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Rodríguez-Piña AL, Castaño de la Serna E, Jiménez-Bremont JF. The serine-arginine (SR) protein UmRrm75 from Ustilago maydis is a functional ortholog of yeast ScHrb1. Int Microbiol 2024; 27:819-830. [PMID: 37776379 DOI: 10.1007/s10123-023-00432-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 08/09/2023] [Accepted: 09/16/2023] [Indexed: 10/02/2023]
Abstract
The Basidiomycete fungus Ustilago maydis is a biotrophic pathogen of maize. The U. maydis UmRrm75 gene encodes an RNA-binding protein (RBP). In a previous study, we reported that ΔUmRrm75 null mutant strains accumulate H2O2, exhibit slow growth, and have decreased virulence in maize. Herein, we describe UmRrm75 as an ortholog of the ScHrb1, a serine-arginine (SR) protein identified in the yeast Saccharomyces cerevisiae, which plays a role in nuclear quality control, specifically in mRNA splicing and export processes. The yeast ScHrb1 mutant (ΔScHrb1) exhibits an increased sensitivity to elevated levels of boron. We noticed that the ΔScHrb1 displayed sensitivity to H2O2, which is consistent with previous findings in the ΔUmRrm75 mutant. We reversed the sensitivity phenotypes of boron and H2O2 by introducing the UmRrm75 gene into the ΔScHrb1 mutant. Furthermore, we generated complementary strains of U. maydis by expressing UmRrm75-GFP under its native promoter in the ∆UmRrm75 mutants. The UmRrm75-GFP/∆UmRrm75 complementary strains successfully recovered their growth capability under stressors, H2O2 and boron, resembling the parental strains FB2 and AB33. The subcellular localization experiments conducted in U. maydis revealed that the UmRrm75 protein is localized within the nucleus of both yeast and hyphae. The nuclear localization of the UmRrm75 protein remains unaltered even under conditions of heat or oxidative stress. This suggests that UmRrm75 might perform its RBP activity in the nucleus, as previously reported for ScHrb1. Our data contribute to understanding the role of the nuclear RBP UmRrm75 from the corn smut fungus U. maydis.
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Affiliation(s)
- Alma Laura Rodríguez-Piña
- Laboratorio de Biotecnología Molecular Plantas, División de Biología Molecular, Instituto Potosino de Investigación Científica y Tecnológica A.C., San Luis Potosi, San Luis Potosi, Mexico
- Unidad de Bioquímica y Biología Molecular de Plantas, Centro de Investigación Científica de Yucatán A.C., Merida, Yucatan, Mexico
| | - Enrique Castaño de la Serna
- Unidad de Bioquímica y Biología Molecular de Plantas, Centro de Investigación Científica de Yucatán A.C., Merida, Yucatan, Mexico
| | - Juan Francisco Jiménez-Bremont
- Laboratorio de Biotecnología Molecular Plantas, División de Biología Molecular, Instituto Potosino de Investigación Científica y Tecnológica A.C., San Luis Potosi, San Luis Potosi, Mexico.
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Song X, Chen M, Zhao Y, Zhang M, Zhang L, Zhang D, Song C, Shang X, Tan Q. Multi-stage nuclear transcriptomic insights of morphogenesis and biparental role changes in Lentinula edodes. Appl Microbiol Biotechnol 2023:10.1007/s00253-023-12624-y. [PMID: 37439832 DOI: 10.1007/s00253-023-12624-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Revised: 05/24/2023] [Accepted: 05/26/2023] [Indexed: 07/14/2023]
Abstract
Based on six offspring with different mitochondrial (M) and parental nuclear (N) genotypes, the multi-stage morphological characteristics and nuclear transcriptomes of Lentinula edodes were compared to investigate morphogenesis mechanisms during cultivation, the key reason for cultivar resistance to genotype changes, and regulation related to biparental role changes. Six offspring had specific transcriptomic data and morphological characteristics that were mainly regulated by the two parental nuclei, followed by the cytoplasm, at different growth stages. Importing a wild N genotype easily leads to failure or instability of fruiting; however, importing wild M genotypes may improve cultivars. Major facilitator superfamily (MFS) transporter genes encoding specific metabolites in spawns may play crucial roles in fruiting body formation. Pellets from submerged cultivation and spawns from sawdust substrate cultivation showed different carbon metabolic pathways, especially in secondary metabolism, degradation of lignin, cellulose and hemicellulose, and plasma membrane transport (mainly MFS). When the stage of small young pileus (SYP) was formed on the surface of the bag, the spawns inside were mainly involved in nutrient accumulation. Just broken pileus (JBP) showed a different expression of plasma membrane transporter genes related to intracellular material transport compared to SYP and showed different ribosomal proteins and cytochrome P450 functioning in protein biosynthesis and metabolism than near spreading pileus (NSP). Biparental roles mainly regulate offspring metabolism, growth, and morphogenesis by differentially expressing specific genes during different vegetative growth stages. Additionally, some genes encoding glycine-rich RNA-binding proteins, F-box, and folliculin-interacting protein repeat-containing proteins may be related to multi-stage morphogenesis. KEY POINTS: • Replacement of nuclear genotype is not suitable for cultivar breeding of L. edodes. • Some genes show a biparental role-divergent expression at mycelial growth stage. • Transcriptomic changes of some sawdust substrate cultivation stages have been elucidated.
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Affiliation(s)
- Xiaoxia Song
- Institute of Edible Fungi, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, People's Republic of China
| | - Mingjie Chen
- Institute of Edible Fungi, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, People's Republic of China
| | - Yan Zhao
- Institute of Edible Fungi, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, People's Republic of China
| | - Meiyan Zhang
- Institute of Edible Fungi, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, People's Republic of China
| | - Lujun Zhang
- Institute of Edible Fungi, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, People's Republic of China
| | - Dang Zhang
- Institute of Edible Fungi, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, People's Republic of China
| | - Chunyan Song
- Institute of Edible Fungi, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, People's Republic of China.
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
| | - Xiaodong Shang
- Institute of Edible Fungi, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, People's Republic of China
| | - Qi Tan
- Institute of Edible Fungi, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, People's Republic of China
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Soberanes-Gutiérrez CV, Castillo-Jiménez A, Pérez-Rueda E, Galán-Vásquez E. Construction and analysis of gene co-expression network in the pathogenic fungus Ustilago maydis. Front Microbiol 2022; 13:1048694. [PMID: 36569046 PMCID: PMC9767968 DOI: 10.3389/fmicb.2022.1048694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 11/21/2022] [Indexed: 12/12/2022] Open
Abstract
Introduction Biological systems respond to environmental disturbances and a wide range of compounds through complex gene interaction networks. The enormous growth of experimental information obtained using large-scale genomic techniques such as microarrays and RNA sequencing led to the construction of a wide variety of gene co-expression networks in recent years. These networks allow the discovery of clusters of co-expressed genes that potentially work in the same process linking them to biological processes often of interest to industrial, medicinal, and academic research. Methods In this study, we built the gene co-expression network of Ustilago maydis from the gene expression data of 168 samples belonging to 19 series, which correspond to the GPL3681 platform deposited in the NCBI using WGCNA software. This network was analyzed to identify clusters of co-expressed genes, gene hubs and Gene Ontology terms. Additionally, we identified relevant modules through a hypergeometric approach based on a predicted set of transcription factors and virulence genes. Results and Discussion We identified 13 modules in the gene co-expression network of U. maydis. The TFs enriched in the modules of interest belong to the superfamilies of Nucleic acid-binding proteins, Winged helix DNA-binding, and Zn2/Cys6 DNA-binding. On the other hand, the modules enriched with virulence genes were classified into diseases related to corn smut, Invasive candidiasis, among others. Finally, a large number of hypothetical, a large number of hypothetical genes were identified as highly co-expressed with virulence genes, making them possible experimental targets.
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Affiliation(s)
- Cinthia V. Soberanes-Gutiérrez
- Laboratorio de Ciencias Agrogenómicas, de la Escuela Nacional de Estudios Superiores Unidad León, Universidad Nacional Autónoma de México, León, Guanajuato, Mexico
| | - Alfredo Castillo-Jiménez
- Licenciatura en Biología, Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City, Mexico
| | - Ernesto Pérez-Rueda
- Unidad Académica Yucatán, Instituto de Investigaciones en Matemáticas Aplicadas y en Sistemas, Universidad Nacional Autónoma de México, Mérida, Mexico
| | - Edgardo Galán-Vásquez
- Departamento de Ingeniería de Sistemas Computacionales y Automatización, Instituto de Investigación en Matemáticas Aplicadas y en Sistemas. Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City, Mexico,*Correspondence: Edgardo Galán-Vásquez,
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Louet C, Blot C, Shelest E, Guerillot P, Zannini F, Pétrowski J, Frey P, Duplessis S. Annotation survey and life-cycle transcriptomics of transcription factors in rust fungi (Pucciniales) identify a possible role for cold shock proteins in dormancy exit. Fungal Genet Biol 2022; 161:103698. [PMID: 35483517 DOI: 10.1016/j.fgb.2022.103698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 03/03/2022] [Accepted: 04/19/2022] [Indexed: 11/16/2022]
Abstract
Fungi of the order Pucciniales are obligate plant biotrophs causing rust diseases. They exhibit a complex life cycle with the production of up to five spore types, infection of two unrelated hosts and an overwintering stage. Transcription factors (TFs) are key regulators of gene expression in eukaryote cells. In order to better understand genetic programs expressed during major transitions of the rust life cycle, we surveyed the complement of TFs in fungal genomes with an emphasis on Pucciniales. We found that despite their large gene numbers, rust genomes have a reduced repertoire of TFs compared to other fungi. The proportions of C2H2 and Zinc cluster -two of the most represented TF families in fungi- indicate differences in their evolutionary relationships in Pucciniales and other fungal taxa. The regulatory gene family encoding cold shock protein (CSP) showed a striking expansion in Pucciniomycotina with specific duplications in the order Pucciniales. The survey of expression profiles collected by transcriptomics along the life cycle of the poplar rust fungus revealed TF genes related to major biological transitions, e.g. response to environmental cues and host infection. Particularly, poplar rust CSPs were strongly expressed in basidia produced after the overwintering stage suggesting a possible role in dormancy exit. Expression during transition from dormant telia to basidia confirmed the specific expression of the three poplar rust CSP genes. Their heterologous expression in yeast improved cell growth after cold stress exposure, suggesting a probable regulatory function when the poplar rust fungus exits dormancy. This study addresses for the first time TF and regulatory genes involved in developmental transition in the rust life cycle opening perspectives to further explore molecular regulation in the biology of the Pucciniales.
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Affiliation(s)
| | - Carla Blot
- Université de Lorraine, INRAE, IAM, F-54000 Nancy, France
| | - Ekaterina Shelest
- School of biological Sciences, University of Portsmouth, King Henry 1 Street, PO1 D2Y, Portsmouth, United Kingdom
| | | | | | | | - Pascal Frey
- Université de Lorraine, INRAE, IAM, F-54000 Nancy, France
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St Leger RJ. Insects and their pathogens in a changing climate. J Invertebr Pathol 2021; 184:107644. [PMID: 34237297 DOI: 10.1016/j.jip.2021.107644] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 01/02/2021] [Accepted: 06/28/2021] [Indexed: 11/19/2022]
Abstract
The complex nature of climate change-mediated multitrophic interaction is an underexplored area, but has the potential to dramatically shift transmission and distribution of many insects and their pathogens, placing some populations closer to the brink of extinction. However, for individual insect-pathogen interactions climate change will have complicated hard-to-anticipate impacts. Thus, both pathogen virulence and insect host immunity are intrinsically linked with generalized stress responses, and in both pathogen and host have extensive trade-offs with nutrition (e.g., host plant quality), growth and reproduction. Potentially alleviating or exasperating these impacts, some pathogens and hosts respond genetically and rapidly to environmental shifts. This review identifies many areas for future research including a particular need to identify how altered global warming interacts with other environmental changes and stressors, and how consistent these impacts are across pathogens and hosts. With that achieved we would be closer to producing an overarching framework to integrate knowledge on all environmental interplay and infectious disease events.
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Affiliation(s)
- Raymond J St Leger
- Department of Entomology, University of Maryland, College Park, MD 20742, USA.
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St. Leger RJ, Wang JB. Metarhizium: jack of all trades, master of many. Open Biol 2020; 10:200307. [PMID: 33292103 PMCID: PMC7776561 DOI: 10.1098/rsob.200307] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 11/09/2020] [Indexed: 02/06/2023] Open
Abstract
The genus Metarhizium and Pochonia chlamydosporia comprise a monophyletic clade of highly abundant globally distributed fungi that can transition between long-term beneficial associations with plants to transitory pathogenic associations with frequently encountered protozoans, nematodes or insects. Some very common 'specialist generalist' species are adapted to particular soil and plant ecologies, but can overpower a wide spectrum of insects with numerous enzymes and toxins that result from extensive gene duplications made possible by loss of meiosis and associated genome defence mechanisms. These species use parasexuality instead of sex to combine beneficial mutations from separate clonal individuals into one genome (Vicar of Bray dynamics). More weakly endophytic species which kill a narrow range of insects retain sexuality to facilitate host-pathogen coevolution (Red Queen dynamics). Metarhizium species can fit into numerous environments because they are very flexible at the genetic, physiological and ecological levels, providing tractable models to address how new mechanisms for econutritional heterogeneity, host switching and virulence are acquired and relate to diverse sexual life histories and speciation. Many new molecules and functions have been discovered that underpin Metarhizium associations, and have furthered our understanding of the crucial ecology of these fungi in multiple habitats.
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Zhang J, Cui W, Abdul Haseeb H, Guo W. VdNop12, containing two tandem RNA recognition motif domains, is a crucial factor for pathogenicity and cold adaption in Verticillium dahliae. Environ Microbiol 2020; 22:5387-5401. [PMID: 33000558 DOI: 10.1111/1462-2920.15268] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 09/15/2020] [Accepted: 09/28/2020] [Indexed: 12/27/2022]
Abstract
Previous studies have reported the ability of fungi to overwinter in soil or on crop debris under different environmental conditions, but how fungi adapt to chilling is still largely unknown. In this study, we have identified and characterized the RNA binding protein (RBP) (VdNop12) by screening an Agrobacterium tumefaciens-mediated transformation-mediated insertional mutational library of Verticillium dahliae. We determined that this protein was essential to the pathogen for virulence on cotton plants. VdNop12 contains two tandem RNA recognition motif domains, and its orthologs are widely distributed in filamentous fungi. Mutants produced by disruption of VdNop12 showed defects in vegetative growth, conidiation and cell wall integrity. The mutant also showed an increase in sensitivity to low temperature, as compared to the wildtype and complementation strains. Yeast complementation assay showed that VdNop12 could functionally restore the growth phenotype of ΔScNop12 mutant of Saccharomyces cerevisiae at 15°C. We demonstrated that the VdNop12 is localized in the nucleus, and its loss resulted in the downregulated expression of several genes related to cAMP-PKA and MAPK pathways in V. dahliae. Our results demonstrated a crucial role of RBPs in the regulation of morphology, cold adaption, and pathogenic development in V. dahliae.
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Affiliation(s)
- Jun Zhang
- Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Weiye Cui
- Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Hafiz Abdul Haseeb
- Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Wei Guo
- Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
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Masoudi A, Wang M, Zhang X, Wang C, Qiu Z, Wang W, Wang H, Liu J. Meta-Analysis and Evaluation by Insect-Mediated Baiting Reveal Different Patterns of Hypocrealean Entomopathogenic Fungi in the Soils From Two Regions of China. Front Microbiol 2020; 11:1133. [PMID: 32595616 PMCID: PMC7303310 DOI: 10.3389/fmicb.2020.01133] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 05/05/2020] [Indexed: 01/16/2023] Open
Abstract
A survey was carried out on forest soils and grassland soils from Hebei and Sichuan provinces using Tenebrio molitor larvae as a bait, and high-throughput DNA sequencing (HTS) of the fungal internal transcribed spacer-2 ribosomal DNA was used to monitor the natural distribution of three leading hypocrealean families of insect fungal pathogens (Clavicipitaceae, Cordycipitaceae, and Ophiocordycipitaceae). The occurrence of insect fungal pathogens in soil samples from 98 different sites was compared. The use of insect bait indicated that entomopathogenic fungi of the genus Metarhizium were predominant, followed by Beauveria and Isaria. Molecular characterization using the Mz_FG543 intergenic region revealed that the Metarhizium species pool was phylogenetically composed of three closely related species as follows; Metarhizium pingshaense (n = 74), Metarhizium robertsii (n = 51), and Metarhizium brunneum (n = 26), as well as one isolate which clustered with Metarhizium flavoviride. Nine potentially new phylogenetic species were delimited within the M. flavoviride species complex by sequencing of the 5′ elongation factor-1 alpha region locus. The Beauveria (n = 64) and Isaria (n = 5) isolates were characterized via sequence analyses of the Bloc region. An intergenic spacer phylogeny of the Beauveria isolate assemblage revealed the phylogenetic species within the Beauveria bassiana clade. Interestingly, the individuals of M. pingshaense (n = 18) and M. brunneum (n = 12) exhibited the presence of both mating types in Sichuan Province. Similarly, for the Beauveria isolates, reproductive mode assays demonstrated that all four B. bassiana subclades possessed bipolar outcrossing mating systems. Of these, 19 isolates contained two mating types, and the rest were fixed for single mating types, revealing opportunities for intra-lineage heterothallic mating. The HTS results showed a significantly higher occurrence of the Clavicipitaceae family and the Metarhizium genus in the soil samples. The Venn diagram showed Metarhizium anisopliae (senso lato), Isaria farinose, and B. bassiana as frequently abundant fungal pathogen operational taxonomic units (core) across sampling sites, while the baiting method showed that the genus of Isaria was isolated locally. The Mantel test verified that community dissimilarity increased significantly with geographical distance, suggesting that geographical coordinates are possible factors that influence the insect fungal pathogen community composition in the studied sites. This study is the first to highlight the usefulness of utilizing soil baiting and deep sequencing to investigate the population dynamics of entomopathogens in soil.
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Affiliation(s)
- Abolfazl Masoudi
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Min Wang
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Xiaoli Zhang
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Can Wang
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Zhaoxi Qiu
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Wenying Wang
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Hui Wang
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Jingze Liu
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, China
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Rodriguez L, Voorhies M, Gilmore S, Beyhan S, Myint A, Sil A. Opposing signaling pathways regulate morphology in response to temperature in the fungal pathogen Histoplasma capsulatum. PLoS Biol 2019; 17:e3000168. [PMID: 31568523 PMCID: PMC6786654 DOI: 10.1371/journal.pbio.3000168] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 10/10/2019] [Accepted: 09/04/2019] [Indexed: 12/24/2022] Open
Abstract
Phenotypic switching between 2 opposing cellular states is a fundamental aspect of biology, and fungi provide facile systems to analyze the interactions between regulons that control this type of switch. A long-standing mystery in fungal pathogens of humans is how thermally dimorphic fungi switch their developmental form in response to temperature. These fungi, including the subject of this study, Histoplasma capsulatum, are temperature-responsive organisms that utilize unknown regulatory pathways to couple their cell shape and associated attributes to the temperature of their environment. H. capsulatum grows as a multicellular hypha in the soil that switches to a pathogenic yeast form in response to the temperature of a mammalian host. These states can be triggered in the laboratory simply by growing the fungus either at room temperature (RT; which promotes hyphal growth) or at 37 °C (which promotes yeast-phase growth). Prior worked revealed that 15% to 20% of transcripts are differentially expressed in response to temperature, but it is unclear which transcripts are linked to specific phenotypic changes, such as cell morphology or virulence. To elucidate temperature-responsive regulons, we previously identified 4 transcription factors (required for yeast-phase growth [Ryp]1-4) that are required for yeast-phase growth at 37 °C; in each ryp mutant, the fungus grows constitutively as hyphae regardless of temperature, and the cells fail to express genes that are normally induced in response to growth at 37 °C. Here, we perform the first genetic screen to identify genes required for hyphal growth of H. capsulatum at RT and find that disruption of the signaling mucin MSB2 results in a yeast-locked phenotype. RNA sequencing (RNAseq) experiments reveal that MSB2 is not required for the majority of gene expression changes that occur when cells are shifted to RT. However, a small subset of temperature-responsive genes is dependent on MSB2 for its expression, thereby implicating these genes in the process of filamentation. Disruption or knockdown of an Msb2-dependent mitogen-activated protein (MAP) kinase (HOG2) and an APSES transcription factor (STU1) prevents hyphal growth at RT, validating that the Msb2 regulon contains genes that control filamentation. Notably, the Msb2 regulon shows conserved hyphal-specific expression in other dimorphic fungi, suggesting that this work defines a small set of genes that are likely to be conserved regulators and effectors of filamentation in multiple fungi. In contrast, a few yeast-specific transcripts, including virulence factors that are normally expressed only at 37 °C, are inappropriately expressed at RT in the msb2 mutant, suggesting that expression of these genes is coupled to growth in the yeast form rather than to temperature. Finally, we find that the yeast-promoting transcription factor Ryp3 associates with the MSB2 promoter and inhibits MSB2 transcript expression at 37 °C, whereas Msb2 inhibits accumulation of Ryp transcripts and proteins at RT. These findings indicate that the Ryp and Msb2 circuits antagonize each other in a temperature-dependent manner, thereby allowing temperature to govern cell shape and gene expression in this ubiquitous fungal pathogen of humans.
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Affiliation(s)
- Lauren Rodriguez
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Mark Voorhies
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Sarah Gilmore
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Sinem Beyhan
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Anthony Myint
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Anita Sil
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
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Lovett B, Bilgo E, Diabate A, St Leger R. A review of progress toward field application of transgenic mosquitocidal entomopathogenic fungi. PEST MANAGEMENT SCIENCE 2019; 75:2316-2324. [PMID: 30801913 DOI: 10.1002/ps.5385] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 02/02/2019] [Accepted: 02/18/2019] [Indexed: 06/09/2023]
Abstract
In Africa, adult mosquito populations are primarily controlled with insecticide-impregnated bed nets and residual insecticide sprays. This coupled with widespread applications of pesticides in agriculture has led to increasing insecticide resistance in mosquito populations. We have developed multiple alternative strategies for exploiting transgenic Metarhizium spp. directed at: (i) shortening the lifespan of adult mosquitoes; (ii) reducing transmission potential of Plasmodium spp.; (iii) reducing vector competence via pre-lethal effects. The present challenge is to convert this promising strategy into a validated public health intervention by resolving outstanding issues related to the release of genetically modified organisms. © 2019 Society of Chemical Industry.
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Affiliation(s)
- Brian Lovett
- Department of Entomology, University of Maryland, College Park, MD, USA
| | - Etienne Bilgo
- Institut de Recherche en Sciences de la Santé/Centre Muraz, Bobo-Dioulasso, Burkina Faso
| | - Abdoulaye Diabate
- Institut de Recherche en Sciences de la Santé/Centre Muraz, Bobo-Dioulasso, Burkina Faso
| | - Raymond St Leger
- Department of Entomology, University of Maryland, College Park, MD, USA
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St Leger R, Diabate A, Lovett B. Regulate GM fungi to protect ecosystems-Response. Science 2019; 365:455. [PMID: 31371605 DOI: 10.1126/science.aay5221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Raymond St Leger
- Department of Entomology, University of Maryland, College Park, MD 20742, USA.
| | - Abdoulaye Diabate
- Institut de Recherche en Sciences de la Santé/Centre Muraz, Bobo-Dioulasso, Burkina Faso.
| | - Brian Lovett
- Department of Entomology, University of Maryland, College Park, MD 20742, USA
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The Ustilago maydis null mutant strains of the RNA-binding protein UmRrm75 accumulate hydrogen peroxide and melanin. Sci Rep 2019; 9:10813. [PMID: 31346214 PMCID: PMC6658566 DOI: 10.1038/s41598-019-47133-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 05/09/2019] [Indexed: 01/24/2023] Open
Abstract
Ustilago maydis is a dimorphic fungus that has emerged as a model organism for the study of fungal phytopathogenicity and RNA biology. In a previous study, we isolated the U. maydis UmRrm75 gene. The deletion of the UmRrm75 gene affected morphogenesis and pathogenicity. UmRrm75 gene encodes a protein containing three RNA recognition motifs. Here we determined that UmRrm75 has chaperone activity in Escherichia coli using the transcription anti-termination assay. Subsequently, we analyzed the growth of ΔUmRrm75 mutants at 15 °C and 37 °C, observing that mutant strains had reduced growth in comparison to parental strains. UmRrm75 gene expression was induced under these non-optimal temperatures. ΔUmRrm75 mutant colonies displayed a dark-brown color at 28 °C, which was confirmed to be melanin based on spectroscopic analysis and spectrometric data. Furthermore, ΔUmRrm75 mutant strains showed the presence of peroxisomes, and increased H2O2 levels, even at 28 °C. The ΔUmRrm75 mutant strains displayed a higher expression of redox-sensor UmYap1 gene and increased catalase activity than the parental strains. Our data show that deletion of the UmRrm75 gene results in higher levels of H2O2, increased melanin content, and abiotic stress sensitivity.
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Zeng G, Zhang P, Zhang Q, Zhao H, Li Z, Zhang X, Wang C, Yin WB, Fang W. Duplication of a Pks gene cluster and subsequent functional diversification facilitate environmental adaptation in Metarhizium species. PLoS Genet 2018; 14:e1007472. [PMID: 29958281 PMCID: PMC6042797 DOI: 10.1371/journal.pgen.1007472] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 07/12/2018] [Accepted: 06/06/2018] [Indexed: 12/15/2022] Open
Abstract
The ecological importance of the duplication and diversification of gene clusters that synthesize secondary metabolites in fungi remains poorly understood. Here, we demonstrated that the duplication and subsequent diversification of a gene cluster produced two polyketide synthase gene clusters in the cosmopolitan fungal genus Metarhizium. Diversification occurred in the promoter regions and the exon-intron structures of the two Pks paralogs (Pks1 and Pks2). These two Pks genes have distinct expression patterns, with Pks1 highly expressed during conidiation and Pks2 highly expressed during infection. Different upstream signaling pathways were found to regulate the two Pks genes. Pks1 is positively regulated by Hog1-MAPK, Slt2-MAPK and Mr-OPY2, while Pks2 is positively regulated by Fus3-MAPK and negatively regulated by Mr-OPY2. Pks1 and Pks2 have been subjected to positive selection and synthesize different secondary metabolites. PKS1 is involved in synthesis of an anthraquinone derivative, and contributes to conidial pigmentation, which plays an important role in fungal tolerance to UV radiation and extreme temperatures. Disruption of the Pks2 gene delayed formation of infectious structures and increased the time taken to kill insects, indicating that Pks2 contributes to pathogenesis. Thus, the duplication of a Pks gene cluster and its subsequent functional diversification has increased the adaptive flexibility of Metarhizium species.
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Affiliation(s)
- Guohong Zeng
- Institute of Microbiology, Zhejiang University, Hangzhou, China
| | - Peng Zhang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, People’s Republic of China
| | | | - Hong Zhao
- Institute of Microbiology, Zhejiang University, Hangzhou, China
| | - Zixin Li
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Xing Zhang
- Institute of Microbiology, Zhejiang University, Hangzhou, China
| | - Chengshu Wang
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Wen-Bing Yin
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Weiguo Fang
- Institute of Microbiology, Zhejiang University, Hangzhou, China
- * E-mail:
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14
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Cold Shock as a Screen for Genes Involved in Cold Acclimatization in Neurospora crassa. G3-GENES GENOMES GENETICS 2018; 8:1439-1454. [PMID: 29563189 PMCID: PMC5940138 DOI: 10.1534/g3.118.200112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
When subjected to rapid drops of temperature (cold shock), Neurospora responds with a temporary shift in its morphology. This report is the first to examine this response genetically. We report here the results of a screen of selected mutants from the Neurospora knockout library for alterations in their morphological response to cold shock. Three groups of knockouts were selected to be subject to this screen: genes previously suspected to be involved in hyphal development as well as knockouts resulting in morphological changes; transcription factors; and genes homologous to E. coli genes known to alter their expression in response to cold shock. A total of 344 knockout strains were subjected to cold shock. Of those, 118 strains were identified with altered responses. We report here the cold shock morphologies and GO categorizations of strains subjected to this screen. Of strains with knockouts in genes associated with hyphal growth or morphology, 33 of 131 tested (25%) showed an altered response to cold shock. Of strains with knockouts in transcription factor genes, 30 of 145 (20%) showed an altered response to cold shock. Of strains with knockouts in genes homologous to E. coli genes which display altered levels of transcription in response to cold shock, a total of 55 of 68 tested (81%) showed an altered cold shock response. This suggests that the response to cold shock in these two organisms is largely shared in common.
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15
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Lovett B, St Leger RJ. Genetically engineering better fungal biopesticides. PEST MANAGEMENT SCIENCE 2018; 74:781-789. [PMID: 28905488 DOI: 10.1002/ps.4734] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 09/08/2017] [Indexed: 06/07/2023]
Abstract
Microbial insect pathogens offer an alternative means of pest control with the potential to wean us off our heavy reliance on chemical pesticides. Insect pathogenic fungi play an important natural role in controlling disease vectors and agricultural pests. Most commercial products employ Ascomycetes in the genera Metarhizium and Beauveria. However, their utilization has been limited by inconsistent field results as a consequence of sensitivity to abiotic stresses and naturally low virulence. Other naturally occurring biocontrol agents also face these hurdles to successful application, but the availability of complete genomes and recombinant DNA technologies have facilitated design of multiple fungal pathogens with enhanced virulence and stress resistance. Many natural and synthetic genes have been inserted into entomopathogen genomes. Some of the biggest gains in virulence have been obtained using genes encoding neurotoxic peptides, peptides that manipulate host physiology and proteases and chitinases that degrade the insect cuticle. Prokaryotes, particularly extremophiles, are useful sources of genes for improving entomopathogen resistance to ultraviolet (UV) radiation. These biological insecticides are environmentally friendly and cost-effective insect pest control options. © 2017 Society of Chemical Industry.
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Affiliation(s)
- Brian Lovett
- Department of Entomology, University of Maryland, College Park, MD, USA
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16
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Kelly AC, Ward TJ. Population genomics of Fusarium graminearum reveals signatures of divergent evolution within a major cereal pathogen. PLoS One 2018; 13:e0194616. [PMID: 29584736 PMCID: PMC5870968 DOI: 10.1371/journal.pone.0194616] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 03/06/2018] [Indexed: 12/30/2022] Open
Abstract
The cereal pathogen Fusarium graminearum is the primary cause of Fusarium head blight (FHB) and a significant threat to food safety and crop production. To elucidate population structure and identify genomic targets of selection within major FHB pathogen populations in North America we sequenced the genomes of 60 diverse F. graminearum isolates. We also assembled the first pan-genome for F. graminearum to clarify population-level differences in gene content potentially contributing to pathogen diversity. Bayesian and phylogenomic analyses revealed genetic structure associated with isolates that produce the novel NX-2 mycotoxin, suggesting a North American population that has remained genetically distinct from other endemic and introduced cereal-infecting populations. Genome scans uncovered distinct signatures of selection within populations, focused in high diversity, frequently recombining regions. These patterns suggested selection for genomic divergence at the trichothecene toxin gene cluster and thirteen additional regions containing genes potentially involved in pathogen specialization. Gene content differences further distinguished populations, in that 121 genes showed population-specific patterns of conservation. Genes that differentiated populations had predicted functions related to pathogenesis, secondary metabolism and antagonistic interactions, though a subset had unique roles in temperature and light sensitivity. Our results indicated that F. graminearum populations are distinguished by dozens of genes with signatures of selection and an array of dispensable accessory genes, suggesting that FHB pathogen populations may be equipped with different traits to exploit the agroecosystem. These findings provide insights into the evolutionary processes and genomic features contributing to population divergence in plant pathogens, and highlight candidate genes for future functional studies of pathogen specialization across evolutionarily and ecologically diverse fungi.
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Affiliation(s)
- Amy C. Kelly
- United States Department of Agriculture, Agricultural Research Service, Peoria, Illinois, United States of America
| | - Todd J. Ward
- United States Department of Agriculture, Agricultural Research Service, Peoria, Illinois, United States of America
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17
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Zhang X, St. Leger RJ, Fang W. Stress-induced pyruvate accumulation contributes to cross protection in a fungus. Environ Microbiol 2018; 20:1158-1169. [DOI: 10.1111/1462-2920.14058] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 01/07/2018] [Accepted: 01/25/2018] [Indexed: 11/30/2022]
Affiliation(s)
- Xing Zhang
- Institute of Microbiology; Zhejiang University; Hangzhou People's Republic of China
| | | | - Weiguo Fang
- Institute of Microbiology; Zhejiang University; Hangzhou People's Republic of China
- Institute of Insect Sciences; Zhejiang University; Hangzhou People's Republic of China
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18
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Elevational distribution and morphological attributes of the entomopathogenic fungi from forests of the Qinling Mountains in China. Appl Microbiol Biotechnol 2017; 102:1483-1499. [DOI: 10.1007/s00253-017-8651-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 11/06/2017] [Accepted: 11/12/2017] [Indexed: 01/27/2023]
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19
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Alternative transcription start site selection in Mr-OPY2 controls lifestyle transitions in the fungus Metarhizium robertsii. Nat Commun 2017; 8:1565. [PMID: 29146899 PMCID: PMC5691130 DOI: 10.1038/s41467-017-01756-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 10/12/2017] [Indexed: 12/15/2022] Open
Abstract
Metarhizium robertsii is a versatile fungus with saprophytic, plant symbiotic and insect pathogenic lifestyle options. Here we show that M. robertsii mediates the saprophyte-to-insect pathogen transition through modulation of the expression of a membrane protein, Mr-OPY2. Abundant Mr-OPY2 protein initiates appressorium formation, a prerequisite for infection, whereas reduced production of Mr-OPY2 elicits saprophytic growth and conidiation. The precise regulation of Mr-OPY2 protein production is achieved via alternative transcription start sites. During saprophytic growth, a single long transcript is produced with small upstream open reading frames in its 5′ untranslated region. Increased production of Mr-OPY2 protein on host cuticle is achieved by expression of a transcript variant lacking a small upstream open reading frame that would otherwise inhibit translation of Mr-OPY2. RNA-seq and qRT-PCR analyses show that Mr-OPY2 is a negative regulator of a transcription factor that we demonstrate is necessary for appressorial formation. These findings provide insights into the mechanisms regulating fungal lifestyle transitions. The fungus Metarhizium robertsii can act as a saprophyte, plant symbiont and insect pathogen. Here, the authors show that the use of alternative transcription start sites controls the expression of membrane protein Mr-OPY2, which in turn modulates the saprophyte-to-pathogen transition.
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20
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Wang D, Li L, Wu G, Vasseur L, Yang G, Huang P. De novo transcriptome sequencing of Isaria cateniannulata and comparative analysis of gene expression in response to heat and cold stresses. PLoS One 2017; 12:e0186040. [PMID: 29023475 PMCID: PMC5638334 DOI: 10.1371/journal.pone.0186040] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 09/22/2017] [Indexed: 11/19/2022] Open
Abstract
Isaria cateniannulata is a very important and virulent entomopathogenic fungus that infects many insect pest species. Although I. cateniannulata is commonly exposed to extreme environmental temperature conditions, little is known about its molecular response mechanism to temperature stress. Here, we sequenced and de novo assembled the transcriptome of I. cateniannulata in response to high and low temperature stresses using Illumina RNA-Seq technology. Our assembly encompassed 17,514 unigenes (mean length = 1,197 bp), in which 11,445 unigenes (65.34%) showed significant similarities to known sequences in NCBI non-redundant protein sequences (Nr) database. Using digital gene expression analysis, 4,483 differentially expressed genes (DEGs) were identified after heat treatment, including 2,905 up-regulated genes and 1,578 down-regulated genes. Under cold stress, 1,927 DEGs were identified, including 1,245 up-regulated genes and 682 down-regulated genes. The expression patterns of 18 randomly selected candidate DEGs resulting from quantitative real-time PCR (qRT-PCR) were consistent with their transcriptome analysis results. Although DEGs were involved in many pathways, we focused on the genes that were involved in endocytosis: In heat stress, the pathway of clathrin-dependent endocytosis (CDE) was active; however at low temperature stresses, the pathway of clathrin-independent endocytosis (CIE) was active. Besides, four categories of DEGs acting as temperature sensors were observed, including cell-wall-major-components-metabolism-related (CWMCMR) genes, heat shock protein (Hsp) genes, intracellular-compatible-solutes-metabolism-related (ICSMR) genes and glutathione S-transferase (GST). These results enhance our understanding of the molecular mechanisms of I. cateniannulata in response to temperature stresses and provide a valuable resource for the future investigations.
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Affiliation(s)
- Dingfeng Wang
- Tea Research Institute, Fujian Academy of Agricultural Sciences, Fu’an, Fujian, China
| | - Liangde Li
- Tea Research Institute, Fujian Academy of Agricultural Sciences, Fu’an, Fujian, China
| | - Guangyuan Wu
- Tea Research Institute, Fujian Academy of Agricultural Sciences, Fu’an, Fujian, China
- * E-mail: (GYW); (GY)
| | - Liette Vasseur
- Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture, Fuzhou, Fujian, China
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- Department of Biological Sciences, Brock University, St Catharines, Ontario, Canada
| | - Guang Yang
- Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture, Fuzhou, Fujian, China
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- Key Laboratory of Green Control of Insect Pests (Fujian Agriculture and Forestry University), Fujian Province University, Fuzhou, Fujian, China
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- * E-mail: (GYW); (GY)
| | - Pengrong Huang
- Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture, Fuzhou, Fujian, China
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- Key Laboratory of Green Control of Insect Pests (Fujian Agriculture and Forestry University), Fujian Province University, Fuzhou, Fujian, China
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
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21
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Abstract
Heat tolerance is well known to be key to fungal survival in many habitats, but our mechanistic understanding of how organisms adapt to heat stress is still incomplete. Using Metarhizium robertsii, an emerging model organism for assessing evolutionary processes, we report that pyruvate is in the vanguard of molecules that scavenge heat-induced reactive oxygen species (ROS). We show that, as well as inducing a rapid burst of ROS production, heat stress also downregulates genes for pyruvate consumption. The accumulating pyruvate is the fastest acting of several M. robertsii ROS scavengers, efficiently reducing protein carbonylation, stabilizing mitochondrial membrane potential, and promoting fungal growth. The acetate produced from pyruvate-ROS reactions itself causes acid stress, tolerance to which is regulated by Hog1 mitogen-activated protein kinase. Heat stress also induces pyruvate accumulation in several other fungi, suggesting that scavenging of heat-induced ROS by pyruvate is widespread. Heat is a dangerous challenge for most organisms, as it denatures proteins and induces the production of ROS that inactivate proteins, lipid membranes, and DNA. How organisms respond to this stress is not fully understood. Using the experimentally tractable insect pathogen Metarhizium robertsii as a model organism, we show for the first time that heat stress induces pyruvate production and that this functions as the first line of defense against heat-induced ROS. Heat stress also induces rapid pyruvate accumulation in other fungi, suggesting that pyruvate is a common but unappreciated defense against stress.
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Abstract
Fungi are the most common disease-causing agents of insects; aside from playing a crucial role in natural ecosystems, insect-killing fungi are being used as alternatives to chemical insecticides and as resources for biotechnology and pharmaceuticals. Some common experimentally tractable genera, such as Metarhizium spp., exemplify genetic diversity and dispersal because they contain numerous intraspecific variants with distinct environmental and insect host ranges. The availability of tools for molecular genetics and multiple sequenced genomes has made these fungi ideal experimental models for answering basic questions on the genetic and genomic processes behind adaptive phenotypes. For example, comparative genomics of entomopathogenic fungi has shown they exhibit diverse reproductive modes that often determine rates and patterns of genome evolution and are linked as cause or effect with pathogenic strategies. Fungal-insect pathogens represent lifestyle adaptations that evolved numerous times, and there are significant differences in host range and pathogenic strategies between the major groups. However, typically, spores landing on the cuticle produce appressoria and infection pegs that breach the cuticle using mechanical pressure and cuticle-degrading enzymes. Once inside the insect body cavity, fungal pathogens face a potent and comprehensively studied immune defense by which the host attempts to eliminate or reduce an infection. The Fungal Kingdom stands alone in the range, extent, and complexity of their manipulation of arthropod behavior. In part, this is because most only sporulate on cadavers, so they must ensure the dying host positions itself to allow efficient transmission.
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23
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Wang JB, Lu HL, St. Leger RJ. The genetic basis for variation in resistance to infection in the Drosophila melanogaster genetic reference panel. PLoS Pathog 2017; 13:e1006260. [PMID: 28257468 PMCID: PMC5352145 DOI: 10.1371/journal.ppat.1006260] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 03/15/2017] [Accepted: 02/24/2017] [Indexed: 01/01/2023] Open
Abstract
Individuals vary extensively in the way they respond to disease but the genetic basis of this variation is not fully understood. We found substantial individual variation in resistance and tolerance to the fungal pathogen Metarhizium anisopliae Ma549 using the Drosophila melanogaster Genetic Reference Panel (DGRP). In addition, we found that host defense to Ma549 was correlated with defense to the bacterium Pseudomonas aeruginosa Pa14, and several previously published DGRP phenotypes including oxidative stress sensitivity, starvation stress resistance, hemolymph glucose levels, and sleep indices. We identified polymorphisms associated with differences between lines in both their mean survival times and microenvironmental plasticity, suggesting that lines differ in their ability to adapt to variable pathogen exposures. The majority of polymorphisms increasing resistance to Ma549 were sex biased, located in non-coding regions, had moderately large effect and were rare, suggesting that there is a general cost to defense. Nevertheless, host defense was not negatively correlated with overall longevity and fecundity. In contrast to Ma549, minor alleles were concentrated in the most Pa14-susceptible as well as the most Pa14-resistant lines. A pathway based analysis revealed a network of Pa14 and Ma549-resistance genes that are functionally connected through processes that encompass phagocytosis and engulfment, cell mobility, intermediary metabolism, protein phosphorylation, axon guidance, response to DNA damage, and drug metabolism. Functional testing with insertional mutagenesis lines indicates that 12/13 candidate genes tested influence susceptibility to Ma549. Many candidate genes have homologs identified in studies of human disease, suggesting that genes affecting variation in susceptibility are conserved across species.
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Affiliation(s)
- Jonathan B. Wang
- Department of Entomology, University of Maryland College Park, College Park, Maryland, United States of America
| | - Hsiao-Ling Lu
- Department of Entomology, University of Maryland College Park, College Park, Maryland, United States of America
| | - Raymond J. St. Leger
- Department of Entomology, University of Maryland College Park, College Park, Maryland, United States of America
- * E-mail:
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24
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Wang Y, Wang T, Qiao L, Zhu J, Fan J, Zhang T, Wang ZX, Li W, Chen A, Huang B. DNA methyltransferases contribute to the fungal development, stress tolerance and virulence of the entomopathogenic fungus Metarhizium robertsii. Appl Microbiol Biotechnol 2017; 101:4215-4226. [PMID: 28238081 DOI: 10.1007/s00253-017-8197-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 02/04/2017] [Accepted: 02/11/2017] [Indexed: 12/31/2022]
Abstract
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. The results showed that approximately 71, 10, and 8% of mC sites remained in the ΔMrRID, ΔMrDIM-2, and ΔRID/ΔDIM-2 strains, respectively, compared with the wild-type (WT) strain. Further analysis showed that MrRID regulates the specificity of DNA methylation and MrDIM-2 is responsible for most DNA methylation, implying an interaction or cooperation between MrRID and MrDIM-2 for DNA methylation. Moreover, the ΔMrDIM-2 and ΔRID/ΔDIM-2 strains showed more defects in radial growth and conidial production compared to the WT. Under ultraviolet (UV) irradiation or heat stress, an obvious reduction in spore viability was observed for all the mutant strains compared to the WT. The spore median lethal times (LT50s) for the ΔMrDIM-2 and ΔRID/ΔDIM-2 strains in the greater wax moth, Galleria mellonella, were decreased by 47.7 and 65.9%, respectively, which showed that MrDIM-2 is required for full fungal virulence. Our data advances the understanding of the function of DNMTase in entomopathogenic fungi, which should contribute to future epigenetic investigations in fungi.
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Affiliation(s)
- Yulong Wang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, 230036, China
| | - Tiantian Wang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, 230036, China
| | - Lintao Qiao
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, 230036, China
| | - Jianyu Zhu
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, 230036, China
| | - Jinrui Fan
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, 230036, China
| | - Tingting Zhang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, 230036, China
| | - Zhang-Xun Wang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, 230036, China.,School of Plant Protection, Anhui Agricultural University, Hefei, 230036, China
| | - Wanzhen Li
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, 230036, China.,Engineering Technology Research Center of Microbial Fermentation Anhui Province, Anhui Polytechnic University, Wuhu, 241000, China
| | - Anhui Chen
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, 230036, China.,Department of Food and Biology, Xuzhou Institute of Technology, Xuzhou, 221008, China
| | - Bo Huang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, 230036, China.
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25
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Baral B. Entomopathogenicity and Biological Attributes of Himalayan Treasured Fungus Ophiocordyceps sinensis (Yarsagumba). J Fungi (Basel) 2017; 3:E4. [PMID: 29371523 PMCID: PMC5715966 DOI: 10.3390/jof3010004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 01/20/2017] [Accepted: 01/31/2017] [Indexed: 01/01/2023] Open
Abstract
Members of the entomophagous fungi are considered very crucial in the fungal domain relative to their natural phenomenon and economic perspectives; however, inadequate knowledge of their mechanisms of interaction keeps them lagging behind in parallel studies of fungi associated with agro-ecology, forest pathology and medical biology. Ophiocordyceps sinensis (syn. Cordyceps sinensis), an intricate fungus-caterpillar complex after it parasitizes the larva of the moth, is a highly prized medicinal fungus known widely for ages due to its peculiar biochemical assets. Recent technological innovations have significantly contributed a great deal to profiling the variable clinical importance of this fungus and other related fungi with similar medicinal potential. However, a detailed mechanism behind fungal pathogenicity and fungal-insect interactions seems rather ambiguous and is poorly justified, demanding special attention. The goal of the present review is to divulge an update on the published data and provides promising insights on different biological events that have remained underemphasized in previous reviews on fungal biology with relation to life-history trade-offs, host specialization and selection pressures. The infection of larvae by a fungus is not a unique event in Cordyceps; hence, other fungal species are also reviewed for effective comparison. Conceivably, the rationale and approaches behind the inheritance of pharmacological abilities acquired and stored within the insect framework at a time when they are completely hijacked and consumed by fungal parasites, and the molecular mechanisms involved therein, are clearly documented.
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Affiliation(s)
- Bikash Baral
- Research, Community Development and Conservation Center (C3DR), Pokhara 33700, Nepal.
- Department of Biochemistry, University of Turku, Turku, Finn-20014, Finland.
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26
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Nguyen Van Long N, Vasseur V, Coroller L, Dantigny P, Le Panse S, Weill A, Mounier J, Rigalma K. Temperature, water activity and pH during conidia production affect the physiological state and germination time of Penicillium species. Int J Food Microbiol 2016; 241:151-160. [PMID: 27780083 DOI: 10.1016/j.ijfoodmicro.2016.10.022] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 09/28/2016] [Accepted: 10/17/2016] [Indexed: 11/25/2022]
Abstract
Conidial germination and mycelial growth are generally studied with conidia produced under optimal conditions to increase conidial yield. Nonetheless, the physiological state of such conidia most likely differs from those involved in spoilage of naturally contaminated food. The present study aimed at investigating the impact of temperature, pH and water activity (aw) during production of conidia on the germination parameters and compatible solutes of conidia of Penicillium roqueforti and Penicillium expansum. Low temperature (5°C) and reduced aw (0.900 aw) during sporulation significantly reduced conidial germination times whereas the pH of the sporulation medium only had a slight effect at the tested values (2.5, 8.0). Conidia of P. roqueforti produced at 5°C germinated up to 45h earlier than those produced at 20°C. Conidia of P. roqueforti and P. expansum produced at 0.900 aw germinated respectively up to 8h and 3h earlier than conidia produced at 0.980 aw. Furthermore, trehalose and mannitol assessments suggested that earlier germination might be related to delayed conidial maturation even though no ultra-structural modifications were observed by transmission electron microscopy. Taken together, these results highlight the importance of considering environmental conditions during sporulation in mycological studies. The physiological state of fungal conidia should be taken into account to design challenge tests or predictive mycology studies. This knowledge may also be of interest to improve the germination capacity of fungal cultures commonly used in fermented foods.
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Affiliation(s)
- Nicolas Nguyen Van Long
- Université de Brest, EA 3882, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, IBSAM, ESIAB, Technopôle Brest-Iroise, 29280 Plouzané, France
| | - Valérie Vasseur
- Université de Brest, EA 3882, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, IBSAM, ESIAB, Technopôle Brest-Iroise, 29280 Plouzané, France
| | - Louis Coroller
- Université de Brest, EA 3882, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, IBSAM, UMT Spore Risk, IUT Quimper, 6 rue de l'Université, 29334 Quimper, France
| | - Philippe Dantigny
- Université de Brest, EA 3882, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, IBSAM, ESIAB, Technopôle Brest-Iroise, 29280 Plouzané, France
| | - Sophie Le Panse
- Plateforme Merimage, Station Biologique de Roscoff, CNRS-UPMC, Place Georges Teissier, CS90074, 29688 Roscoff, Cedex, France
| | - Amélie Weill
- Université de Brest, EA 3882, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, IBSAM, ESIAB, Technopôle Brest-Iroise, 29280 Plouzané, France
| | - Jérôme Mounier
- Université de Brest, EA 3882, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, IBSAM, ESIAB, Technopôle Brest-Iroise, 29280 Plouzané, France
| | - Karim Rigalma
- Université de Brest, EA 3882, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, IBSAM, ESIAB, Technopôle Brest-Iroise, 29280 Plouzané, France.
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Wyatt TT, Wösten HAB, Dijksterhuis J. Fungal spores for dispersion in space and time. ADVANCES IN APPLIED MICROBIOLOGY 2016; 85:43-91. [PMID: 23942148 DOI: 10.1016/b978-0-12-407672-3.00002-2] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Spores are an integral part of the life cycle of the gross majority of fungi. Their morphology and the mode of formation are both highly variable among the fungi, as is their resistance to stressors. The main aim for spores is to be dispersed, both in space, by various mechanisms or in time, by an extended period of dormancy. Some fungal ascospores belong to the most stress-resistant eukaryotic cells described to date. Stabilization is a process in which biomolecules and complexes thereof are protected by different types of molecules against heat, drought, or other molecules. This review discusses the most important compounds that are known to protect fungal spores and also addresses the biophysics of cell protection. It further covers the phenomena of dormancy, breaking of dormancy, and early germination. Germination is the transition from a dormant cell toward a vegetative cell and includes a number of specific changes. Finally, the applied aspects of spore biology are discussed.
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Affiliation(s)
- Timon T Wyatt
- Department of Applied and Industrial Mycology, CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, Utrecht, The Netherlands
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Wang JB, St Leger RJ, Wang C. Advances in Genomics of Entomopathogenic Fungi. ADVANCES IN GENETICS 2016; 94:67-105. [PMID: 27131323 DOI: 10.1016/bs.adgen.2016.01.002] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Fungi are the commonest pathogens of insects and crucial regulators of insect populations. The rapid advance of genome technologies has revolutionized our understanding of entomopathogenic fungi with multiple Metarhizium spp. sequenced, as well as Beauveria bassiana, Cordyceps militaris, and Ophiocordyceps sinensis among others. Phylogenomic analysis suggests that the ancestors of many of these fungi were plant endophytes or pathogens, with entomopathogenicity being an acquired characteristic. These fungi now occupy a wide range of habitats and hosts, and their genomes have provided a wealth of information on the evolution of virulence-related characteristics, as well as the protein families and genomic structure associated with ecological and econutritional heterogeneity, genome evolution, and host range diversification. In particular, their evolutionary transition from plant pathogens or endophytes to insect pathogens provides a novel perspective on how new functional mechanisms important for host switching and virulence are acquired. Importantly, genomic resources have helped make entomopathogenic fungi ideal model systems for answering basic questions in parasitology, entomology, and speciation. At the same time, identifying the selective forces that act upon entomopathogen fitness traits could underpin both the development of new mycoinsecticides and further our understanding of the natural roles of these fungi in nature. These roles frequently include mutualistic relationships with plants. Genomics has also facilitated the rapid identification of genes encoding biologically useful molecules, with implications for the development of pharmaceuticals and the use of these fungi as bioreactors.
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Affiliation(s)
- J B Wang
- University of Maryland, College Park, MD, United States
| | - R J St Leger
- University of Maryland, College Park, MD, United States
| | - C Wang
- Chinese Academy of Sciences, Shanghai, China
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Zhao H, Lovett B, Fang W. Genetically Engineering Entomopathogenic Fungi. ADVANCES IN GENETICS 2016; 94:137-63. [PMID: 27131325 DOI: 10.1016/bs.adgen.2015.11.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Entomopathogenic fungi have been developed as environmentally friendly alternatives to chemical insecticides in biocontrol programs for agricultural pests and vectors of disease. However, mycoinsecticides currently have a small market share due to low virulence and inconsistencies in their performance. Genetic engineering has made it possible to significantly improve the virulence of fungi and their tolerance to adverse conditions. Virulence enhancement has been achieved by engineering fungi to express insect proteins and insecticidal proteins/peptides from insect predators and other insect pathogens, or by overexpressing the pathogen's own genes. Importantly, protein engineering can be used to mix and match functional domains from diverse genes sourced from entomopathogenic fungi and other organisms, producing insecticidal proteins with novel characteristics. Fungal tolerance to abiotic stresses, especially UV radiation, has been greatly improved by introducing into entomopathogens a photoreactivation system from an archaean and pigment synthesis pathways from nonentomopathogenic fungi. Conversely, gene knockout strategies have produced strains with reduced ecological fitness as recipients for genetic engineering to improve virulence; the resulting strains are hypervirulent, but will not persist in the environment. Coupled with their natural insect specificity, safety concerns can also be mitigated by using safe effector proteins with selection marker genes removed after transformation. With the increasing public concern over the continued use of synthetic chemical insecticides and growing public acceptance of genetically modified organisms, new types of biological insecticides produced by genetic engineering offer a range of environmentally friendly options for cost-effective control of insect pests.
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Affiliation(s)
- H Zhao
- Zhejiang University, Hangzhou, Zhejiang, China
| | - B Lovett
- University of Maryland, College Park, MD, United States
| | - W Fang
- Zhejiang University, Hangzhou, Zhejiang, China
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Trajectory and genomic determinants of fungal-pathogen speciation and host adaptation. Proc Natl Acad Sci U S A 2014; 111:16796-801. [PMID: 25368161 DOI: 10.1073/pnas.1412662111] [Citation(s) in RCA: 198] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Much remains unknown regarding speciation. Host-pathogen interactions are a major driving force for diversification, but the genomic basis for speciation and host shifting remains unclear. The fungal genus Metarhizium contains species ranging from specialists with very narrow host ranges to generalists that attack a wide range of insects. By genomic analyses of seven species, we demonstrated that generalists evolved from specialists via transitional species with intermediate host ranges and that this shift paralleled insect evolution. We found that specialization was associated with retention of sexuality and rapid evolution of existing protein sequences whereas generalization was associated with protein-family expansion, loss of genome-defense mechanisms, genome restructuring, horizontal gene transfer, and positive selection that accelerated after reinforcement of reproductive isolation. These results advance understanding of speciation and genomic signatures that underlie pathogen adaptation to hosts.
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Stress is the rule rather than the exception for Metarhizium. Curr Genet 2014; 61:253-61. [DOI: 10.1007/s00294-014-0447-9] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 08/07/2014] [Accepted: 08/17/2014] [Indexed: 01/20/2023]
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Xu C, Zhang X, Qian Y, Chen X, Liu R, Zeng G, Zhao H, Fang W. A high-throughput gene disruption methodology for the entomopathogenic fungus Metarhizium robertsii. PLoS One 2014; 9:e107657. [PMID: 25222118 PMCID: PMC4164657 DOI: 10.1371/journal.pone.0107657] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 08/14/2014] [Indexed: 11/19/2022] Open
Abstract
Systematic gene disruption is a direct way to interrogate a fungal genome to functionally characterize the full suite of genes involved in various biological processes. Metarhizium robertsii is extraordinarily versatile, and it is a pathogen of arthropods, a saprophyte and a beneficial colonizer of rhizospheres. Thus, M. robertsii can be used as a representative to simultaneously study several major lifestyles that are not shared by the "model" fungi Saccharomyces cerevisiae and Neurospora crassa; a systematic genetic analysis of M. robertsii will benefit studies in other fungi. In order to systematically disrupt genes in M. robertsii, we developed a high-throughput gene disruption methodology, which includes two technologies. One is the modified OSCAR-based, high-throughput construction of gene disruption plasmids. This technology involves two donor plasmids (pA-Bar-OSCAR with the herbicide resistance genes Bar and pA-Sur-OSCAR with another herbicide resistance gene Sur) and a recipient binary plasmid pPK2-OSCAR-GFP that was produced by replacing the Bar cassette in pPK2-bar-GFP with a ccdB cassette and recombination recognition sites. Using this technology, a gene disruption plasmid can be constructed in one cloning step in two days. The other is a highly efficient gene disruption technology based on homologous recombination using a Ku70 deletion mutant (ΔMrKu70) as the recipient strain. The deletion of MrKu70, a gene encoding a key component involved in nonhomologous end-joining DNA repair in fungi, dramatically increases the gene disruption efficiency. The frequency of disrupting the conidiation-associated gene Cag8 in ΔMrKu70 was 93% compared to 7% in the wild-type strain. Since ΔMrKu70 is not different from the wild-type strain in development, pathogenicity and tolerance to various abiotic stresses, it can be used as a recipient strain for a systematic gene disruption project to characterize the whole suite of genes involved in the biological processes of M. robertsii.
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Affiliation(s)
- Chuan Xu
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xing Zhang
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ying Qian
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiaoxuan Chen
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ran Liu
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Guohong Zeng
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Hong Zhao
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Weiguo Fang
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
- * E-mail:
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Liao X, Lu HL, Fang W, St Leger RJ. Overexpression of a Metarhizium robertsii HSP25 gene increases thermotolerance and survival in soil. Appl Microbiol Biotechnol 2013; 98:777-83. [PMID: 24265026 DOI: 10.1007/s00253-013-5360-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 10/16/2013] [Accepted: 10/21/2013] [Indexed: 12/19/2022]
Abstract
Temperature extremes are an important adverse factor limiting the effectiveness of microbial pest control agents. They reduce virulence and persistence in the plant root-colonizing insect pathogen Metarhizium robertsii. Small heat shock proteins have been shown to confer thermotolerance in many organisms. In this study, we report on the cloning and characterization of a small heat shock protein gene hsp25 from M. robertsii. hsp25 expression was upregulated when the fungus was grown at extreme temperatures (4, 35, and 42 °C) or in the presence of oxidative or osmotic agents. Expression of hsp25 in Escherichia coli increased bacterial thermotolerance confirming that hsp25 encodes a functional heat shock protein. Overexpressing hsp25 in M. robertsii increased fungal growth under heat stress either in nutrient-rich medium or on locust wings and enhanced the tolerance of heat shock-treated conidia to osmotic stress. In addition, overexpression of hsp25 increased the persistence of M. robertsii in rhizospheric soils in outdoor microcosms, though it did not affect survival in bulk soil, indicating that M. robertsii's survival in soil is dependent on interactions with plant roots.
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Affiliation(s)
- Xinggang Liao
- Department of Entomology, University of Maryland, College Park, MD, 20742, USA,
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Liao X, Fang W, Lin L, Lu HL, Leger RJS. Metarhizium robertsii produces an extracellular invertase (MrINV) that plays a pivotal role in rhizospheric interactions and root colonization. PLoS One 2013; 8:e78118. [PMID: 24205119 PMCID: PMC3804458 DOI: 10.1371/journal.pone.0078118] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Accepted: 09/17/2013] [Indexed: 01/22/2023] Open
Abstract
As well as killing pest insects, the rhizosphere competent insect-pathogenic fungus Metarhizium robertsii also boosts plant growth by providing nitrogenous nutrients and increasing resistance to plant pathogens. Plant roots secrete abundant nutrients but little is known about their utilization by Metarhizium spp. and the mechanistic basis of Metarhizium-plant associations. We report here that M. robertsii produces an extracellular invertase (MrInv) on plant roots. Deletion of MrInv (ΔMrInv) reduced M. robertsii growth on sucrose and rhizospheric exudates but increased colonization of Panicum virgatum and Arabidopsis thaliana roots. This could be accounted for by a reduction in carbon catabolite repression in ΔMrInv increasing production of plant cell wall-degrading depolymerases. A non-rhizosphere competent scarab beetle specialist Metarhizium majus lacks invertase which suggests that rhizospheric competence may be related to the sugar metabolism of different Metarhizium species.
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Affiliation(s)
- Xinggang Liao
- Department of Entomology, University of Maryland, College Park, Maryland, United States of America
| | - Weiguo Fang
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Liangcai Lin
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Hsiao-Ling Lu
- Department of Entomology, University of Maryland, College Park, Maryland, United States of America
| | - Raymond J. St. Leger
- Department of Entomology, University of Maryland, College Park, Maryland, United States of America
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Hu X, Zhang Y, Xiao G, Zheng P, Xia Y, Zhang X, St Leger RJ, Liu X, Wang C. Genome survey uncovers the secrets of sex and lifestyle in caterpillar fungus. ACTA ACUST UNITED AC 2013. [DOI: 10.1007/s11434-013-5929-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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36
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Fang W, Azimzadeh P, St. Leger RJ. Strain improvement of fungal insecticides for controlling insect pests and vector-borne diseases. Curr Opin Microbiol 2012; 15:232-8. [DOI: 10.1016/j.mib.2011.12.012] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Accepted: 12/22/2011] [Indexed: 01/28/2023]
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38
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Chang IF, Chen PJ, Shen CH, Hsieh TJ, Hsu YW, Huang BL, Kuo CI, Chen YT, Chu HA, Yeh KW, Huang LC. Proteomic profiling of proteins associated with the rejuvenation of Sequoia sempervirens (D. Don) Endl. Proteome Sci 2010; 8:64. [PMID: 21143964 PMCID: PMC3022872 DOI: 10.1186/1477-5956-8-64] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2010] [Accepted: 12/10/2010] [Indexed: 11/10/2022] Open
Abstract
Background Restoration of rooting competence is important for rejuvenation in Sequoia sempervirens (D. Don) Endl and is achieved by repeatedly grafting Sequoia shoots after 16 and 30 years of cultivation in vitro. Results Mass spectrometry-based proteomic analysis revealed three proteins that differentially accumulated in different rejuvenation stages, including oxygen-evolving enhancer protein 2 (OEE2), glycine-rich RNA-binding protein (RNP), and a thaumatin-like protein. OEE2 was found to be phosphorylated and a phosphopeptide (YEDNFDGNSNVSVMVpTPpTDK) was identified. Specifically, the protein levels of OEE2 increased as a result of grafting and displayed a higher abundance in plants during the juvenile and rejuvenated stages. Additionally, SsOEE2 displayed the highest expression levels in Sequoia shoots during the juvenile stage and less expression during the adult stage. The expression levels also steadily increased during grafting. Conclusion Our results indicate a positive correlation between the gene and protein expression patterns of SsOEE2 and the rejuvenation process, suggesting that this gene is involved in the rejuvenation of Sequoia sempervirens.
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Affiliation(s)
- Ing-Feng Chang
- Institute of Plant Biology, National Taiwan University, Taipei 106, Taiwan
| | - Peng-Jen Chen
- Institute of Plant Biology, National Taiwan University, Taipei 106, Taiwan
| | - Chin-Hui Shen
- Institute of Plant Biology, National Taiwan University, Taipei 106, Taiwan
| | - Tsung-Ju Hsieh
- Institute of Plant Biology, National Taiwan University, Taipei 106, Taiwan
| | - Ya-Wen Hsu
- Institute of Plant Biology, National Taiwan University, Taipei 106, Taiwan
| | - Bau-Lian Huang
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Ching-I Kuo
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Yu-Ting Chen
- Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung, Taiwan
| | - Hsiu-An Chu
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Kai-Wun Yeh
- Institute of Plant Biology, National Taiwan University, Taipei 106, Taiwan
| | - Li-Chun Huang
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
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Fang W, St Leger RJ. Mrt, a gene unique to fungi, encodes an oligosaccharide transporter and facilitates rhizosphere competency in Metarhizium robertsii. PLANT PHYSIOLOGY 2010; 154:1549-57. [PMID: 20837701 PMCID: PMC2971628 DOI: 10.1104/pp.110.163014] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The symbiotic associations between rhizospheric fungi and plants have enormous environmental impact. Fungi are crucial to plant health as antagonists of pathogens and herbivores and facilitate the uptake of soil nutrients. However, little is known about the plant products obtained by fungi in exchange or how they are transported through the symbiotic interface. Here, we demonstrate that sucrose and raffinose family oligosaccharides in root exudates are important for rhizosphere competence in the insect pathogen Metarhizium robertsii (formerly known as Metarhizium anisopliae). We identified mutants in the Metarhizium raffinose transporter (Mrt) gene of M. robertsii that grew poorly in root exudate and were greatly reduced in rhizosphere competence on grass roots. Studies on sugar uptake, including competition assays, revealed that MRT was a sucrose and galactoside transporter. Disrupting MRT resulted in greatly reduced or no growth on sucrose and galactosides but did not affect growth on monosaccharides or oligosaccharides composed entirely of glucose subunits. Consistent with this, expression of Mrt is exclusively up-regulated by galactosides and sucrose. Expressing a green fluorescent protein gene under the control of the Mrt promoter confirmed that MRT was expressed by germlings in the vicinity of grass roots but not in surrounding bulk soil. Disrupting Mrt did not reduce virulence to insects, demonstrating that Mrt is exclusively involved in M. robertsii's interactions with plants. To our knowledge, MRT is the first oligosaccharide transporter identified and characterized in a fungus and is unique to filamentous fungi, but homologous genes in Magnaporthe, Ustilago, Aspergillus, Fusarium, Epichloe, and Penicillium species indicate that oligosaccharide transport is of widespread significance.
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Affiliation(s)
- Weiguo Fang
- Department of Entomology, University of Maryland, College Park, Maryland 20742, USA.
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