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Chowdhury J, Kemppainen M, Delhomme N, Shutava I, Zhou J, Takahashi J, Pardo AG, Lundberg‐Felten J. Laccaria bicolor pectin methylesterases are involved in ectomycorrhiza development with Populus tremula × Populus tremuloides. New Phytol 2022; 236:639-655. [PMID: 35794841 PMCID: PMC9796311 DOI: 10.1111/nph.18358] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 06/29/2022] [Indexed: 06/15/2023]
Abstract
The development of ectomycorrhizal (ECM) symbioses between soil fungi and tree roots requires modification of root cell walls. The pectin-mediated adhesion between adjacent root cells loosens to accommodate fungal hyphae in the Hartig net, facilitating nutrient exchange between partners. We investigated the role of fungal pectin modifying enzymes in Laccaria bicolor for ECM formation with Populus tremula × Populus tremuloides. We combine transcriptomics of cell-wall-related enzymes in both partners during ECM formation, immunolocalisation of pectin (Homogalacturonan, HG) epitopes in different methylesterification states, pectin methylesterase (PME) activity assays and functional analyses of transgenic L. bicolor to uncover pectin modification mechanisms and the requirement of fungal pectin methylesterases (LbPMEs) for ECM formation. Immunolocalisation identified remodelling of pectin towards de-esterified HG during ECM formation, which was accompanied by increased LbPME1 expression and PME activity. Overexpression or RNAi of the ECM-induced LbPME1 in transgenic L. bicolor lines led to reduced ECM formation. Hartig Nets formed with LbPME1 RNAi lines were shallower, whereas those formed with LbPME1 overexpressors were deeper. This suggests that LbPME1 plays a role in ECM formation potentially through HG de-esterification, which initiates loosening of adjacent root cells to facilitate Hartig net formation.
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Affiliation(s)
- Jamil Chowdhury
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science CenterSwedish University of Agricultural Sciences90183UmeåSweden
- Department of Plant Physiology, Umeå Plant Science CenterUmeå University90187UmeåSweden
| | - Minna Kemppainen
- Laboratory of Molecular Mycology, Department of Science and Technology, Institute of Basic and Applied MicrobiologyNational University of Quilmes (UNQ), and National Scientific and Technical Research Council (CONICET)B1876BXDBernalArgentina
| | - Nicolas Delhomme
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science CenterSwedish University of Agricultural Sciences90183UmeåSweden
| | - Iryna Shutava
- Department of Plant Physiology, Umeå Plant Science CenterUmeå University90187UmeåSweden
| | - Jingjing Zhou
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science CenterSwedish University of Agricultural Sciences90183UmeåSweden
- Department of Plant Physiology, Umeå Plant Science CenterUmeå University90187UmeåSweden
| | - Junko Takahashi
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science CenterSwedish University of Agricultural Sciences90183UmeåSweden
| | - Alejandro G. Pardo
- Laboratory of Molecular Mycology, Department of Science and Technology, Institute of Basic and Applied MicrobiologyNational University of Quilmes (UNQ), and National Scientific and Technical Research Council (CONICET)B1876BXDBernalArgentina
| | - Judith Lundberg‐Felten
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science CenterSwedish University of Agricultural Sciences90183UmeåSweden
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Kang H, Chen X, Kemppainen M, Pardo AG, Veneault-Fourrey C, Kohler A, Martin FM. The small secreted effector protein MiSSP7.6 of Laccaria bicolor is required for the establishment of ectomycorrhizal symbiosis. Environ Microbiol 2020; 22:1435-1446. [PMID: 32090429 DOI: 10.1111/1462-2920.14959] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 02/19/2020] [Accepted: 02/20/2020] [Indexed: 11/29/2022]
Abstract
To establish and maintain a symbiotic relationship, the ectomycorrhizal fungus Laccaria bicolor releases mycorrhiza-induced small secreted proteins (MiSSPs) into host roots. Here, we have functionally characterized the MYCORRHIZA-iNDUCED SMALL SECRETED PROTEIN OF 7.6 kDa (MiSSP7.6) from L. bicolor by assessing its induced expression in ectomycorrhizae, silencing its expression by RNAi, and tracking in planta subcellular localization of its protein product. We also carried out yeast two-hybrid assays and bimolecular fluorescence complementation analysis to identify possible protein targets of the MiSSP7.6 effector in Populus roots. We showed that MiSSP7.6 expression is upregulated in ectomycorrhizal rootlets and associated extramatrical mycelium during the late stage of symbiosis development. RNAi mutants with a decreased MiSSP7.6 expression have a lower mycorrhization rate, suggesting a key role in the establishment of the symbiosis with plants. MiSSP7.6 is secreted, and it localizes both to the nuclei and cytoplasm in plant cells. MiSSP7.6 protein was shown to interact with two Populus Trihelix transcription factors. Furthermore, when coexpressed with one of the Trihelix transcription factors, MiSSP7.6 is localized to plant nuclei only. Our data suggest that MiSSP7.6 is a novel secreted symbiotic effector and is a potential determinant for ectomycorrhiza formation.
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Affiliation(s)
- Heng Kang
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.,University of Lorraine, Institut National de la Recherche Agronomique, UMR Interactions Arbres/Microorganismes, Laboratoire d'Excellence ARBRE, Centre INRA-Grand Est, Champenoux, France
| | - Xin Chen
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Minna Kemppainen
- Laboratorio de Micología Molecular, Instituto de Microbiología Básica y Aplicada, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bernal, Provincia de Buenos Aires, Argentina
| | - Alejandro G Pardo
- Laboratorio de Micología Molecular, Instituto de Microbiología Básica y Aplicada, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bernal, Provincia de Buenos Aires, Argentina
| | - Claire Veneault-Fourrey
- University of Lorraine, Institut National de la Recherche Agronomique, UMR Interactions Arbres/Microorganismes, Laboratoire d'Excellence ARBRE, Centre INRA-Grand Est, Champenoux, France
| | - Annegret Kohler
- University of Lorraine, Institut National de la Recherche Agronomique, UMR Interactions Arbres/Microorganismes, Laboratoire d'Excellence ARBRE, Centre INRA-Grand Est, Champenoux, France
| | - Francis M Martin
- University of Lorraine, Institut National de la Recherche Agronomique, UMR Interactions Arbres/Microorganismes, Laboratoire d'Excellence ARBRE, Centre INRA-Grand Est, Champenoux, France
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Pellegrin C, Daguerre Y, Ruytinx J, Guinet F, Kemppainen M, Frey NFD, Puech‐Pagès V, Hecker A, Pardo AG, Martin FM, Veneault‐Fourrey C. Laccaria bicolor
MiSSP8 is a small‐secreted protein decisive for the establishment of the ectomycorrhizal symbiosis. Environ Microbiol 2019; 21:3765-3779. [DOI: 10.1111/1462-2920.14727] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 06/18/2019] [Accepted: 06/27/2019] [Indexed: 11/29/2022]
Affiliation(s)
- Clément Pellegrin
- INRA, UMR1136Interactions Arbres/microorganismes Centre Grand‐Est Champenoux France
- UMR 1136, Interactions Arbres/Microorganismes (IAM), Faculté des Sciences et TechnologiesUniversité de Lorraine Vandœuvre lès Nancy France
| | - Yohann Daguerre
- INRA, UMR1136Interactions Arbres/microorganismes Centre Grand‐Est Champenoux France
- UMR 1136, Interactions Arbres/Microorganismes (IAM), Faculté des Sciences et TechnologiesUniversité de Lorraine Vandœuvre lès Nancy France
| | - Joske Ruytinx
- INRA, UMR1136Interactions Arbres/microorganismes Centre Grand‐Est Champenoux France
- UMR 1136, Interactions Arbres/Microorganismes (IAM), Faculté des Sciences et TechnologiesUniversité de Lorraine Vandœuvre lès Nancy France
| | - Frédéric Guinet
- INRA, UMR1136Interactions Arbres/microorganismes Centre Grand‐Est Champenoux France
- UMR 1136, Interactions Arbres/Microorganismes (IAM), Faculté des Sciences et TechnologiesUniversité de Lorraine Vandœuvre lès Nancy France
| | - Minna Kemppainen
- Laboratorio de Micología Molecular, Departamento de Ciencia y TecnologıaUniversidad Nacional de Quilmes and CONICET Roque Sáenz Peña 352 B1876 Bernal Provincia de Buenos Aires Argentina
| | - Nicolas Frei dit Frey
- Laboratoire de Recherche en Sciences VégétalesUniversité de Toulouse, CNRS, UPS 24 chemin de Borde Rouge, Auzeville, BP42617 31326 Castanet Tolosan France
| | - Virginie Puech‐Pagès
- Laboratoire de Recherche en Sciences VégétalesUniversité de Toulouse, CNRS, UPS 24 chemin de Borde Rouge, Auzeville, BP42617 31326 Castanet Tolosan France
| | - Arnaud Hecker
- INRA, UMR1136Interactions Arbres/microorganismes Centre Grand‐Est Champenoux France
- UMR 1136, Interactions Arbres/Microorganismes (IAM), Faculté des Sciences et TechnologiesUniversité de Lorraine Vandœuvre lès Nancy France
| | - Alejandro G. Pardo
- Laboratorio de Micología Molecular, Departamento de Ciencia y TecnologıaUniversidad Nacional de Quilmes and CONICET Roque Sáenz Peña 352 B1876 Bernal Provincia de Buenos Aires Argentina
| | - Francis M. Martin
- INRA, UMR1136Interactions Arbres/microorganismes Centre Grand‐Est Champenoux France
- UMR 1136, Interactions Arbres/Microorganismes (IAM), Faculté des Sciences et TechnologiesUniversité de Lorraine Vandœuvre lès Nancy France
| | - Claire Veneault‐Fourrey
- INRA, UMR1136Interactions Arbres/microorganismes Centre Grand‐Est Champenoux France
- UMR 1136, Interactions Arbres/Microorganismes (IAM), Faculté des Sciences et TechnologiesUniversité de Lorraine Vandœuvre lès Nancy France
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Stephan BI, Alvarez Crespo MC, Kemppainen MJ, Pardo AG. Agrobacterium-mediated insertional mutagenesis in the mycorrhizal fungus Laccaria bicolor. Curr Genet 2016; 63:215-227. [PMID: 27387518 DOI: 10.1007/s00294-016-0627-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 06/22/2016] [Accepted: 06/24/2016] [Indexed: 11/24/2022]
Abstract
Agrobacterium-mediated gene transfer (AMT) is extensively employed as a tool in fungal functional genomics and accordingly, in previous studies we used AMT on a dikaryotic strain of the ectomycorrhizal basidiomycete Laccaria bicolor. The interest in this fungus derives from its capacity to establish a symbiosis with tree roots, thereby playing a major role in nutrient cycling of forest ecosystems. The ectomycorrhizal symbiosis is a highly complex interaction involving many genes from both partners. To advance in the functional characterization of fungal genes, AMT was used on a monokaryotic L. bicolor. A collection of over 1200 transgenic strains was produced, of which 200 randomly selected strains were analyzed for their genomic T-DNA insertion patterns. By means of insertional mutagenesis, a number of transgenic strains were obtained displaying differential growth features. Moreover, mating with a compatible strain resulted in dikaryons that retained altered phenotypic features of the transgenic monokaryon. The analysis of the T-DNA integration pattern revealed mostly similar results to those reported in earlier studies, confirming the usefulness of AMT on different genetic backgrounds of L. bicolor. Taken together, our studies display the great versatility and potentiality of AMT as a tool for the genetic characterization of L. bicolor.
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Affiliation(s)
- B I Stephan
- Laboratorio de Micología Molecular, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes and Consejo Nacional de Investigaciones Científicas y Técnicas, Roque Saenz Peña 352, B1876BXD, Bernal, Provincia de Buenos Aires, Argentina
| | - M C Alvarez Crespo
- Laboratorio de Micología Molecular, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes and Consejo Nacional de Investigaciones Científicas y Técnicas, Roque Saenz Peña 352, B1876BXD, Bernal, Provincia de Buenos Aires, Argentina
| | - M J Kemppainen
- Laboratorio de Micología Molecular, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes and Consejo Nacional de Investigaciones Científicas y Técnicas, Roque Saenz Peña 352, B1876BXD, Bernal, Provincia de Buenos Aires, Argentina
| | - A G Pardo
- Laboratorio de Micología Molecular, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes and Consejo Nacional de Investigaciones Científicas y Técnicas, Roque Saenz Peña 352, B1876BXD, Bernal, Provincia de Buenos Aires, Argentina.
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Xu H, Cooke JEK, Kemppainen M, Pardo AG, Zwiazek JJ. Hydraulic conductivity and aquaporin transcription in roots of trembling aspen (Populus tremuloides) seedlings colonized by Laccaria bicolor. Mycorrhiza 2016; 26:441-451. [PMID: 26861480 DOI: 10.1007/s00572-016-0681-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Accepted: 01/26/2016] [Indexed: 06/05/2023]
Abstract
Ectomycorrhizal fungi have been reported to increase root hydraulic conductivity (L pr) by altering apoplastic and plasma membrane intrinsic protein (PIP)-mediated cell-to-cell water transport pathways in associated roots, or to have little effect on root water transport, depending on the interacting species and imposed stresses. In this study, we investigated the water transport properties and PIP transcription in roots of aspen (Populus tremuloides) seedlings colonized by the wild-type strain of Laccaria bicolor and by strains overexpressing a major fungal water-transporting aquaporin JQ585595. Inoculation of aspen seedlings with L. bicolor resulted in about 30 % colonization rate of root tips, which developed dense mantle and the Hartig net that was restricted in the modified root epidermis. Transcript abundance of the aspen aquaporins PIP1;2, PIP2;1, and PIP2;2 decreased in colonized root tips. Root colonization by JQ585595-overexpressing strains had no significant impact on seedling shoot water potentials, gas exchange, or dry mass; however, it led to further decrease in transcript abundance of PIP1;2 and PIP2;3 and the significantly lower L pr than in non-inoculated roots. These results, taken together with our previous study that showed enhanced root water hydraulics of L. bicolor-colonized white spruce (Picea glauca), suggest that the impact of L. bicolor on root hydraulics varies by the ectomycorrhiza-associated tree species.
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Affiliation(s)
- Hao Xu
- Department of Renewable Resources, University of Alberta, Edmonton, T6G 2E3, Canada
| | - Janice E K Cooke
- Department of Biological Sciences, University of Alberta, Edmonton, T6G 2E9, Canada
| | - Minna Kemppainen
- Laboratorio de Micología Molecular, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bernal, Argentina
| | - Alejandro G Pardo
- Laboratorio de Micología Molecular, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bernal, Argentina
| | - Janusz J Zwiazek
- Department of Renewable Resources, University of Alberta, Edmonton, T6G 2E3, Canada.
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Navarro-RóDenas A, Xu H, Kemppainen M, Pardo AG, Zwiazek JJ. Laccaria bicolor aquaporin LbAQP1 is required for Hartig net development in trembling aspen (Populus tremuloides). Plant Cell Environ 2015; 38:2475-86. [PMID: 25857333 DOI: 10.1111/pce.12552] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 03/22/2015] [Indexed: 05/27/2023]
Abstract
The development of ectomycorrhizal associations is crucial for growth of many forest trees. However, the signals that are exchanged between the fungus and the host plant during the colonization process are still poorly understood. In this study, we have identified the relationship between expression patterns of Laccaria bicolor aquaporin LbAQP1 and the development of ectomycorrhizal structures in trembling aspen (Populus tremuloides) seedlings. The peak expression of LbAQP1 was 700-fold higher in the hyphae within the root than in the free-living mycelium after 24 h of direct interaction with the roots. Moreover, in LbAQP1 knock-down strains, a non-mycorrhizal phenotype was developed without the Hartig net and the expression of the mycorrhizal effector protein MiSSP7 quickly declined after an initial peak on day 5 of interaction of the fungal hyphae with the roots. The increase in the expression of LbAQP1 required a direct contact of the fungus with the root and it modulated the expression of MiSSP7. We have also determined that LbAQP1 facilitated NO, H2 O2 and CO2 transport when heterologously expressed in yeast. The report demonstrates that the L. bicolor aquaporin LbAQP1 acts as a molecular signalling channel, which is fundamental for the development of Hartig net in root tips of P. tremuloides.
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Affiliation(s)
| | - Hao Xu
- Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2E3, Canada
| | - Minna Kemppainen
- Laboratorio de Micología Molecular, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bernal, Provincia de Buenos Aires, B1876BXD, Argentina
| | - Alejandro G Pardo
- Laboratorio de Micología Molecular, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bernal, Provincia de Buenos Aires, B1876BXD, Argentina
| | - Janusz J Zwiazek
- Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2E3, Canada
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Xu H, Kemppainen M, El Kayal W, Lee SH, Pardo AG, Cooke JEK, Zwiazek JJ. Overexpression of Laccaria bicolor aquaporin JQ585595 alters root water transport properties in ectomycorrhizal white spruce (Picea glauca) seedlings. New Phytol 2015; 205:757-70. [PMID: 25323307 DOI: 10.1111/nph.13098] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Accepted: 08/27/2014] [Indexed: 05/20/2023]
Abstract
The contribution of hyphae to water transport in ectomycorrhizal (ECM) white spruce (Picea glauca) seedlings was examined by altering expression of a major water-transporting aquaporin in Laccaria bicolor. Picea glauca was inoculated with wild-type (WT), mock transgenic or L. bicolor aquaporin JQ585595-overexpressing (OE) strains and exposed to root temperatures ranging from 5 to 20°C to examine the root water transport properties, physiological responses and plasma membrane intrinsic protein (PIP) expression in colonized plants. Mycorrhization increased shoot water potential, transpiration, net photosynthetic rates, root hydraulic conductivity and root cortical cell hydraulic conductivity in seedlings. At 20°C, OE plants had higher root hydraulic conductivity compared with WT plants and the increases were accompanied by higher expression of P. glauca PIP GQ03401_M18.1 in roots. In contrast to WT L. bicolor, the effects of OE fungi on root and root cortical cell hydraulic conductivities were abolished at 10 and 5°C in the absence of major changes in the examined transcript levels of P. glauca root PIPs. The results provide evidence for the importance of fungal aquaporins in root water transport of mycorrhizal plants. They also demonstrate links between hyphal water transport, root aquaporin expression and root water transport in ECM plants.
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Affiliation(s)
- Hao Xu
- Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2E3, Canada
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Kemppainen MJ, Pardo AG. LbNrt RNA silencing in the mycorrhizal symbiont Laccaria bicolor reveals a nitrate-independent regulatory role for a eukaryotic NRT2-type nitrate transporter. Environ Microbiol Rep 2013; 5:353-366. [PMID: 23754716 DOI: 10.1111/1758-2229.12029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2012] [Accepted: 12/13/2012] [Indexed: 06/02/2023]
Abstract
Fungal nitrogen metabolism plays a fundamental role in function of mycorrhizal symbiosis and consequently in nutrient cycling of terrestrial ecosystems. Despite its global ecological relevance the information on control and molecular regulation of nitrogen utilization in mycorrhizal fungi is very limited. We have extended the nitrate utilization RNA silencing studies of the model mycorrhizal basidiomycete, Laccaria bicolor, by altering the expression of LbNrt, the sole nitrate transporter-encoding gene of the fungus. Here we report the first nutrient transporter mutants for mycorrhizal fungi. Silencing of LbNrt results in fungal strains with minimal detectable LbNrt transcript levels, significantly reduced growth capacity on nitrate and altered symbiotic interaction with poplar. Transporter silencing also creates marked co-downregulation of whole Laccaria fHANT-AC (fungal high-affinity nitrate assimilation cluster). Most importantly, this effect on the nitrate utilization pathway appears independent of extracellular nitrate or nitrogen status of the fungus. Our results indicate a novel and central nitrate uptake-independent regulatory role for a eukaryotic nitrate transporter. The possible cellular mechanisms behind this regulation mode are discussed in the light of current knowledge on NRT2-type nitrate transporters in different eukaryotes.
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Affiliation(s)
- Minna J Kemppainen
- Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Bernal, Provincia de Buenos Aires, Argentina
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Kemppainen MJ, Pardo AG. Gene knockdown by ihpRNA-triggering in the ectomycorrhizal basidiomycete fungus Laccaria bicolor. Bioeng Bugs 2012; 1:354-8. [PMID: 21326837 DOI: 10.4161/bbug.1.5.12385] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Revised: 05/07/2010] [Accepted: 05/11/2010] [Indexed: 11/19/2022] Open
Abstract
Ectomycorrhiza (ECM) is a mutualistic association between fungi and the roots of the vast majority of trees. These include numerous ecologically and economically relevant species and the participating fungal symbionts are predominantly filamentous basidiomycetes. In natural ecosystems the plant nutrient uptake from soil takes place via the extraradical mycelia of these ECM mycosimbionts as a trade for plant photosyntates. The symbiotic phase in the life cycle of ECM basidiomycetes is the dikaryotic hyphae. Therefore, studies on symbiotic relevant gene functions require the inactivation of both gene copies in these dikaryotic fungi. RNA silencing is a eukaryotic sequence homology-dependent degradation of target RNAs which is believed to have evolved as a protection mechanism against invading nucleic acids. In different eukaryotic organisms, including fungi, the RNA silencing pathway can be artificially triggered to target and degrade gene transcripts of interest, resulting in gene knock-down. Most importantly, RNA silencing can act at the cytosolic level affecting mRNAs originating from several gene copies and different nuclei thus offering an efficient means of altering gene expression in dikaryotic organisms. Therefore, the pHg/pSILBAγ silencing vector was constructed for efficient RNA silencing triggering in the model mycorrhizal fungus Laccaria bicolor. This cloning vector carries the Agaricus bisporus gpdII-promoter, two multiple cloning sites separated by a L. bicolor nitrate reductase intron and the Aspergillus nidulans trpC terminator. pSILBAγ allows an easy two-step PCR-cloning of hairpin sequences to be expressed in basidiomycetes. With one further cloning step into pHg, a pCAMBIA1300-based binary vector carrying a hygromycin resistance cassette, makes the pHg/pSILBAγ plasmid compatible with Agrobacterium-mediated transformation. The pHg/pSILBAγ-system results in predominantly single integrations of RNA silencing triggering T-DNAs in the fungal genome and the integration sites of the transgenes can be resolved by plasmid rescue. Besides the optimized use in L. bicolor, general consideration was taken to build a vector system with maximum compatibility with other homobasidiomycetes and different transformation techniques.
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Affiliation(s)
- Minna J Kemppainen
- Laboratorio de Micología Molecular, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Provincia de Buenos Aires, Argentina
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Abstract
Most boreal and temperate forest trees form a mutualistic symbiosis with soil borne fungi called ectomycorrhiza (ECM). In this association both partners benefit due to nutrient exchange at the symbiotic interface. Laccaria bicolor is the first mycorrhizal fungus with its genome sequenced thus making possible for the first time to analyze genome scale gene expression profiles of a mutualistic fungus. However, in order to be able to take full advantage of the genome sequence, reverse genetic tools are needed. Among them a high throughput transformation system is crucial. Herein we present a detailed protocol for genetic transformation of L. bicolor by means of Agrobacterium tumefaciens with emphasis on critical steps affecting the success and efficiency of the approach.
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Affiliation(s)
- Minna J Kemppainen
- Laboratorio de Micología, Departmento de Ciencia y Technología, Universidad Nacional de Quilmes and Consejo Nacional de Investigaciones Cientificas y Técnicas (CONICET), Bernal, Buenos Aires, Argentina
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Plett JM, Kemppainen M, Kale SD, Kohler A, Legué V, Brun A, Tyler BM, Pardo AG, Martin F. A secreted effector protein of Laccaria bicolor is required for symbiosis development. Curr Biol 2011; 21:1197-203. [PMID: 21757352 DOI: 10.1016/j.cub.2011.05.033] [Citation(s) in RCA: 253] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 05/05/2011] [Accepted: 05/17/2011] [Indexed: 12/11/2022]
Abstract
Soil-borne mutualistic fungi, such as the ectomycorrhizal fungi, have helped shape forest communities worldwide over the last 180 million years through a mutualistic relationship with tree roots in which the fungal partner provides a large array of nutrients to the plant host in return for photosynthetically derived sugars. This exchange is essential for continued growth and productivity of forest trees, especially in nutrient-poor soils. To date, the signals from the two partners that mediate this symbiosis have remained uncharacterized. Here we demonstrate that MYCORRHIZAL iNDUCED SMALL SECRETED PROTEIN 7 (MiSSP7), the most highly symbiosis-upregulated gene from the ectomycorrhizal fungus Laccaria bicolor, encodes an effector protein indispensible for the establishment of mutualism. MiSSP7 is secreted by the fungus upon receipt of diffusible signals from plant roots, imported into the plant cell via phosphatidylinositol 3-phosphate-mediated endocytosis, and targeted to the plant nucleus where it alters the transcriptome of the plant cell. L. bicolor transformants with reduced expression of MiSSP7 do not enter into symbiosis with poplar roots. MiSSP7 resembles effectors of pathogenic fungi, nematodes, and bacteria that are similarly targeted to the plant nucleus to promote colonization of the plant tissues and thus can be considered a mutualism effector.
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Affiliation(s)
- Jonathan M Plett
- UMR INRA/UHP 1136, Interactions Arbres/Micro-organismes, Centre INRA de Nancy, 54280 Champenoux, France
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12
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Pardo AG. BT-engineered bugs versus insect pests. Bioeng Bugs 2010; 1:367-8. [PMID: 21326839 DOI: 10.4161/bbug.1.5.13656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Accepted: 09/17/2010] [Indexed: 11/19/2022] Open
Affiliation(s)
- Alejandro G Pardo
- Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), (B1876BXD) Bernal, Provincia de Buenos Aires, Argentina.
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Kemppainen MJ, Alvarez Crespo MC, Pardo AG. fHANT-AC genes of the ectomycorrhizal fungus Laccaria bicolor are not repressed by l-glutamine allowing simultaneous utilization of nitrate and organic nitrogen sources. Environ Microbiol Rep 2010; 2:541-53. [PMID: 23766224 DOI: 10.1111/j.1758-2229.2009.00111.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
In boreal and temperate forest ectomycorrhizal fungi play a crucial role in nitrogen cycling by assimilating nitrogenous compounds from soil and transferring them to tree hosts. The expression profile of fHANT-AC genes, nitrate transporter (Lbnrt), nitrate reductase (Lbnr) and nitrite reductase (Lbnir), responsible for nitrate utilization in the ectomycorrhizal fungus Laccaria bicolor, was studied on variable N regimens. The three genes were shown to be under a common regulation: repressed in the presence of ammonium while growth on nitrate resulted in high transcripts accumulation. The presence of nitrate was shown not to be indispensable for activation of Laccaria fHANT-AC as also N starvation and growth on urea and l-asparagine resulted in high transcript levels. Equally high expression of Laccaria fHANT-AC genes was detected in mycelia grown on variable concentrations of l-glutamine. This finding shows that in L. bicolor N metabolite repression of fHANT-AC is not signalled via l-glutamine like described in ascomycetes. The expression patterns of Lbnrt and Lbnir were also studied in an Lbnr RNA-silenced Laccaria strain. No differences were observed on the N source regulation or the degree of transcript accumulation of these genes, indicating that the presence of high nitrate reductase activity is not a core regulator of L. bicolor fHANT-AC expression. The simultaneous utilization of nitrate and organic N sources, already suggested by high transcript levels of Laccaria fHANT-AC genes on organic N, was supported by the increase of culture medium pH as a result of nitrate transporter activity. The possible ecological and evolutionary significance of the herein reported high regulatory flexibility of Laccaria nitrate utilization pathway for ectomycorrizal fungi and the ectomycorrhizal symbiosis is discussed.
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Affiliation(s)
- Minna J Kemppainen
- Laboratorio de Micología Molecular, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Roque Sáenz Peña 352 (B1876BXD) Bernal, Provincia de Buenos Aires, Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina. Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT), Buenos Aires, Argentina
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Kemppainen MJ, Pardo AG. pHg/pSILBAγ vector system for efficient gene silencing in homobasidiomycetes: optimization of ihpRNA - triggering in the mycorrhizal fungus Laccaria bicolor. Microb Biotechnol 2010. [PMCID: PMC3836586 DOI: 10.1111/j.1751-7915.2009.00133.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Ludemann V, Greco M, Rodríguez MP, Basílico JC, Pardo AG. Conidial production by Penicillium nalgiovense for use as starter cultures in dry fermented sausages by solid state fermentation. Lebensm Wiss Technol 2010. [DOI: 10.1016/j.lwt.2009.07.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ludemann V, Pose G, Moavro A, Maliaviabarrena MG, Fandiño R, Ripoll G, Basílico JC, Pardo AG. Toxicological assessment of Penicillium nalgiovense strains for use as starter cultures in the manufacture of dry fermented sausages. J Food Prot 2009; 72:1666-70. [PMID: 19722398 DOI: 10.4315/0362-028x-72.8.1666] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The use of fungal starter strains in the casing of dry fermented sausages allows standardization of the manufacturing process and ensures consumer safety. Penicillium nalgiovense is normally used for this purpose. Even though this species is reported as safe with respect to the production of the most common mycotoxins, its safety may be strain specific. The aim of the present work was to assess the toxicogenic potential of nine P. nalgiovense strains isolated from dry fermented sausages that were previously suitable as starters. The strains were tested for toxicity on brine shrimp larvae and the human cell line MCF7, for mutagenicity in the Ames test, and for antibacterial activity against gram-positive and gram-negative bacteria. According to our results, several P. nalgiovense strains were positive in more than one bioassay. Therefore, it is important to use different toxicological assays when characterizing strains intended for food use. Strains S1-2 and S14-4, which belong to biotypes 6 and 5, respectively, were nontoxigenic under the conditions tested. Overall, strain S1-2 of P. nalgiovense proved to be best suited as a starter in dry fermented sausage manufacture because in addition of being nontoxicogenic it produces white conidia, which is a desirable feature.
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Affiliation(s)
- Vanesa Ludemann
- Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Bernal, Provincia de Buenos Aires, Argentina.
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Kemppainen M, Duplessis S, Martin F, Pardo AG. RNA silencing in the model mycorrhizal fungusLaccaria bicolor: gene knock-down of nitrate reductase results in inhibition of symbiosis withPopulus. Environ Microbiol 2009; 11:1878-96. [DOI: 10.1111/j.1462-2920.2009.01912.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Kemppainen MJ, Pardo AG. pHg/pSILBAγ vector system for efficient gene silencing in homobasidiomycetes: optimization of ihpRNA - triggering in the mycorrhizal fungus Laccaria bicolor. Microb Biotechnol 2009; 3:178-200. [PMID: 21255319 PMCID: PMC3836584 DOI: 10.1111/j.1751-7915.2009.00122.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
pSILBAγ silencing vector was constructed for efficient RNA silencing triggering in the model mycorrhizal fungus Laccaria bicolor. This cloning vector carries the Agaricus bisporus gpdII promoter, two multiple cloning sites separated by a L. bicolor nitrate reductase intron and the Aspergillus nidulans trpC terminator. pSILBAγ allows an easy oriented two‐step PCR cloning of hairpin sequences to be expressed in basidiomycetes. With one further cloning step into pHg, a pCAMBIA1300‐based binary vector carrying a hygromycin resistance cassette, the pHg/pSILBAγ plasmid is used for Agrobacterium‐mediated transformation. The pHg/pSILBAγ system results in predominantly single integrations of RNA silencing triggering T‐DNAs in the fungal genome and the integration sites of the transgenes can be resolved by plasmid rescue. pSILBAγ construct and two other pSILBA plasmid variants (pSILBA and pSILBAα) were evaluated for their capacity to silence Laccaria nitrate reductase gene. While all pSILBA variants tested resulted in up to 65–76% of transformants with reduced growth on nitrate, pSILBAγ produced the highest number (65%) of strongly affected fungal strains. The strongly silenced phenotype was shown to correlate with T‐DNA integration in transcriptionally active genomic sites. pHg/pSILBAγ was shown to produce T‐DNAs with minimum CpG methylation in transgene promoter regions which assures the maximum silencing trigger production in Laccaria. Methylation of the target endogene was only slight in RNA silencing triggered with constructs carrying an intronic spacer hairpin sequence. The silencing capacity of the pHg/pSILBAγ was further tested with Laccaria inositol‐1,4,5‐triphosphate 5‐phosphatase gene. Besides its use in silencing triggering, the herein described plasmid system can also be used for transgene expression in Laccaria. pHg/pSILBAγ silencing system is optimized for L. bicolor but it should be highly useful also for other homobasidiomycetes, group of fungi currently lacking molecular tools for RNA silencing.
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Affiliation(s)
- Minna J Kemppainen
- Laboratorio de Micología Molecular, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Roque Sáenz Peña 352, (B1876BXD) Bernal, Provincia de Buenos Aires, Argentina
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Kemppainen M, Duplessis S, Martin F, Pardo AG. T-DNA insertion, plasmid rescue and integration analysis in the model mycorrhizal fungus Laccaria bicolor. Microb Biotechnol 2008; 1:258-69. [PMID: 21261845 PMCID: PMC3815887 DOI: 10.1111/j.1751-7915.2008.00029.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2007] [Accepted: 01/24/2008] [Indexed: 12/04/2022] Open
Abstract
Ectomycorrhiza is a mutualistic symbiosis formed between fine roots of trees and the mycelium of soil fungi. This symbiosis plays a key role in forest ecosystems for the mineral nutrition of trees and the biology of the fungal communities associated. The characterization of genes involved in developmental and metabolic processes is important to understand the complex interactions that control the ectomycorrhizal symbiosis. Agrobacterium-mediated gene transfer (AMT) in fungi is currently opening a new era for fungal research. As whole genome sequences of several fungi are being released studies about T-DNA integration patterns are needed in order to understand the integration mechanisms involved and to evaluate the AMT as an insertional mutagenesis tool for different fungal species. The first genome sequence of a mycorrhizal fungus, the basidiomycete Laccaria bicolor, became public in July 2006. Release of Laccaria genome sequence and the availability of AMT makes this fungus an excellent model for functional genomic studies in ectomycorrhizal research. No data on the integration pattern in Laccaria genome were available, thus we optimized a plasmid rescue approach for this fungus. To this end the transformation vector (pHg/pBSk) was constructed allowing the rescue of the T-DNA right border (RB)-genomic DNA junctions in Escherichia coli. Fifty-one Agrobacterium-transformed fungal strains, picked up at random from a larger collection of T-DNA tagged strains (about 500), were analysed. Sixty-nine per cent were successfully rescued for the RB of which 87% were resolved for genomic integration sequences. Our results demonstrate that the plasmid rescue approach can be used for resolving T-DNA integration sites in Laccaria. The RB was well conserved during transformation of this fungus and the integration analysis showed no clear sequence homology between different genomic sites. Neither obvious sequence similarities were found between these sites and the T-DNA borders indicating non-homologous integration of the transgenes. Majority (75%) of the integrations were located in predicted genes. Agrobacterium-mediated gene transfer is a powerful tool that can be used for functional gene studies in Laccaria and will be helpful along with plasmid rescue in searching for relevant fungal genes involved in the symbiotic process.
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Affiliation(s)
- Minna Kemppainen
- Laboratorio de Micología Molecular, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes. Roque Sáenz Peña 352, (B1876BXD) Bernal, Provincia de Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Sebastien Duplessis
- UMR 1136 INRA‐Université Henri Poincaré Nancy 1, Interactions Arbres/Micro‐organismes, Centre INRA de‐Nancy, F‐54280 Champenoux, France
| | - Francis Martin
- UMR 1136 INRA‐Université Henri Poincaré Nancy 1, Interactions Arbres/Micro‐organismes, Centre INRA de‐Nancy, F‐54280 Champenoux, France
| | - Alejandro G. Pardo
- Laboratorio de Micología Molecular, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes. Roque Sáenz Peña 352, (B1876BXD) Bernal, Provincia de Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
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Kemppainen M, Circosta A, Tagu D, Martin F, Pardo AG. Agrobacterium-mediated transformation of the ectomycorrhizal symbiont Laccaria bicolor S238N. Mycorrhiza 2005; 16:19-22. [PMID: 16133248 DOI: 10.1007/s00572-005-0008-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2004] [Revised: 05/26/2005] [Indexed: 05/04/2023]
Abstract
The development of an efficient transformation system is required to alter the expression of symbiosis-regulated genes and to develop insertional mutagenesis in the ectomycorrhizal basidiomycete Laccaria bicolor S238N. Vegetative mycelium of this fungus was transformed by Agrobacterium tumefaciens-mediated gene transfer. The selection marker was the hygromycin resistance gene of Escherichia coli (hph) under the control of the gpd promoter from Agaricus bisporus and the CaMV 35S terminator as part of the T-DNA. PCR amplification of hph and Southern blot analyses showed that the genome of the hygromycin-resistant transformants contained the cassette. The latter proved mostly single copy and random integration of part of the transgene into the fungal genome. A. tumefaciens-mediated gene transfer should facilitate future development of insertional mutagenesis, targeted gene disruption and RNA interference technology in L. bicolor.
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Affiliation(s)
- Minna Kemppainen
- Programa de Investigación en Interacciones Biológicas, Universidad Nacional de Quilmes, Roque Sáenz Peña 180, B1876BXD, Bernal, Provincia de Buenos Aires, Argentina
| | - Ariana Circosta
- Programa de Investigación en Interacciones Biológicas, Universidad Nacional de Quilmes, Roque Sáenz Peña 180, B1876BXD, Bernal, Provincia de Buenos Aires, Argentina
| | - Denis Tagu
- UMR INRA-UHP 1136 Interactions Arbres/Micro-organismes, Centre INRA de Nancy, 54280, Champenoux, France
- UMR BIO3P, Centre INRA de Rennes, BP 35327, 35653, Le Rheu Cedex, France
| | - Francis Martin
- UMR INRA-UHP 1136 Interactions Arbres/Micro-organismes, Centre INRA de Nancy, 54280, Champenoux, France
| | - Alejandro G Pardo
- Programa de Investigación en Interacciones Biológicas, Universidad Nacional de Quilmes, Roque Sáenz Peña 180, B1876BXD, Bernal, Provincia de Buenos Aires, Argentina.
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Pardo AG, Kemppainen M, Valdemoros D, Duplessis S, Martin F, Tagu D. T-DNA transfer from Agrobacterium tumefaciens to the ectomycorrhizal fungus Pisolithus microcarpus. Rev Argent Microbiol 2005; 37:69-72. [PMID: 16178458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023] Open
Abstract
The model ectomycorrhizal fungus Pisolithus microcarpus isolate 441 was transformed by using Agrobacterium tumefaciens LBA1100 and AGL-1. The selection marker was the Shble gene of Streptoallotecius hidustanus, conferring resistance to phleomycin, under the control of the gpd gene promoter and terminator of Schizophyllum commune. Transformation resulted in phleomycin resistant clones which were confirmed by PCR to contain the resistance cassette. A. tumefaciens-mediated gene transfer would allow the development of RNA interference technology in P. microcarpus.
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Affiliation(s)
- A G Pardo
- Programa de Investigación en Interacciones Biológicas, Universidad Nacional de Quilmes, Roque Sáenz Peña 180, (B1876BXD) Bernal, Provincia de Buenos Aires, Argentina.
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Gorfer M, Tarkka MT, Hanif M, Pardo AG, Laitiainen E, Raudaskoski M. Characterization of small GTPases Cdc42 and Rac and the relationship between Cdc42 and actin cytoskeleton in vegetative and ectomycorrhizal hyphae of Suillus bovinus. Mol Plant Microbe Interact 2001; 14:135-144. [PMID: 11204776 DOI: 10.1094/mpmi.2001.14.2.135] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
This work reports the isolation and molecular characterization of CDC42 and RAC1 cDNAs from the ectomycorrhiza forming filamentous homobasidiomycete Suillus bovinus. Previously, no RAC gene was described from filamentous fungi and no CDC42 gene was described from homobasidiomycetes. Southern hybridization with SbCDC42 and SbRAC1 cDNAs indicated that the S. bovinus genome contains only one CDC42 and one RAC1 gene. The predicted amino acid sequence of SbRaclp is 77% identical with the Rac1B protein of chick, whereas SbCdc42p is most identical with Schizosaccharomyces pombe Cdc42p, showing 88% identity. In the predicted amino acid sequences of SbRaclp and SbCdc42p, the five guanine nucleotide binding regions, switch I and II, and the effector domain are highly identical to those known in other small GTPases. These domain structures suggest that in S. bovinus, SbRac1p and SbCdc42p function as molecular switches regulating the organization of actin cytoskeleton, similar to yeasts and mammals. SbRAC1 and SbCDC42 were expressed in vegetative and ectomycorrhizal hyphae, and SbCdc42p was detected in ectomycorrhiza-forming hyphae if growth and differentiation of the symbiotic hyphae took place. Cdc42p and actin were localized at the tips of S. bovinus vegetative hyphae. Similar to yeast, in filamentous fungi Cdc42p may be necessary to maintain the actin cytoskeleton at hyphal tips, making the polarized growth of the hyphae possible. In developing ectomycorrhiza, Cdc42p and actin were visualized in association with plasma membrane in swollen cells typical to the symbiotic hyphae. The role of Cdc42p and actin in regulation of the growth pattern and morphogenesis of ectomycorrhizal hyphae is discussed.
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Affiliation(s)
- M Gorfer
- Department of Biosciences, University of Helsinki, Finland
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Pardo AG, Obertello M, Forchiassin F. Cellulose and xylan degrading enzymes in Thecotheus pelletieri. Rev Argent Microbiol 2000; 32:190-5. [PMID: 11149150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
The ability to produce cellulose and xylan degrading enzymes by different strains of Thecotheus pelletieri, in liquid synthetic media with cellulose and xylan as inducers, was compared. All the strains tested were able to grow and produce cellulases and xylanases, being the strain BAFC 2077 the best producer. Several cultural conditions were analysed in order to optimise enzyme production by strain 2077. Shaking cultures gave higher yields of cellulases and xylanases compared with stationary ones. Asparagine at 0.75 g N/L was the best nitrogen source in promoting enzyme production. The influence of different surfactants on enzyme production was studied. Tween 80 exhibited no effect on growth and enzyme production, whereas Tween 20 and Triton X-100 were inhibitory. By means of studies of variation of cellulose/xylan ratio in the culture medium we determined that cellulose and xylan induced cellulase and xylanase synthesis, being the specific substrates the most effective. The inducible behavior of cellulases and xylanases in T. pelletieri was determined by means of inhibition of protein synthesis by cycloheximide and ethidium bromide. Moreover, we found that glucose as well as xylose repressed cellulase and xylanase synthesis in T. pelletieri.
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Affiliation(s)
- A G Pardo
- Laboratorio de Micología Experimental, Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, 1428 Buenos Aires, Argentina.
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Pardo AG, Forchiassin F. Influence of temperature and pH on cellulase activity and stability in Nectria catalinensis. Rev Argent Microbiol 1999; 31:31-5. [PMID: 10327458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Abstract
The influence of temperature and pH on the activity and stability of the cellulase system (endoglucanase, exoglucanase and cellobiase) was investigated in Nectria catalinensis. Optimal temperature for the activity of the cellulase system ranged from 50 to 55 degrees C, with an optimum for stability between 23 degrees C and 37 degrees C after a 72 h incubation period. For the different enzymes, maximal activity was registered between pH 4.2-5.8, with pH 4.8 being close to optimal for all stability studies. The activation energy was 4.97 Kcal mol-1 for endoglucanase, 4.37 Kcal mol-1 for exoglucanase and 13.73 Kcal mol-1 for cellobiase. The K(m) and Vmax values were 1.73 mg CMC ml-1 and 0.45 mumol glucose min-1 mg protein-1 for endoglucanase, 0.22 mg microcrystalline cellulose ml-1 and 57.1 nmol glucose min-1 mg protein-1 for exoglucanase, and 2.95 mM cellobiose and 0.17 mumol glucose min-1 mg protein-1 for cellobiase.
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Affiliation(s)
- A G Pardo
- Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina.
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Pardo AG, Forchiassin F. Influence of different cultural conditions on cellulase production by Nectria catalinensis. Rev Argent Microbiol 1998; 30:20-9. [PMID: 9629604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The production of the extracellular cellulolytic enzyme system (endoglucanase, exoglucanase and cellobiase) of N. catalinensis was tested with different nitrogen sources, inorganic and organic ones, in liquid culture medium with microcrystalline cellulose. The nitrogen compounds used were: potassium nitrate, sodium nitrate, ammonium nitrate, ammonium phosphate, ammonium sulphate, ammonium chloride, ammonium carbonate, ammonium acetate, ammonium tartrate, urea, casamino acids, glycine, L-alanine, L-leucine, L-proline, L-lysine, L-aspartic acid, L-glutamic acid, L-asparagine, L-glutamine, L-phenylalanine, L-tyrosine, L-tryptophan, L-methionine and L-cysteine. Among these, ammonium nitrate and ammonium tartrate gave the highest yields of cellulases in 20-day-old cultures at a concentration equivalent to 0.75 g N/l in both cases. Optimal temperature for cellulase production, growth and cellulose degradation was 23 degrees C. On the other hand, an initial pH of 6.5 gave the highest yields of endoglucanase and cellobiase. In the same way, at pH 6.5, maximal growth and cellulose degradation were achieved. However, maximal exoglucanase production and glycogen content were reached at pH 7.5.
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Affiliation(s)
- A G Pardo
- Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina.
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26
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Pardo AG, Magnelli PE. [Endoglucanase induction in Nectria catalinenesis with various carbon sources]. Rev Argent Microbiol 1996; 28:182-9. [PMID: 9102659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The effect of different carbon sources on endoglucanase synthesis in Nectria catalinensis was investigated. Many different kinds of sugars (mono, di and polysaccharides) were added to the culture in order to investigate their effect on endoglucanase induction. The highest yield of cellulase was achieved with microcrystalline cellulose as the carbon source but the best inducer was CMC-Na because a very poor biomass amount was capable of producing the second yield of endoglucanase. On the other hand, glucose and cellobiose gave the highest yields of biomass.
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Affiliation(s)
- A G Pardo
- Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
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27
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Abstract
The effect of different nonionic surfactants (Tween 80, Tween 20, Triton X-100) and polyethylene glycol (PEG 6000) was tested on cellulolytic enzyme system production. Tween 80 gave the highest yield of endoglucanase, exoglucanase, and cellobiase at the 20th day of growth, presumably by causing increased permeability of cell membranes and/or by promoting the release of cell-bound enzymes. Maximal yield of endoglucanase was achieved with 1.7 mM Tween 80, whereas exoglucanase and cellobiase were at 0.85 mM. In the same way, this compound increased fungal growth. On the other hand, Tween 20 and Triton X-100 inhibited growth and cellulolytic enzyme production. High yields of endoglucanase and exoglucanase were achieved with PEG 6000 in comparison with the control, presumably by increasing enzyme stability.
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Affiliation(s)
- AG Pardo
- Laboratorio de Micologia Experimental, Departamento de Ciencias Biologicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon II 4degrees Piso, 1428-Buenos Aires, Argentine
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28
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Levin LN, Sívori AS, Pardo AG. [Cellulolytic activity of coprophilic fungi]. Rev Argent Microbiol 1996; 28:132-8. [PMID: 9026823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Fourteen isolates, members of the Ascobolaceae family, representing two widespread genera, Ascobolus and Saccobolus, were obtained from dung of herbivorous animals. All the isolates were capable of growing and producing clearing zones in CMC agar media. The species of Ascobolus gave larger clearing zones than the species of Saccobolus. S. verrucisporus and S. longevisporus were the most cellulolytic species in this genera while A. bistisii was the most cellulolytic among all the species tested. The results obtained showed that more than one method of screening must be employed to analyse the cellulolytic ability of different species.
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Affiliation(s)
- L N Levin
- Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
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Steiner LA, Pardo AG, Margolies MN. Amino acid sequence of the heavy-chain variable region of the crystallizable human myeloma protein Dob. Biochemistry 1979; 18:4068-80. [PMID: 114209 DOI: 10.1021/bi00586a003] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The amino acid sequence of the heavy-chain variable region of the crystallizable human myeloma protein Dob has been determined. This protein has previously been shown to have a deletion in the hinge region [Lopes, A. D., & Steiner, L. A. (1973) Fed. Proc., Fed. Am. Soc. Exp. Biol. 32, 1003; Steiner, L. A., & Lopes, A. D. (1979) Biochemistry (preceding paper in this issue)]. The complete sequence was established by analysis, in the automated sequenator, of the intact Fd' piece and of three large overlapping fragments prepared from Fd' by digestion with cyanogen bromide, by tryptic digestion of the citraconylated Fd', and by cleavage with hydroxylamine. Portions of the sequence were confirmed by examination of the amino acid composition and the partial sequence of a variety of small peptides obtained by enzymatic degradation. The Dob heavy-chain variable region appears to belong to the VHIII subgroup, but there are several unusual substitutions. Residue 45 in the Dob sequence is proline, although all other known heavy-chain sequences in man, mouse, rabbit, and guinea pig have leucine at this position. Positions 10 (aspartic acid), 68 (alanine), and 82 (leucine) in the Dob sequence are also atypical. There is no deleted segment in the variable region of the Dob heavy chain nor any abnormality in the variable-constant joining region. The hinge-region deletion appears to be the only gross structural anomaly in the Dob heavy chain.
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Pardo AG, Rosenwasser ES, Frangione B. The primary structure of a human immunoglobulin G2 (IgG2) pFc' fragment. J Immunol 1978; 121:1040-4. [PMID: 690433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Amino acid sequence analysis of the pFc' fragment obtained by pepsin digestion of a human IgG2 myeloma protein PIG Gm (n or 23) negative shows it to consist of 112 residues. It starts at position 334 (gamma1 numbering) and contains eight residues from the Cgamma2 region, and the whole Cgamma3 domain. Comparison with the sequence of gamma1 shows two differences at positions 339 and 397. Each of them can be explained by a single base substitution. This high degree of homology among gamma-chain subclasses suggests a recent diversification.
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