological control strategies and the understanding of pathogenicity processes.

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Section: Discussionmentioning

confidence: 99%

Highly specific host-pathogen interactions influence Metarhizium brunneum blastospore virulence against Culex quinquefasciatus larvae

et al. 2018

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“…The underlying biochemical mechanism(s) behind such resistance and counterattempts by the fungus to overcome such defenses has remained obscure. For some insects, resistance has been attributed to the production of antimicrobial cuticular compounds (53)(54)(55). More recently there is growing evidence that some of these compounds are not produced by the insects themselves but by endogenous microbial flora, adding an interesting twist to coevolutionary scenarios (56,57).…”

Section: Discussionmentioning

confidence: 99%

Tenebrionid secretions and a fungal benzoquinone oxidoreductase form competing components of an arms race between a host and pathogen

Pedrini

Ortiz‐Urquiza

Huarte‐Bonnet

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

127

118

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Entomopathogenic fungi and their insect hosts represent a model system for examining invertebrate-pathogen coevolutionary selection processes. Here we report the characterization of competing components of an arms race consisting of insect protective antimicrobial compounds and evolving fungal mechanisms of detoxification. The insect pathogenic fungus Beauveria bassiana has a remarkably wide host range; however, some insects are resistant to fungal infection. Among resistant insects is the tenebrionid beetle Tribolium castaneum that produces benzoquinone-containing defensive secretions. Reduced fungal germination and growth was seen in media containing T. castaneum dichloromethane extracts or synthetic benzoquinone. In response to benzoquinone exposure, the fungus expresses a 1,4-benzoquinone oxidoreductase, BbbqrA, induced >40-fold. Gene knockout mutants (ΔBbbqrA) showed increased growth inhibition, whereas B. bassiana overexpressing BbbqrA (Bb::BbbqrAO) displayed increased resistance to benzoquinone compared with wild type. Increased benzoquinone reductase activity was detected in wild-type cells exposed to benzoquinone and in the overexpression strain. Heterologous expression and purification of BbBqrA in Escherichia coli confirmed NAD(P)H-dependent benzoquinone reductase activity. The ΔBbbqrA strain showed decreased virulence toward T. castaneum, whereas overexpression of BbbqrA increased mortality versus T. castaneum. No change in virulence was seen for the ΔBbbqrA or Bb::BbbqrAO strains when tested against the greater wax moth Galleria mellonella or the beetle Sitophilus oryzae, neither of which produce significant amounts of cuticular quinones. The observation that artificial overexpression of BbbqrA results in increased virulence only toward quinone-secreting insects implies the lack of strong selection or current failure of B. bassiana to counteradapt to this particular host defense throughout evolution.

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“…The epicuticle is covered by complex mixtures of lipids [22 and references reported therein], which defend insects against dehydration and probably also play some role against microorganisms [23,24,25]. However, to the best of our knowledge, antimicrobial peptides have never been reported on the epicuticle, neither for solitary nor for social insects.…”

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confidence: 99%

Dominulin A and B: Two new antibacterial peptides identified on the cuticle and in the venom of the social paper waspPolistes dominulususing MALDI-TOF, MALDI-TOF/TOF, and ESI-ion trap

Turillazzi

Mastrobuoni

Dani

et al. 2006

J. Am. Soc. Mass Spectrom.

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Two new antibacterial peptides, denominated as Dominulin A and B, have been found on the cuticle and in the venom of females of the social paper wasp Polistes dominulus. The amino acidic sequence of the two peptides, determined by mass spectrometry, is INWKKIAE VGGKIL SSL for Dominulin A (MW ϭ 1854 Da) and INWKKIAEIGKQVL SAL (MW ϭ 1909 Da) for Dominulin B. Their presence on the cuticle was confirmed using MALDI-TOF by means of micro-extractions and direct analyses on body parts. The presence in the venom and the primary structure of the dominulins suggest their classification in the mastoparans, a class of peptides found in the venom of other Aculeate hymenoptera. Their antimicrobial action against Gramϩ and GramϪ bacteria fits in the range of the best natural antimicrobial peptides. Dominulins can represent an important defense of the colony of Polistes dominulus against microbial pathogens. (J Am Soc Mass Spectrom 2006, 17, 376 -383)

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Cuticular lipids and silverleaf whitefly stage affect conidial germination of Beauveria bassiana and Paecilomyces fumosoroseus

Cited by 93 publications

References 21 publications

Highly specific host-pathogen interactions influence Metarhizium brunneum blastospore virulence against Culex quinquefasciatus larvae

Highly specific host-pathogen interactions influence Metarhizium brunneum blastospore virulence against Culex quinquefasciatus larvae

Tenebrionid secretions and a fungal benzoquinone oxidoreductase form competing components of an arms race between a host and pathogen

Dominulin A and B: Two new antibacterial peptides identified on the cuticle and in the venom of the social paper waspPolistes dominulususing MALDI-TOF, MALDI-TOF/TOF, and ESI-ion trap

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