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Beauveria bassiana knockout

Yonghong Zhou, Nemat O Keyhani, Yongjun Zhang, Zhibing Luo, Yanhua Fan, Yujie Li, Qiaosheng Zhou, Jianjun Chen, Yan Pei
Cyclophilins are ubiquitous proteins found in all domains of life, catalyzing peptidyl-prolyl cis-trans isomerization (PPIase activity) and functioning in diverse cellular processes. The filamentous insect pathogenic fungus, Beauveria bassiana, contains 11 cyclophilin genes whose roles were probed via individual gene knockouts, construction of over-expression strains, and a simultaneous gene knockdown strategy using tandem SiRNA. Mutants were examined for effects on conidiation, hyphal growth, cyclosporine and stress resistance, and insect virulence...
November 2016: Environmental Microbiology
Shuaishuai Huang, Zhangjiang He, Shiwei Zhang, Nemat O Keyhani, Yulin Song, Zhi Yang, Yahui Jiang, Wenli Zhang, Yan Pei, Yongjun Zhang
The entomopathogenic fungus, Beauveria bassiana, is of environmental and economic importance as an insect pathogen, currently used for the biological control of a number of pests. Cell wall integrity and conidiation are critical parameters for the ability of the fungus to infect insects and for production of the infectious propagules. The contribution of calcineurin and the Slt2 MAP kinase to cell wall integrity and development in B. bassiana was investigated. Gene knockouts of either the calcineurin CNA1 subunit or the Slt2 MAP kinase resulted in decreased tolerance to calcofluor white and high temperature...
October 2015: Fungal Genetics and Biology: FG & B
Nicolás Pedrini, Almudena Ortiz-Urquiza, Carla Huarte-Bonnet, Yanhua Fan, M Patricia Juárez, Nemat O Keyhani
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...
July 14, 2015: Proceedings of the National Academy of Sciences of the United States of America
Yuqi Qin, Almudena Ortiz-Urquiza, Nemat O Keyhani
The filamentous fungus, Beauveria bassiana, is a ubiquitously distributed insect pathogen, currently used as an alternative to chemical pesticides for pest control. Conidiospores are the means by which the fungus disseminates in the environment, and these cells also represent the infectious agent most commonly used in field applications. Little, however, is known concerning the molecular basis for maintenance of spore viability, a critical feature for survival and persistence. Here, we report on the role of a putative methyltransferase, BbmtrA, in conidial viability, normal fungal growth and development, and virulence, via characterization of a targeted gene knockout strain...
November 2014: Microbiology
Zhibing Luo, Yujie Li, Jarrod Mousa, Steven Bruner, Yongjun Zhang, Yan Pei, Nemat O Keyhani
Fungal secondary metabolites are chemical compounds important for development, environmental adaptation and for potential biotechnological and pharmaceutical applications. Oosporein, a red-pigmented benzoquinone, produced by many fungal insect pathogenic Beauveria spp., shows remarkable functional diversity, displaying antimicrobial, antiviral and even anti-proliferative activities. A homologue of the msn2/seb1 transcription factor was identified in a Beauveria bassiana random T-DNA insertion library. Targeted gene-knockout of Bbmsn2 resulted in reduced growth and increased sensitivity to Calcofluor White, H2 O2 and Congo Red...
April 2015: Environmental Microbiology
Sheng-Hua Ying, Xiao-Ping Ji, Xiu-Xiu Wang, Ming-Guang Feng, Nemat O Keyhani
Multiprotein bridging factors (MBFs) are evolutionarily highly conserved cofactors that link TATA-binding protein and the associated basal transcription machinery to transcription factors. The filamentous fungus, Beauveria bassiana, has a multipotential lifestyle capable of growing as a saprophyte, plant endophyte and insect pathogen. Deletion of the single B. bassiana MBF homologue (BbMBF1) affected fungal growth and hyphal morphogenesis, stress response and virulence. Compared with wild type, the ΔBbMBF1 strain displayed increased sensitivity to UV-irradiation and to oxidative, osmotic and heat stress, and decreased virulence in both topical and intrahaemocoel injection bioassays using the greater wax moth, Galleria mellonella larvae...
June 2014: Environmental Microbiology
Xiu-Xiu Wang, Xiao-Ping Ji, Jing-Xin Li, Nemat O Keyhani, Ming-Guang Feng, Sheng-Hua Ying
Carbohydrate transporters are critical players mediating nutrient uptake during saprophytic and pathogenic growth for most filamentous fungi. For entomopathogenic fungi, such as Beauveria bassiana, assimilation of α-glucosides, in particular, trehalose, the major carbohydrate constituent of the insect haemolymph, has been hypothesized to represent an important ability for infectious growth within the insect hemocoel. In this study, a B. bassiana α-glucoside transporter homolog was identified and genetically characterized via generation of a targeted gene disruption mutant...
June 2013: Research in Microbiology
Nicolás Pedrini, Almudena Ortiz-Urquiza, Carla Huarte-Bonnet, Shizhu Zhang, Nemat O Keyhani
Broad host range entomopathogenic fungi such as Beauveria bassiana attack insect hosts via attachment to cuticular substrata and the production of enzymes for the degradation and penetration of insect cuticle. The outermost epicuticular layer consists of a complex mixture of non-polar lipids including hydrocarbons, fatty acids, and wax esters. Long chain hydrocarbons are major components of the outer waxy layer of diverse insect species, where they serve to protect against desiccation and microbial parasites, and as recognition molecules or as a platform for semiochemicals...
2013: Frontiers in Microbiology
Lei Zhang, Jie Wang, Xue-Qin Xie, Nemat O Keyhani, Ming-Guang Feng, Sheng-Hua Ying
Autophagy is a highly conserved process, representing the major eukaryotic degradative pathway of cellular components. Autophagy-mediated recycling of cellular materials contributes to cell differentiation, tissue remodelling and proper development. In fungi, autophagy is required for normal growth and cell differentiation. The entomopathogenic fungus Beauveria bassiana and its invertebrate targets represent a unique model system with which to examine host-pathogen interactions. The ATG5 gene is one of 17 involved in autophagosome formation, and the B...
February 2013: Microbiology
Sheng-Hua Ying, Ming-Guang Feng, Nemat O Keyhani
Genetic engineering offers a practical route for enhancing the insect biological control potential of entomopathogenic fungi such as Beauveria bassiana. To date, however, such efforts have relied upon transformation protocols that utilize antibiotic or herbicidal resistance markers as selection agents for the introduction of genes into the fungus. In order to avoid the use of such markers for the development of field-usable fungal strains, a markerless transformation system based upon complementation of uridine auxotrophy was developed...
April 2013: Applied Microbiology and Biotechnology
Zheng-Liang Wang, Long-Bin Zhang, Sheng-Hua Ying, Ming-Guang Feng
The catalase family of Beauveria bassiana (fungal entomopathogen) consists of catA (spore-specific), catB (secreted), catP (peroxisomal), catC (cytoplasmic) and catD (secreted peroxidase/catalase), which were distinguished in phylogeny and structure and functionally characterized by constructing single-gene disrupted and rescued mutants for enzymatic and multi-phenotypic analyses. Total catalase activity decreased 89% and 56% in ΔcatB and ΔcatP, corresponding to the losses of upper and lower active bands gel-profiled for all catalases respectively, but only 9-12% in other knockout mutants...
February 2013: Environmental Microbiology
Yanhua Fan, Almudena Ortiz-Urquiza, Ramsha A Kudia, Nemat O Keyhani
Neuronal calcium sensor proteins and their homologues participate in transducing extracellular signals that affect intracellular Ca(2+) levels, which in turn regulate enzyme activities, secretion, gene expression and other biological processes. The filamentous fungus Beauveria bassiana is a broad-host-range pathogen of insects that acidifies the extracellular milieu during growth and pathogenesis towards target hosts. A collection of B. bassiana random insertion mutants were screened on pH indicator plates and one mutant was isolated that displayed reduced acidification...
July 2012: Microbiology
Shizhu Zhang, Emilie Widemann, Grausem Bernard, Agnes Lesot, Franck Pinot, Nicolas Pedrini, Nemat O Keyhani
Infection of insects by the entomopathogenic fungus Beauveria bassiana proceeds via attachment and penetration of the host cuticle. The outermost epicuticular layer or waxy layer of the insect represents a structure rich in lipids including abundant amounts of hydrocarbons and fatty acids. A member of a novel cytochrome P450 subfamily, CYP52X1, implicated in fatty acid assimilation by B. bassiana was characterized. B. bassiana targeted gene knockouts lacking Bbcyp52x1 displayed reduced virulence when topically applied to Galleria mellonella, but no reduction in virulence was noted when the insect cuticle was bypassed using an intrahemoceol injection assay...
April 13, 2012: Journal of Biological Chemistry
Xue-Qin Xie, Fang Li, Sheng-Hua Ying, Ming-Guang Feng
The biocontrol potential of entomopathogenic fungi against arthropod pests depends on not only their virulence to target pests but tolerance to outdoor high temperature and solar UV irradiation. Two Beauveria bassiana superoxide dismutases (SODs), BbSod2 and BbSod3, were characterized as cytosolic and mitochondrial manganese-cored isoenzymes (MnSODs) dominating the total SOD activity of the fungal entomopathogen under normal growth conditions. To probe their effects on the biocontrol potential of B. bassiana, ΔBbSod2, ΔBbSod3, and three hairpin RNA-interfered (RNAi) mutants with the transcripts of both BbSod2 and BbSod3 being suppressed by 91-97% were constructed and assayed for various phenotypic parameters in conjunction with ΔBbSod2/BbSod2, ΔBbSod3/BbSod3 and wild-type (control strains)...
2012: PloS One
Zheng-Liang Wang, Jiang-dong Lu, Ming-Guang Feng
Knockout and complement mutants of mannitol-1-phosphate dehydrogenase (MPD) and mannitol dehydrogenase (MTD) were constructed to probe the roles of both enzymes in the mannitol metabolism and multi-stress tolerances of entomopathogenic fungus Beauveria bassiana. Compared with wild-type and complement mutants, ΔBbMPD lost 99.5% MPD activity for reducing fructose-6-phosphate to mannitol-1-phosphate while ΔBbMTD lost 78.9% MTD activity for oxidizing mannitol to fructose. Consequently, mannitol contents in mycelia and conidia decreased 68% and 83% for ΔBbMPD, and 16% and 38% for ΔBbMTD, accompanied by greatly enhanced trehalose accumulations due to 81-87% decrease in their neutral trehalase expression...
August 2012: Environmental Microbiology
Shizhu Zhang, Yu Xian Xia, Byong Kim, Nemat O Keyhani
The entomogenous filamentous fungus, Beauveria bassiana expresses two hydrophobin genes, hyd1 and hyd2, hypothesized to be involved in cell surface hydrophobicity, adhesion, virulence, and to constitute the protective spore coat structure known as the rodlet layer. Targeted gene inactivation of hyd1 resulted in seemingly 'bald' conidia that contained significantly altered surface fascicles or bundles. These cells displayed decreased spore hydrophobicity, loss of water mediated dispersal, changes in surface carbohydrate epitopes and β-1,3-glucan distribution, lowered virulence in insect bioassays, but no effect on adhesion...
May 2011: Molecular Microbiology
Shizhu Zhang, Yuxian Xia, Nemat O Keyhani
Beauveria bassiana is a mycoinsecticide alternative to chemicals for use in biological pest control. The fungus-insect interaction is also an emerging model system to examine unique aspects of the development, pathogenesis, and diversity of fungal lifestyles. The glycoside hydrolase 72 (GH72) family includes β-1,3-glucanosyltransferases that are glycosylphosphatidylinositol (GPI)-anchored cell wall-modeling enzymes affecting fungal physiology. A putative B. bassiana GPI-anchored β-1,3-glucanosyltransferase (Bbgas1) was isolated and characterized...
April 2011: Applied and Environmental Microbiology
Yongjun Zhang, Jianqing Zhang, Xiaodong Jiang, Guijiang Wang, Zhibing Luo, Yanhua Fan, Zengqiang Wu, Yan Pei
Beauveria bassiana is an important insect-pathogenic fungus that invades insects by direct penetration of the host cuticle. To delineate the molecular mechanisms involved in fungal infection, a mitogen-activated protein kinase (MAPK) gene, Bbmpk1, which encodes a YERK1 family MAPK was isolated and characterized. Targeted gene disruption of Bbmpk1 resulted in a complete loss of virulence when applied topically to host insects but did not affect growth of the fungus when conidia were injected directly into the hemocoel...
April 2010: Applied and Environmental Microbiology
Yongjun Zhang, Jianhua Zhao, Weiguo Fang, Jianqing Zhang, Zhibing Luo, Mi Zhang, Yanhua Fan, Yan Pei
Beauveria bassiana is an economically important insect-pathogenic fungus which is widely used as a biocontrol agent to control a variety of insect pests. However, its insecticide efficacy in the field is often influenced by adverse environmental factors. Thus, understanding the genetic regulatory processes involved in the response to environmental stress would facilitate engineering and production of a more efficient biocontrol agent. Here, a mitogen-activated protein kinase (MAPK)-encoding gene, Bbhog1, was isolated from B...
June 2009: Applied and Environmental Microbiology
Yuquan Xu, E M Kithsiri Wijeratne, Patricia Espinosa-Artiles, A A Leslie Gunatilaka, István Molnár
Fungal cyclooligomer depsipeptides such as beauvericin, bassianolide, and enniatins display antibiotic, antifungal, insecticidal, broad-spectrum cancer cell antiproliferative, and cell migration inhibitory activities. We have identified a gene encoding a novel enzyme, ketoisovalerate reductase (KIVR), which is the sole provider of D-hydroxyisovalerate (D-Hiv), a common precursor for cyclooligomer depsipeptide biosynthesis in Beauveria bassiana. KIVR and related hypothetical oxidoreductases encoded in fungal genomes are similar to ketopantoate reductases but not to D-hydroxycarboxylate dehydrogenases...
January 26, 2009: Chembiochem: a European Journal of Chemical Biology
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