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Metarhizium robertsii

Daniel Cook, Bruno G G Donzelli, Rebecca Creamer, Deana L Baucom, Dale R Gardner, Juan Pan, Neil Moore, Jerzy W Jaromczyk, Christopher L Schardl
Swainsonine, a cytotoxic fungal alkaloid and a potential cancer therapy drug, is produced by the insect pathogen and plant symbiont, Metarhizium robertsii, the clover pathogen Slafractonia leguminicola, locoweed symbionts belonging to Alternaria sect. Undifilum, and a recently discovered morning glory symbiont belonging to order Chaetothyriales. Genome sequence analyses revealed that these fungi shared orthologous gene clusters, designated "SWN," which included a multifunctional swnK gene comprising predicted adenylylation and acyltransferase domains with their associated thiolation domains, a β-ketoacyl synthase domain, and two reductase domains...
April 4, 2017: G3: Genes—Genomes—Genetics
Paulina Siewiera, Sylwia Różalska, Przemysław Bernat
Dibutyltin (DBT) is an environmental pollutant characterized by immunotoxic, neurotoxic, and pro-oxidant properties. In this study, an attempt was made to enhance DBT elimination by the Metarhizium robertsii strain. We observed enhanced fungal growth in the bioreactor (pO2 ≥ 20%) compared to flask cultures (μ max increased from 0.061 to 0.086 h(-1)). Moreover, under aerated conditions, M. robertsii mycelium with "hairy" morphology biodegraded DBT (20 mg l(-1)) 10-fold faster in the bioreactor than in the flask cultures...
March 27, 2017: Environmental Science and Pollution Research International
Aili Fan, Wubin Mi, Zhiguo Liu, Guohong Zeng, Peng Zhang, Youcai Hu, Weiguo Fang, Wen-Bing Yin
Histone deacetylation normally decreases the gene expression in organisms. By genome-wide deletions of epigenetic regulators in entomopathogenic fungus Metarhizium robertsii, unexpected activations of orphan secondary metabolite genes have been found upon the disruption of a histone acetyltransferase (HAT) gene Hat1. This led to the characterization of 11 new natural products, including eight isocoumarin derivatives meromusides A-H and two nonribosomal peptides meromutides A and B. Therefore, disruption of HAT represents a new approach to mine chemical diversity from fungi...
April 7, 2017: Organic Letters
Yulong Wang, Tiantian Wang, Lintao Qiao, Jianyu Zhu, Jinrui Fan, Tingting Zhang, Zhang-Xun Wang, Wanzhen Li, Anhui Chen, Bo Huang
DNA methylation is an important epigenetic mark in mammals, plants, and fungi and depends on multiple genetic pathways involving de novo and maintenance DNA methyltransferases (DNMTases). Metarhizium robertsii, a model system for investigating insect-fungus interactions, has been used as an environmentally friendly alternative to chemical insecticides. However, little is known concerning the molecular basis for DNA methylation. Here, we report on the roles of two DNMTases (MrRID and MrDIM-2) by characterizing ΔMrRID, ΔMrDIM-2, and ΔRID/ΔDIM-2 mutants...
February 25, 2017: Applied Microbiology and Biotechnology
Wanzhen Li, Yulong Wang, Jianyu Zhu, Zhangxun Wang, Guiliang Tang, Bo Huang
Conidia and mycelia are two important developmental stages in the asexual life cycle of entomopathogenic fungus Metarhizium. Despite the crucial role that DNA methylation plays in many biological processes, its role in regulation of gene expression and development in fungi is not yet fully understood. We performed genome-wide analysis of DNA methylation patterns of an M. robertsii strain with single base pair resolution. Specifically, we examined for changes in methylation patterns between the conidia and mycelia stages...
March 2017: Fungal Biology
Huimin Meng, Zhangxun Wang, Yulong Wang, Hong Zhu, Bo Huang
RNA interference (RNAi) is a gene-silencing mechanism that plays an important role in gene regulation in a number of eukaryotic organisms. Two core components, Dicer and Argonaute, are central in the RNAi machinery. However, the physiological roles of Dicer and Argonaute in the entomopathogenic fungus Metarhizium robertsii have remained unclear. Here, the roles of genes encoding Dicer (M. robertsiidcl1 [Mrdcl1] and Mrdcl2) and Argonaute (Mrago1 and Mrago2) proteins in M. robertsii were investigated. The results showed that the Dicer-like protein MrDCL2 and Argonaute protein MrAGO1 are the major components of the RNAi process occurring in M...
April 1, 2017: Applied and Environmental Microbiology
Scott W Behie, Camila C Moreira, Irina Sementchoukova, Larissa Barelli, Paul M Zelisko, Michael J Bidochka
Metarhizium robertsii is a common soil fungus that occupies a specialized ecological niche as an endophyte and an insect pathogen. Previously, we showed that the endophytic capability and insect pathogenicity of Metarhizium are coupled to provide an active method of insect-derived nitrogen transfer to a host plant via fungal mycelia. We speculated that in exchange for this insect-derived nitrogen, the plant would provide photosynthate to the fungus. By using (13)CO2, we show the incorporation of (13)C into photosynthate and the subsequent translocation of (13)C into fungal-specific carbohydrates (trehalose and chitin) in the root/endophyte complex...
January 18, 2017: Nature Communications
Vadim Y Kryukov, Olga N Yaroslavtseva, Miranda M A Whitten, Maksim V Tyurin, Katherine J Ficken, Carolyn Greig, Nadja R Melo, Viktor V Glupov, Ivan M Dubovskiy, Tariq M Butt
This study examines how the dynamics of fungus - insect interactions can be modulated by temperature. The wax moth, Galleria mellonella, is a well-studied and important model insect whose larvae in the wild develop optimally at around 34°C in beehives. However, surprisingly little research on wax moths has been conducted at relevant temperatures. In this study, the entomopathogenic fungus Metarhizium robertsii inflicted rapid and substantial mortality on wax moth larvae maintained at a constant temperature of 24°C, but at 34°C a ten-fold higher dose was required to achieve an equivalent mortality...
November 29, 2016: Insect Science
Bruno Giuliano Garisto Donzelli, B Gillian Turgeon, Donna M Gibson, Stuart B Krasnoff
Based on genomic analysis, polyketide synthase (PKS) and nonribosomal peptide synthetase (NRPS) pathways account for biosynthesis of the majority of the secondary metabolites produced by the entomopathogenic fungus Metarhizium robertsii. To evaluate the contribution of these pathways to M. robertsii fitness and/or virulence, mutants deleted for mrpptA, the Sfp-type 4' phosphopantetheinyl transferase gene required for their activation were generated. ΔmrpptA strains were deficient in PKS and NRPS activity resulting in colonies that lacked the typical green pigment and failed to produce the nonribosomal peptides (destruxins, serinocylins, and the siderophores ferricrocin and metachelins) as well as the hybrid polyketide-peptides (NG-39x) that are all produced by the wild type (WT) M...
November 19, 2016: Fungal Genetics and Biology: FG & B
Olga N Yaroslavtseva, Ivan M Dubovskiy, Viktor P Khodyrev, Bahytzhan A Duisembekov, Vadim Yu Kryukov, Viktor V Glupov
The synergistic effect between the entomopathogenic fungus Metarhizium robertsii and a sublethal dose of the bacterium Bacillus thuringiensis ssp. morrisoni var. tenebrionis was studied in terms of immune defense reactions and detoxification system activity of the Colorado potato beetle, Leptinotarsa decemlineata, fourth instar larvae. Bacterial infection led to more rapid germination of fungal conidia on integuments. We found a significant decrease of cellular immunity parameters, including total hemocyte count and encapsulation response, under the influence of bacteria...
January 2017: Journal of Insect Physiology
Oksana G Tomilova, Vadim Yu Kryukov, Bahytzhan A Duisembekov, Olga N Yaroslavtseva, Maksim V Tyurin, Natalia A Kryukova, Valery Skorokhod, Ivan M Dubovskiy, Viktor V Glupov
The interaction between the entomopathogenic fungus Metarhizium robertsii and natural avermectin metabolites of the actinomycete Streptomyces avermitilis were investigated on Colorado potato beetle larvae. A synergy in the mortality of larvae was detected after simultaneous treatment with half-lethal doses of avermectins (commercial name actarophit) 0.005% and fungus (5×10(5)conidia/ml). The treatment with avermectins led to rapid fungal colonization of the hemolymph. The defense strategies of insects infected by fungus and treated with avermectins and untreated insects were compared to investigate the mechanisms of this synergy...
October 2016: Journal of Invertebrate Pathology
Qiang Gao, Yuzhen Lu, Hongyan Yao, Yong-Jiang Xu, Wei Huang, Chengshu Wang
The final product of the glycerol phosphate (GP) pathway is triacylglycerol (TAG) that regulates the homeostasis of energy, fatty acids and phospholipids in cells. The enzymes involved in this pathway have been characterized in many model organisms; however, their contributions to fungal infection are largely unclear. In this study, we performed serial deletion of genes in the GP pathway in the insect pathogenic fungus Metarhizium robertsii. The results indicated that a lysophosphatidate acyltransferase mrLPAAT1 was required for fungal growth, cell differentiation, maintenance of cell polarity and virulence...
November 2016: Environmental Microbiology
Yamini Agrawal, Tarun Narwani, Srikrishna Subramanian
BACKGROUND: Aschersonia badia [(Ab) Teleomorph: Hypocrella siamensis] is an entomopathogenic fungus that specifically infects scale insects and whiteflies. We present the whole genome sequence of Ab and its comparison with two clavicipitaceous fungi Metarhizium robertsii (MR: generalist entomopathogen) and M. acridum (MAC: acridid-specific entomopathogen) that exhibit variable host preferences. Here, through comparative analysis of pathogen-host interacting genes, carbohydrate active enzymes, secondary metabolite biosynthesis genes, and sexuality genes, we explore the proteins with possible virulence functions in clavicipitaceous fungi...
2016: BMC Genomics
Hiroki Kato, Yuta Tsunematsu, Tsuyoshi Yamamoto, Takuya Namiki, Shinji Kishimoto, Hiroshi Noguchi, Kenji Watanabe
To rapidly identify novel natural products and their associated biosynthetic genes from underutilized and genetically difficult-to-manipulate microbes, we developed a method that uses (1) chemical screening to isolate novel microbial secondary metabolites, (2) bioinformatic analyses to identify a potential biosynthetic gene cluster and (3) heterologous expression of the genes in a convenient host to confirm the identity of the gene cluster and the proposed biosynthetic mechanism. The chemical screen was achieved by searching known natural product databases with data from liquid chromatographic and high-resolution mass spectrometric analyses collected on the extract from a target microbe culture...
July 2016: Journal of Antibiotics
Patricia Romans-Fuertes, Teis Esben Sondergaard, Manuela Ilse Helga Sandmann, Rasmus Dam Wollenberg, Kristian Fog Nielsen, Frederik T Hansen, Henriette Giese, Ditlev Egeskov Brodersen, Jens Laurids Sørensen
Sansalvamide is a cyclic pentadepsipeptide produced by Fusarium solani and has shown promising results as potential anti-cancer drug. The biosynthetic pathway has until now remained unidentified, but here we used an Agrobacterium tumefaciens-mediated transformation (ATMT) approach to generate knockout mutants of two candidate non-ribosomal peptide synthetases (NRPS29 and NRPS30). Comparative studies of secondary metabolites in the two deletion mutants and wild type confirmed the absence of sansalvamide in the NRPS30 deletion mutant, implicating this synthetase in the biosynthetic pathway for sansalvamide...
November 2016: Current Genetics
Guilherme T P Brancini, Drauzio E N Rangel, Gilberto Ú L Braga
Metarhizium acridum is an entomopathogenic fungus commonly used as a bioinsecticide. The conidium is the fungal stage normally employed as field inoculum in biological control programs and must survive under field conditions such as high ultraviolet-B (UV-B) exposure. Light, which is an important stimulus for many fungi, has been shown to induce the production of M. robertsii conidia with increased stress tolerance. Here we show that a two-hour exposure to white or blue/UV-A light of fast-growing mycelium induces tolerance to subsequent UV-B irradiation...
March 2016: FEMS Microbiology Letters
Xiaoxuan Chen, Chuan Xu, Ying Qian, Ran Liu, Qiangqiang Zhang, Guohong Zeng, Xin Zhang, Hong Zhao, Weiguo Fang
Metarhizium robertsii has been used as a model to study fungal pathogenesis in insects, and its pathogenicity has many parallels with plant and mammal pathogenic fungi. MAPK (Mitogen-activated protein kinase) cascades play pivotal roles in cellular regulation in fungi, but their functions have not been characterized in M. robertsii. In this study, we identified the full complement of MAPK cascade components in M. robertsii and dissected their regulatory roles in pathogenesis, conidiation and stress tolerance...
March 2016: Environmental Microbiology
Duangdao Wichadakul, Noppol Kobmoo, Supawadee Ingsriswang, Sithichoke Tangphatsornruang, Duriya Chantasingh, Janet Jennifer Luangsa-ard, Lily Eurwilaichitr
BACKGROUND: Ophiocordyceps unilateralis is an outstanding insect fungus for its biology to manipulate host ants' behavior and for its extreme host-specificity. Through the sequencing and annotation of Ophiocordyceps polyrhachis-furcata, a species in the O. unilateralis species complex specific to the ant Polyrhachis furcata, comparative analyses on genes involved in pathogenicity and virulence between this fungus and other fungi were undertaken in order to gain insights into its biology and the emergence of host specificity...
2015: BMC Genomics
Bernhardt M Steinwender, Jürg Enkerli, Franco Widmer, Jørgen Eilenberg, Hanne L Kristensen, Michael J Bidochka, Nicolai V Meyling
Metarhizium spp. have recently been shown to be associated with the roots of different plants. Here we evaluated which Metarhizium species were associated with roots of oat (Avena sativa), rye (Secale cereale) and cabbage (Brassica oleracea), common crop plants in Denmark. Thirty-six root samples from each of the three crops were collected within an area of approximately 3ha. The roots were rinsed with sterile water, homogenized and the homogenate plated onto selective media. A subset of 126 Metarhizium isolates were identified to species by sequencing of the 5' end of the gene translation elongation factor 1-alpha and characterized by simple sequence repeat (SSR) analysis of 14 different loci...
November 2015: Journal of Invertebrate Pathology
Johanna Mayerhofer, Andy Lutz, Franco Widmer, Stephen A Rehner, Adrian Leuchtmann, Jürg Enkerli
Cross-species transferability of 41 previously published simple sequence repeat (SSR) markers was assessed for 11 species of the entomopathogenic fungus Metarhizium. A collection of 65 Metarhizium strains including all 54 used in a recent phylogenetic revision of the genus were characterized. Between 15 and 34 polymorphic SSR markers produced scorable PCR amplicons in seven species, including M. anisopliae, M. brunneum, M. guizhouense, M. lepidiotae, M. majus, M. pingshaense, and M. robertsii. To provide genotyping tools for concurrent analysis of these seven species fifteen markers grouped in five multiplex pools were selected based on high allelic diversity and easy scorability of SSR chromatograms...
November 2015: Journal of Invertebrate Pathology
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