Exploring secretory signal sequences useful in excreting recombinant proteins in Beauveria bassiana as biocontrol fungus.

Entomopathogenic fungi excrete a group of proteins to assimilate nutrients and defeat the host immune defense. Functional secretory signal sequences are needed for efficient secretion of the virulence-related proteins in recombinant strain. In this study, secretome analysis was used to explore the secreted proteins of Beauveria bassiana.

Unlocking the Siderophore Biosynthesis Pathway and Its Biological Functions in the Fungal Insect Pathogen .

Siderophores are small molecule iron chelators. The entomopathogenic fungus produces a plethora of siderophores under iron-limiting conditions. In this study, a siderophore biosynthesis pathway, akin to the general pathway observed in filamentous fungi, was revealed in .

S-Allyl-L-cysteine (SAC) inhibits copper-induced apoptosis and cuproptosis to alleviate cardiomyocyte injury.

Cardiomyocyte injury is closely related to various myocardial diseases, and S-Allyl-L-cysteine (SAC) has been found to have myocardial protective effects, but its mechanism is currently unclear. Meanwhile, copper also has various physiological functions, and this study found that copper inhibited cell viability in a concentration and time-dependent manner, and was associated with multiple modes of death. Elesclomol plus CuCl (ES + Cu) significantly inhibited cell viability, and this effect could only be blocked by copper chelator TTM, indicating that "ES + Cu" induced cuproptosis in cardiomyocytes.

Comparative Transcriptomics of the Entomopathogenic Fungus Beauveria bassiana Grown on Aerial Surface and in Liquid Environment.

Beauveria bassiana, the causative agent of arthropod, proliferates in the host hemolymph (liquid environment) and shits to saprotrophic growth on the host cadaver (aerial surface). In this study, we used transcriptomic analysis to compare the gene expression modes between these two growth phases. Of 10,366 total predicted genes in B.

Cla4A, a Novel Regulator of Gene Expression Networks Required for Asexual and Insect-Pathogenic Lifecycles of .

Cla4, an orthologous p21-activated kinase crucial for non-entomopathogenic fungal lifestyles, has two paralogs (Cla4A/B) functionally unknown in hypocrealean entomopathogens. Here, we report a regulatory role of Cla4A in gene expression networks of required for asexual and entomopathogenic lifecycles while Cla4B is functionally redundant. The deletion of resulted in severe growth defects, reduced stress tolerance, delayed conidiation, altered conidiation mode, impaired conidial quality, and abolished pathogenicity through cuticular penetration, contrasting with no phenotype affected by deletion.

Photoreactivation Activities of Rad5, Rad16A and Rad16B Help to Recover from Solar Ultraviolet Damage.

In budding yeast, Rad5 and Rad7-Rad16 play respective roles in the error-free post-replication repair and nucleotide excision repair of ultraviolet-induced DNA damage; however, their homologs have not yet been studied in non-yeast fungi. In the fungus , a deficiency in the Rad7 homolog, Rad5 ortholog and two Rad16 paralogs (Rad16A/B) instituted an ability to help the insect-pathogenic fungus to recover from solar UVB damage through photoreactivation. The fungal lifecycle-related phenotypes were not altered in the absence of , or while severe defects in growth and conidiation were caused by the double deletion of and .

Two ferrous iron transporter-like proteins independently participate in asexual development under iron limitation and virulence in Beauveria bassiana.

Reductive assimilation pathway involves ferric reductase and ferrous iron transporter, which is integral for fungal iron acquisition. A family of ferric reductase-like proteins has been functionally characterized in the filamentous entomopathogenic fungus Beauveria bassiana. In this investigation, two ferrous iron transporter-like proteins (Ftr) were functionally annotated in B.

Essential roles of ferric reductase-like proteins in growth, development, stress response, and virulence of the filamentous entomopathogenic fungus Beauveria bassiana.

In yeasts, ferric reductase catalyzes reduction of ferric ion to ferrous form, which is essential for the reductive iron assimilation system. However, the physiological roles of ferric reductases remain largely unknown in the filamentous fungi. In this study, genome-wide annotation revealed thirteen ferric reductase-like (Fre) proteins in the filamentous insect pathogenic fungus Beauveria bassiana, and all their functions were genetically characterized.

MARVEL family proteins contribute to vegetative growth, development, and virulence of the insect fungal pathogen Beauveria bassiana.

Beauveria bassiana is one of the most extensively studied entomopathogenic fungi (EPF) and is widely used as a biocontrol agent against various insect pests. Proteins containing the MARVEL domain are conserved in eukaryotes, typically with four transmembrane structures. In this study, we identified the five MARVEL domain proteins in B.

High photoreactivation activities of Rad2 and Rad14 in recovering insecticidal Beauveria bassiana from solar UV damage.

Anti-ultraviolet (UV) roles of Rad2 and Rad14 depend on nucleotide excision repair (NER) of UV-induced DNA lesions in budding yeast but remain unexplored yet in filamentous fungi. Here, nucleus-specific Rad2 and Rad14 orthologs are shown to recover Beauveria bassiana, a main source of wide-spectrum mycoinsecticides, from solar UV damage through photorepair-depending photoreactivation. As a photorepair index, photoreactivation (germination) rates of lethal UVB dose-irradiated conidia via a 3- or 5-h light plus 9- or 7-h dark incubation at 25 °C were drastically reduced in the Δrad2 and Δrad14 mutants versus a wild-type strain.

Rad6, a ubiquitin conjugator required for insect-pathogenic lifestyle, UV damage repair, and genomic expression of Beauveria bassiana.

The E2 ubiquitin conjugator Rad6 is required for DNA damage bypass in budding yeast but remain functionally unknown in filamentous fungi. Here, we report pleiotropic effect of Rad6 ortholog in Beauveria bassiana, a wide-spectrum fungal insecticide. Global ubiquitination signal was greatly attenuated in the absence of rad6.

Rad2, Rad14 and Rad26 recover Metarhizium robertsii from solar UV damage through photoreactivation in vivo.

Rad2, Rad14 and Rad26 recover ultraviolet (UV) damage by nucleotide excision repair (NER) in budding yeast but their functions in filamentous fungi have not been elucidated. Here, we report mechanistically different anti-UV effects of nucleus-specific Rad2, Rad14 and Rad26 orthologs in Metarhizium robertsii, an insect-pathogenic fungus. The null mutants of rad2, rad14 and rad26 showed a decrease of ∼90% in conidial resistance to UVB irradiation.

Functional insights of three RING-finger peroxins in the life cycle of the insect pathogenic fungus Beauveria bassiana.

Peroxisomes play important roles in fungal physiological processes. The RING-finger complex consists of peroxins Pex2, Pex10, and Pex12 and is essential for recycling of receptors responsible for peroxisomal targeting of matrix proteins. In this study, these three peroxins were functionally characterized in the entomopathogenic fungus Beauveria bassiana (Bb).

Only one of three hydrophobins (Hyd1-3) contributes to conidial hydrophobicity and insect pathogenicity of Metarhizium robertsii.

Class I/II hydrophobins constitute a family of small amphiphilic proteins that mediate cell hydrophobicity and adhesion to host or substrata and have pleiotropic effects in filamentous fungi. Here we report that only class I Hyd1 is essential for conidial hydrophobicity and insect pathogenicity among three hydrophobins (Hyd1-3) characterized in Metarhizium robertsii, an insect-pathogenic fungus. Aerial conidiation levels of three Δhyd1 mutants were much more reduced in 5-day-old cultures than in 7-day-old cultures, which were wettable (hydrophilic), but restored to a wild-type level in 15-day-old cultures.

Phosphorylation modification orchestrates the functionalities of peroxin 14 in filamentous entomopathogenic fungus Beauveria bassiana.

Peroxin 14 (Pex14) is a component of the receptor-docking complex at peroxisomal membrane. However, its post translation modification remains largely unknown in filamentous fungi. In this study, we characterized two phosphorylation sites (S54 and T262) in Beauveria bassiana Pex14 (BbPex14).

Homologs of bacterial heat-labile enterotoxin subunit A contribute to development, stress response, and virulence in filamentous entomopathogenic fungus .

Introduction: Enterotoxigenic bacteria commonly excrete heat-labile enterotoxins (LT) as virulence factors that consist of one subunit A (LTA) and five B subunits (LTB). In fungi, there are a large number of genes encoding the homologs of LTA, but their biological roles remain largely unknown.

Methods: In this study, we identified 14 enterotoxin_A domain proteins in filamentous fungus in which five proteins were functionally characterized.

Divergent roles of Rad4 and Rad23 homologs in 's resistance to solar ultraviolet damage.

The anti-ultraviolet (UV) role of a Rad4-Rad23-Rad33 complex in budding yeast relies on nucleotide excision repair (NER), which is mechanistically distinct from photorepair of DNA lesions generated under solar UV irradiation but remains poorly known in filamentous fungi. Here, two nucleus-specific Rad4 paralogs (Rad4A and Rad4B) and nucleocytoplasmic shuttling Rad23 ortholog are functionally characterized by multiple analyses of their null mutants in , an entomopathogenic fungus lacking Rad33. Rad4A was proven to interact with Rad23 and contribute significantly more to conidial UVB resistance (90%) than Rad23 (65%).

Two aminopeptidase I homologs convergently contribute to pathobiology of fungal entomopathogen Beauveria bassiana via divergent physiology-dependent autophagy pathways for vacuolar targeting.

Introduction: In yeast, the cytoplasm-to-vacuole targeting (Cvt) pathway acts as a biosynthetic autophagy-related process, in which vacuolar targeting of hydrolase is mediated by the machineries involved in the selective autophagy. However, the mechanistic insights into vacuolar targeting of hydrolases through the selective autophagy pathway still remain enigmatic in filamentous fungi.

Objectives: Our study aims to investigate the mechanisms involved in vacuolar targeting of hydrolases in filamentous fungi.

Autophagy-Related Gene 4 Participates in the Asexual Development, Stress Response and Virulence of Filamentous Insect Pathogenic Fungus .

Autophagy is a conserved mechanism for the turnover of intracellular components. Among the 'core' autophagy-related genes (), the cysteine protease Atg4 plays an important role in the activation of Atg8 by exposing the glycine residue at its extreme carboxyl terminus. In the insect fungal pathogen , a yeast ortholog of Atg4 was identified and functionally analyzed.

Timing of Fungal Insecticide Application to Avoid Solar Ultraviolet Irradiation Enhances Field Control of Rice Planthoppers.

Thechemical control of rice planthoppers (RPH)is prohibited in annual rice-shrimp rotation paddy fields. Here, the fungal insecticides ZJU435 and CQ421 were tested for control of RPH populations dominated by in three field trials. During four-week field trials initiated from the harsh weather of high temperatures and strong sunlight, the rice crop at the stages from tillering to flowering was effectively protected by fungal sprays applied at 14-day intervals.

Transcriptomic investigation reveals a physiological mechanism for to survive under linoleic acid stress.

In integrated pest management program (IPM), the compatibility of mycoinsecticides with bioactive fungicides [e.g., unsaturated fatty acids (UFAs)] has attracted more and more attention; however, the mechanisms underlying fungal resistance to UFAs remain largely unknown.

Co-Regulatory Roles of WC1 and WC2 in Asexual Development and Photoreactivation of .

The white collar proteins WC1 and WC2 interact with each other to form a white collar complex acting as a well-known transcription regulator required for the operation of the circadian clock in , but their roles in insect-pathogenic fungal lifecycles remain poorly understood. Here, we report that WC1 and WC2 orthologs co-regulate the conidiation capacity and conidial resistance to solar ultraviolet-B (UVB) irradiation in , after their high activities in the photorepair of UVB-induced DNA damages were elucidated previously in the insect mycopathogen, which features non-rhythmic conidiation and high conidiation capacity. The conidial yield, UVB resistance, and photoreactivation rate of UVB-impaired conidia were greatly reduced in the null mutants of and compared to their control strains.

Essential Role of WetA, but No Role of VosA, in Asexual Development, Conidial Maturation and Insect Pathogenicity of Metarhizium .

Conidial maturation, which is crucial for conidial quality, is controlled by the asexual development activator WetA and the downstream, velvety protein VosA in Aspergillus. Their orthologs have proved functional in conidial quality control of Beauveria bassiana, as seen in Aspergillus, but are functionally unexplored, in Metarhizium , another hypocrealean insect pathogen. Here, WetA and VosA prove essential and nonessential for 's life cycle, respectively.