Cuticle‐degrading proteases and toxins as virulence markers of <i>Beauveria bassiana</i> (Balsamo) Vuillemin

Cito, Annarita; Barzanti, Gian Paolo; Strangi, Agostino; Francardi, Valeria; Zanfini, Assunta; Dreassi, Elena

doi:10.1002/jobm.201600022

Cited by 17 publications

(14 citation statements)

References 34 publications

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“…It has been used as a biological control agent of various arthropod pests for many years [31][32][33]. The pathogenesis and virulence of Beauveria isolates is connected with the production of toxicogenic metabolites, antioxidant enzymes and primarily extracellular cuticle-degrading enzymes such as chitinases, lipases, and proteases [33,34]. Since B. bassiana genome sequence is already known [35] there is a lot of interest in recognition of genes involved in its pathogenesis and virulence [32,36].…”

Section: Introductionmentioning

confidence: 99%

Entomopathogenic Filamentous Fungi as Biocatalysts in Glycosylation of Methylflavonoids

et al. 2020

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Flavonoids are known for their numerous biological activities; however, their pharmacological application is limited by poor bioavailability. Glycosides are usually more stable and more soluble in water and in this form, flavonoids are present in nature. Likewise, the presence of the methyl group in the flavonoid skeleton results in facilitated absorption and greater bioavailability. Entomopathogenic filamentous fungi are effective in the biotransformation of flavonoids; they are known especially for efficient glycosylation. In the current study we used strains of Beauveria bassiana KCH J1.5 and Isaria fumosorosea KCH J2 to biotransform flavonoids with a single methyl group. 2′-Hydroxy-5′-methylchalcone was biotransformed by both strains into 2′-hydroxy-5′-methylchalcone 3-O-β-D-(4″-O-methyl)-glucopyranoside. In the culture of B. bassiana KCH J1.5 four products were obtained from 6-methylflavanone: 4′-hydroxy-6-methylflavanone 3′-O-β-D-(4″-O-methyl)-glucopyranoside; 4′-hydroxyflavanone 6-methylene-O-β-D-(4″-O-methyl)-glucopyranoside; 6-hydroxymethylflavanone 3′-O-β-D-(4″-O-methyl)-glucopyranoside and 4′-hydroxy-6-hydroxymethylflavanone 3′-O-β-D-(4″-O-methyl)-glucopyranoside. Biotransformation with I. fumosorosea KCH J2 as a biocatalyst resulted in the formation of 6-methylflavanone 4′-O-β-D-(4″-O-methyl)-glucopyranoside and 2-phenyl-6-methylchromane 4-O-β-D-(4″-O-methyl)-glucopyranoside. All of these flavonoids can be used in biological activity tests and can be useful in studies concerning structure—bioactivity relationships.

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Section: Introductionmentioning

confidence: 99%

Entomopathogenic Filamentous Fungi as Biocatalysts in Glycosylation of Methylflavonoids

et al. 2020

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“…However, in the present study, our data show that the protease activity of B. bassiana ΔBbmsn2 on R. microplus cuticle decreased in the Msn2 mutant. It is known that the production of (total) protease activity can vary significantly according to the composition of host cuticle ( Cito et al., 2016 ), which may induce or inhibit fungal development ( Ment et al., 2012 ). Additionally, Santi et al.…”

Section: Discussionmentioning

confidence: 99%

“…However, in the present study, our data show that the protease activity of B. bassiana DBbmsn2 on R. microplus cuticle decreased in the Msn2 mutant. It is known that the production of (total) protease activity can vary significantly according to the composition of host cuticle (Cito et al, 2016), which may induce or inhibit fungal development (Ment et al, 2012). Additionally, Santi et al (2019) identified 50 proteins involved in the infection process, which were produced by B. bassiana cultured in media supplemented with cuticles derived from R. microplus, but not produced in media supplemented with glucose only.…”

Section: Treatment By Inoculationmentioning

confidence: 99%

The Msn2 Transcription Factor Regulates Acaricidal Virulence in the Fungal Pathogen Beauveria bassiana

Muniz

Ribeiro-Silva

Arruda

et al. 2021

Front. Cell. Infect. Microbiol.

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Beauveria bassiana holds promise as a feasible biological control agent for tick control. The B. bassiana stress–response transcription factor Msn2 is known to contribute to fungal growth, conidiogenesis, stress–response and virulence towards insects; however, little is known concerning whether Msn2 is involved in infection across Arthropoda classes. We evaluated the effects of Msn2 on B. bassiana virulence against Rhipicephalus microplus (Acari, Ixodidae) using wild-type, targeted gene knockout (ΔBbmsn2) and complemented mutant (ΔBbmsn2/Bbmsn2) strains. Reproductive parameters of R. microplus engorged females treated topically or by an intra-hemocoel injection of conidial suspensions were assessed. Treated cuticles of engorged females were analyzed by microscopy, and proteolytic activity of B. bassiana on cuticles was assessed. Topically treated engorged females showed high mean larval hatching (>84%) in control and ΔBbmsn2 treatments, whereas treatment with the wild-type or ΔBbmsn2/Bbmsn2 strains resulted in significantly decreased (lowered egg viability) larval hatching. Percent control of R. microplus topically treated with ΔBbmsn2 was lower than in the groups treated with wild-type (56.1%) or ΔBbmsn2/Bbmsn2 strains. However, no differences on reproductive parameters were detected when R. microplus were treated by intra-hemocoel injection using low (800 conidia/tick) doses for all strains tested; R. microplus injected with high doses of wild-type or mutant strains (106 conidia/tick) died before laying eggs (~48 h after treatment). SEM analyses of B. bassiana infection showed similar conidial germination and formation of pseudo-appressoria on tick cuticle. Histological sections of ticks treated with the wild-type or ΔBbmsn2/Bbmsn2 strains showed fungal penetration through the cuticle, and into the tick interior. Hyphae of ΔBbmsn2, however, did not appear to penetrate or breach the tick exocuticle 120 h after treatment. Protease activity was lower on tick cuticles treated with ΔBbmsn2 than those treated with the wild-type or ΔBbmsn2/Bbmsn2 strains. These data show that loss of the Msn2 transcription factor reduced B. bassiana virulence against R. microplus, but did not interfere with conidial germination, appressoria formation or sporulation on tick cadavers, and plays only a minimal role once the cuticle is breached. Our results indicate that the BbMsn2 transcription factor acts mainly during the fungal penetration process and that decreased protease production may be one mechanism that contributes to the inability of the mutant strain to breach the tick cuticle.

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“…Enzymatic and mechanical pressure enables B. bassiana to destroy host cuticle proteins. However, the fungus also synthetizes toxic nonenzymatic compounds such as beauvericin and basianolide that speed the infestation process (Cito et al, 2016). Furthermore, other traits such as conidial viability, germination speed, hyphal growth rate and pathogenicity are influenced by environmental factors namely temperature and relative humididy and thereby the fungal efficacy (Liu et al, 2003).…”

Section: Yield (Kg/ha)mentioning

confidence: 99%

Management of the legume pod borer Maruca vitrata Fabricius (Lepidoptera: Crambidae) with field applications of the entomopathogenic fungus, Beauveria bassiana and a mixed formulation of the baculovirus MaviMNPV with emulsifiable neem oil

Toffa¹,

Loko²,

Kpindou³

et al. 2020

Afr. J. Agric. Res.

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The present study assessed the effectiveness of the entomopathogen fungus Beauveria bassiana in comparison with neem oil combined with the baculovirus MaviMNPV and a synthetic insecticide deltamethrin for the control of Maruca vitrata Fabricius under field conditions. The trial was conducted in six villages at Glazoue and Djakotomey, two districts in Benin. Four treatments consisting of (1) untreated control, (2) neem + MaviMNPV, (3) B. bassiana and (4) deltamethrin were arranged in a complete randomized block design with three replicates. Reproductive organs of cowpea plants were sampled for estimating population of M. vitrata. In spite of the importance between-field variations observed, bio-pesticides significantly reduced the population density of M. vitrata as well as its damage level. Similarly, grain yields were improved in sprayed cowpea compared to the untreated control, regardless of the experimental zone. In Glazoue, yields ranged from 724.06 ± 5.04 kg/ha (deltamethrin) to 933.03 ± 8.7 kg/ha (B. bassiana). In Djakotomey, 649.1±4.7, 611.07±5.1, 583.19±4.04 and 217.11±3.9 kg/ha were recorded for deltamethrin, B. bassiana, neem + baculovirus, and untreated control, respectively. The possibilities of the using bio-pesticides as efficient IPM components in cowpea are discussed.

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Cuticle‐degrading proteases and toxins as virulence markers of Beauveria bassiana (Balsamo) Vuillemin

Cited by 17 publications

References 34 publications

Entomopathogenic Filamentous Fungi as Biocatalysts in Glycosylation of Methylflavonoids

Entomopathogenic Filamentous Fungi as Biocatalysts in Glycosylation of Methylflavonoids

The Msn2 Transcription Factor Regulates Acaricidal Virulence in the Fungal Pathogen Beauveria bassiana

Management of the legume pod borer Maruca vitrata Fabricius (Lepidoptera: Crambidae) with field applications of the entomopathogenic fungus, Beauveria bassiana and a mixed formulation of the baculovirus MaviMNPV with emulsifiable neem oil

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