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Salih R, Brochu AS, Labbé C, Strelkov SE, Franke C, Bélanger R, Pérez-López E. A Hydroponic-Based Bioassay to Facilitate Plasmodiophora brassicae Phenotyping. Plant Dis 2024; 108:131-138. [PMID: 37536345 DOI: 10.1094/pdis-05-23-0959-re] [Citation(s) in RCA: 0] [Impact Index Per Article: 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] [Indexed: 08/05/2023]
Abstract
Clubroot, caused by the obligate parasite Plasmodiophora brassicae, is one of the most devastating diseases affecting the canola/oilseed rape (Brassica napus) industry worldwide. Currently, the planting of clubroot-resistant (CR) cultivars is the most effective strategy used to restrict the spread and the economic losses linked to the disease. However, virulent P. brassicae isolates have been able to infect many of the currently available CR cultivars, and the options to manage the disease are becoming limited. Another challenge has been achieving consistency in evaluating host reactions to P. brassicae infection, with most bioassays conducted in soil and/or potting medium, which requires significant space and can be labor intensive. Visual scoring of clubroot symptom development can also be influenced by user bias. Here, we have developed a hydroponic bioassay using well-characterized P. brassicae single-spore isolates representative of clubroot virulence in Canada, as well as field isolates from three Canadian provinces in combination with canola inbred homozygous lines carrying resistance genetics representative of CR cultivars available to growers in Canada. To improve the efficiency and consistency of disease assessment, symptom severity scores were compared with clubroot evaluations based on the scanned root area. According to the results, this bioassay offers a reliable, less expensive, and reproducible option to evaluate P. brassicae virulence, as well as to identify which canola resistance profile(s) may be effective against particular isolates. This bioassay will contribute to the breeding of new CR canola cultivars and the identification of virulence genes in P. brassicae that could trigger resistance and that have been very elusive to this day.[Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Rasha Salih
- Départment de Phytologie, Faculté des Sciences de l'Agriculture et de l'Alimentation, Université Laval, Quebec City, Quebec, Canada
- Centre de Recherche et d'Innovation sur les Végétaux (CRIV), Université Laval, Quebec City, Quebec, Canada
- Institute de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Quebec City, Quebec, Canada
| | - Anne-Sophie Brochu
- Départment de Phytologie, Faculté des Sciences de l'Agriculture et de l'Alimentation, Université Laval, Quebec City, Quebec, Canada
- Centre de Recherche et d'Innovation sur les Végétaux (CRIV), Université Laval, Quebec City, Quebec, Canada
- Institute de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Quebec City, Quebec, Canada
| | - Caroline Labbé
- Départment de Phytologie, Faculté des Sciences de l'Agriculture et de l'Alimentation, Université Laval, Quebec City, Quebec, Canada
- Centre de Recherche et d'Innovation sur les Végétaux (CRIV), Université Laval, Quebec City, Quebec, Canada
| | - Stephen E Strelkov
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada
| | - Coreen Franke
- Nutrien Ag Solutions Canada, Saskatoon, SK S4N 4L8, Canada
| | - Richard Bélanger
- Départment de Phytologie, Faculté des Sciences de l'Agriculture et de l'Alimentation, Université Laval, Quebec City, Quebec, Canada
- Centre de Recherche et d'Innovation sur les Végétaux (CRIV), Université Laval, Quebec City, Quebec, Canada
- Institute de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Quebec City, Quebec, Canada
| | - Edel Pérez-López
- Départment de Phytologie, Faculté des Sciences de l'Agriculture et de l'Alimentation, Université Laval, Quebec City, Quebec, Canada
- Centre de Recherche et d'Innovation sur les Végétaux (CRIV), Université Laval, Quebec City, Quebec, Canada
- Institute de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Quebec City, Quebec, Canada
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Santhanam P, Labbé C, Tremblay V, Bélanger RR. A rapid molecular diagnostic tool to discriminate alleles of avirulence genes and haplotypes of Phytophthora sojae using high-resolution melting analysis. Mol Plant Pathol 2024; 25:e13406. [PMID: 38009407 PMCID: PMC10799203 DOI: 10.1111/mpp.13406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 10/02/2023] [Accepted: 11/03/2023] [Indexed: 11/28/2023]
Abstract
Effectors encoded by avirulence genes (Avr) interact with the Phytophthora sojae resistance gene (Rps) products to generate incompatible interactions. The virulence profile of P. sojae is rapidly evolving as a result of the large-scale deployment of Rps genes in soybean. For a successful exploitation of Rps genes, it is recommended that soybean growers use cultivars containing the Rps genes corresponding to Avr genes present in P. sojae populations present in their fields. Determination of the virulence profile of P. sojae isolates is critical for the selection of soybean cultivars. High-resolution melting curve (HRM) analysis is a powerful tool, first applied in medicine, for detecting mutations with potential applications in different biological fields. Here, we report the development of an HRM protocol, as an original approach to discriminate effectors, to differentiate P. sojae haplotypes for six Avr genes. An HRM assay was performed on 24 P. sojae isolates with different haplotypes collected from soybean fields across Canada. The results clearly confirmed that the HRM assay discriminated different virulence genotypes. Moreover, the HRM assay was able to differentiate multiple haplotypes representing small allelic variations. HRM-based prediction was validated by phenotyping assays. This HRM assay provides a unique, cost-effective and efficient tool to predict virulence pathotypes associated with six different Avr (1b, 1c, 1d, 1k, 3a and 6) genes from P. sojae, which can be applied in the deployment of appropriate Rps genes in soybean fields.
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Affiliation(s)
- Parthasarathy Santhanam
- Département de PhytologieUniversité LavalQuebecQuebecCanada
- Present address:
Agriculture Agri‐Food Canada, MRDCMordenManitobaCanada
| | - Caroline Labbé
- Département de PhytologieUniversité LavalQuebecQuebecCanada
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Santhanam P, Madina MH, Albuini FM, Labbé C, Fietto LG, Bélanger RR. A unique effector secreted by Pseudozyma flocculosa mediates its biocontrol activity. BMC Biol 2023; 21:118. [PMID: 37226185 DOI: 10.1186/s12915-023-01624-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 05/10/2023] [Indexed: 05/26/2023] Open
Abstract
BACKGROUND Pseudozyma flocculosa is a highly efficient biocontrol agent (BCA) of powdery mildews whose mode of action remains elusive. It is known to secrete unique effectors during its interaction with powdery mildews but effectors have never been shown to be part of the arsenal of a BCA. Here, we characterize the role of the effector Pf2826 released by Pseudozyma flocculosa during its tripartite interaction with barley and the pathogen fungus Blumeria graminis f. sp. hordei. RESULTS We utilized CRISPR-Cas9-based genome editing and confirmed that secreted P. flocculosa effector Pf2826 is required for full biocontrol activity. We monitored the localization of the effector Pf2826 with C-terminal mCherry tag and found it localized around the haustoria and on powdery mildew spores. His-tagged Pf2826 recombinant protein was expressed, purified, and used as bait in a pull-down assay from total proteins extracted during the tripartite interaction. Potential interactors were identified by LC-MS/MS analysis after removing unspecific interactions found in the negative controls. A two-way yeast two-hybrid assay validated that Pf2826 interacted with barley pathogenesis-related (PR) proteins HvPR1a and chitinase and with an effector protein from powdery mildew. CONCLUSIONS In contrast to the usual modes of action of competition, parasitism, and antibiosis ascribed to BCAs, this study shows that effector pf2826 plays a vital role in the biocontrol activity of P. flocculosa by interacting with plant PR proteins and a powdery mildew effector, altering the host-pathogen interaction.
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Affiliation(s)
- Parthasarathy Santhanam
- Département de Phytologie, Université Laval, Québec, QC, Canada
- Present Address: Agriculture Agri-Food Canada, Morden, MB, Canada
| | - Mst Hur Madina
- Département de Phytologie, Université Laval, Québec, QC, Canada
| | - Fernanda Matias Albuini
- Département de Phytologie, Université Laval, Québec, QC, Canada
- Departamento de Bioquímica E Biologia Molecular, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Caroline Labbé
- Département de Phytologie, Université Laval, Québec, QC, Canada
| | - Luciano Gomes Fietto
- Departamento de Bioquímica E Biologia Molecular, Universidade Federal de Viçosa, Viçosa, MG, Brazil
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Flourieusse A, Bourgeois P, Schenckbecher E, Palvair J, Legrand D, Labbé C, Bescond T, Avoscan L, Orlowski S, Rouleau A, Frelet-Barrand A. Formation of intracellular vesicles within the Gram+ Lactococcus lactis induced by the overexpression of Caveolin-1β. Microb Cell Fact 2022; 21:239. [PMCID: PMC9670397 DOI: 10.1186/s12934-022-01944-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 10/02/2022] [Indexed: 11/18/2022] Open
Abstract
Abstract
Background
Caveolae are invaginated plasma membrane domains of 50–100 nm in diameter involved in many important physiological functions in eukaryotic cells. They are composed of different proteins, including the membrane-embedded caveolins and the peripheric cavins. Caveolin-1 has already been expressed in various expression systems (E. coli, insect cells, Toxoplasma gondii, cell-free system), generating intracellular caveolin-enriched vesicles in E. coli, insect cells and T. gondii. These systems helped to understand the protein insertion within the membrane and its oligomerization. There is still need for fundamental insights into the formation of specific domains on membrane, the deformation of a biological membrane driven by caveolin-1, the organization of a caveolar coat, and the requirement of specific lipids and proteins during the process. The aim of this study was to test whether the heterologously expressed caveolin-1β was able to induce the formation of intracellular vesicles within a Gram+ bacterium, Lactococcus lactis, since it displays a specific lipid composition different from E. coli and appears to emerge as a good alternative to E. coli for efficient overexpression of various membrane proteins.
Results
Recombinant bacteria transformed with the plasmid pNZ-HTC coding for the canine isoform of caveolin-1β were shown to produce caveolin-1β, in its functional oligomeric form, at a high expression level unexpected for an eukaryotic membrane protein. Electron microscopy revealed several intracellular vesicles from 30 to 60 nm, a size comparable to E. coli h-caveolae, beneath the plasma membrane of the overexpressing bacteria, showing that caveolin-1β is sufficient to induce membrane vesiculation. Immunolabelling studies showed antibodies on such neo-formed intracellular vesicles, but none on plasma membrane. Density gradient fractionation allowed the correlation between detection of oligomers on Western blot and appearance of vesicles measurable by DLS, showing the requirement of caveolin-1β oligomerization for vesicle formation.
Conclusions
Lactococcus lactis cells can heterologously overexpress caveolin-1β, generating caveolin-1β enriched intracellular neo-formed vesicles. These vesicles might be useful for potential co-expression of membrane proteins of pharmaceutical interest for their simplified functional characterization.
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Arsenault‐Labrecque G, Santhanam P, Asselin Y, Cinget B, Lebreton A, Labbé C, Belzile F, Gijzen M, Bélanger RR. RXLR effector gene Avr3a from Phytophthora sojae is recognized by Rps8 in soybean. Mol Plant Pathol 2022; 23:693-706. [PMID: 35150190 PMCID: PMC8995065 DOI: 10.1111/mpp.13190] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 01/15/2022] [Accepted: 01/17/2022] [Indexed: 06/14/2023]
Abstract
The use of resistance genes in elite soybean cultivars is one of the most widely used methods to manage Phytophthora sojae. This method relies on effector-triggered immunity, where a Resistant to P. sojae (Rps) gene product from the plant recognizes a specific effector from the pathogen, encoded by an avirulence (Avr) gene. Many Avr genes from P. sojae have been identified in the last decade, allowing a better exploitation of this type of resistance. The objective of the present study was to identify the Avr gene triggering immunity derived from the soybean resistance gene Rps8. The analysis of a segregating F2 progeny coupled with a genotyping-by-sequencing approach led to the identification of a putative Avr8 locus. The investigation of this locus using whole-genome sequencing data from 31 isolates of P. sojae identified Avr3a as the likely candidate for Avr8. Long-read sequencing also revealed that P. sojae isolates can carry up to five copies of the Avr3a gene, compared to the four previously reported. Haplotype and transcriptional analyses showed that amino acid changes and absence of Avr3a transcripts from P. sojae isolates caused changes in virulence towards Rps8. Functional analyses using CRISPR/Cas9 knockout and constitutive expression demonstrated that Rps8 interacted with Avr3a. We also showed that a specific allele of Avr3a is recognized by Rps3a but not Rps8. While Rps3a and Rps8 have been previously described as closely linked, this is the first report of a clear distinction hitherto undefined between these two resistance genes.
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Affiliation(s)
| | | | - Yanick Asselin
- Department of PhytologyUniversité LavalQuébecQuébecCanada
| | | | | | - Caroline Labbé
- Department of PhytologyUniversité LavalQuébecQuébecCanada
| | | | - Mark Gijzen
- Agriculture and Agri‐Food CanadaLondonOntarioCanada
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Belzile F, Jean M, Torkamaneh D, Tardivel A, Lemay MA, Boudhrioua C, Arsenault-Labrecque G, Dussault-Benoit C, Lebreton A, de Ronne M, Tremblay V, Labbé C, O’Donoughue L, St-Amour VTB, Copley T, Fortier E, Ste-Croix DT, Mimee B, Cober E, Rajcan I, Warkentin T, Gagnon É, Legay S, Auclair J, Bélanger R. The SoyaGen Project: Putting Genomics to Work for Soybean Breeders. Front Plant Sci 2022; 13:887553. [PMID: 35557742 PMCID: PMC9087807 DOI: 10.3389/fpls.2022.887553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 03/24/2022] [Indexed: 06/15/2023]
Abstract
The SoyaGen project was a collaborative endeavor involving Canadian soybean researchers and breeders from academia and the private sector as well as international collaborators. Its aims were to develop genomics-derived solutions to real-world challenges faced by breeders. Based on the needs expressed by the stakeholders, the research efforts were focused on maximizing realized yield through optimization of maturity and improved disease resistance. The main deliverables related to molecular breeding in soybean will be reviewed here. These include: (1) SNP datasets capturing the genetic diversity within cultivated soybean (both within a worldwide collection of > 1,000 soybean accessions and a subset of 102 short-season accessions (MG0 and earlier) directly relevant to this group); (2) SNP markers for selecting favorable alleles at key maturity genes as well as loci associated with increased resistance to key pathogens and pests (Phytophthora sojae, Heterodera glycines, Sclerotinia sclerotiorum); (3) diagnostic tools to facilitate the identification and mapping of specific pathotypes of P. sojae; and (4) a genomic prediction approach to identify the most promising combinations of parents. As a result of this fruitful collaboration, breeders have gained new tools and approaches to implement molecular, genomics-informed breeding strategies. We believe these tools and approaches are broadly applicable to soybean breeding efforts around the world.
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Affiliation(s)
- François Belzile
- Département de Phytologie, Université Laval, Quebec City, QC, Canada
| | - Martine Jean
- Département de Phytologie, Université Laval, Quebec City, QC, Canada
| | - Davoud Torkamaneh
- Département de Phytologie, Université Laval, Quebec City, QC, Canada
| | - Aurélie Tardivel
- Département de Phytologie, Université Laval, Quebec City, QC, Canada
- Centre de Recherche sur les Grains (CEROM), Saint-Mathieu-de-Beloeil, QC, Canada
| | - Marc-André Lemay
- Département de Phytologie, Université Laval, Quebec City, QC, Canada
| | - Chiheb Boudhrioua
- Département de Phytologie, Université Laval, Quebec City, QC, Canada
| | | | | | - Amandine Lebreton
- Département de Phytologie, Université Laval, Quebec City, QC, Canada
| | - Maxime de Ronne
- Département de Phytologie, Université Laval, Quebec City, QC, Canada
| | - Vanessa Tremblay
- Département de Phytologie, Université Laval, Quebec City, QC, Canada
| | - Caroline Labbé
- Département de Phytologie, Université Laval, Quebec City, QC, Canada
| | - Louise O’Donoughue
- Centre de Recherche sur les Grains (CEROM), Saint-Mathieu-de-Beloeil, QC, Canada
| | - Vincent-Thomas Boucher St-Amour
- Département de Phytologie, Université Laval, Quebec City, QC, Canada
- Centre de Recherche sur les Grains (CEROM), Saint-Mathieu-de-Beloeil, QC, Canada
| | - Tanya Copley
- Centre de Recherche sur les Grains (CEROM), Saint-Mathieu-de-Beloeil, QC, Canada
| | - Eric Fortier
- Centre de Recherche sur les Grains (CEROM), Saint-Mathieu-de-Beloeil, QC, Canada
| | | | - Benjamin Mimee
- Agriculture and Agri-Food Canada, St-Jean-sur-Richelieu, QC, Canada
| | - Elroy Cober
- Agriculture and Agri-Food Canada, Ottawa, ON, Canada
| | - Istvan Rajcan
- Department of Plant Agriculture, University of Guelph, Guelph, ON, Canada
| | - Tom Warkentin
- Department of Plant Sciences, University of Saskatchewan, Saskatoon, SK, Canada
| | - Éric Gagnon
- Semences Prograin Inc., Saint-Césaire, QC, Canada
- Sevita Genetics, Inkerman, ON, Canada
| | | | | | - Richard Bélanger
- Département de Phytologie, Université Laval, Quebec City, QC, Canada
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de Ronne M, Santhanam P, Cinget B, Labbé C, Lebreton A, Ye H, Vuong TD, Hu H, Valliyodan B, Edwards D, Nguyen HT, Belzile F, Bélanger R. Mapping of partial resistance to Phytophthora sojae in soybean PIs using whole-genome sequencing reveals a major QTL. Plant Genome 2022; 15:e20184. [PMID: 34964282 DOI: 10.1002/tpg2.20184] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 11/09/2021] [Indexed: 06/14/2023]
Abstract
In the last decade, more than 70 quantitative trait loci (QTL) related to soybean [Glycine max (L.) Merr.] partial resistance (PR) against Phytophthora sojae have been identified by genome-wide association studies (GWAS). However, most of them have either a minor effect on the resistance level or are specific to a single phenotypic variable or one isolate, thereby limiting their use in breeding programs. In this study, we have used an analytical approach combining (a) the phenotypic characterization of a diverse panel of 357 soybean accessions for resistance to P. sojae captured through a single variable, corrected dry weight; (b) a new hydroponic assay allowing the inoculation of a combination of P. sojae isolates covering the spectrum of commercially relevant Rps genes; and (c) exhaustive genotyping through whole-genome resequencing (WGS). This led to the identification of a novel P. sojae resistance QTL with a relatively major effect compared with the previously reported QTL. The QTL interval, spanning ∼500 kb on chromosome (Chr) 15, does not colocalize with previously reported QTL for P. sojae resistance. Plants carrying the favorable allele at this QTL were 60% more resistant. Eight genes were found to reside in the linkage disequilibrium (LD) block containing the peak single-nucleotide polymorphism (SNP) including Glyma.15G217100, which encodes a major latex protein (MLP)-like protein, with a functional annotation related to pathogen resistance. Expression analysis of Glyma.15G217100 indicated that it was nearly eight times more highly expressed in a group of plant introductions (PIs) carrying the resistant (R) allele compared with those carrying the susceptible (S) allele within a short period after inoculation. These results offer new and valuable options to develop improved soybean cultivars with broad resistance to P. sojae through marker-assisted selection.
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Affiliation(s)
| | | | | | | | | | - Heng Ye
- Division of Plant Sciences and National Center for Soybean Biotechnology, Univ. of Missouri, Columbia, MO, 65211, USA
| | - Tri D Vuong
- Division of Plant Sciences and National Center for Soybean Biotechnology, Univ. of Missouri, Columbia, MO, 65211, USA
| | - Haifei Hu
- School of Biological Sciences and Institute of Agriculture, Univ. of Western Australia, Perth, Western Australia, Australia
| | - Babu Valliyodan
- Division of Plant Sciences and National Center for Soybean Biotechnology, Univ. of Missouri, Columbia, MO, 65211, USA
- Dep. of Agriculture and Environmental Sciences, Lincoln Univ., Jefferson City, MO, 65101, USA
| | - David Edwards
- School of Biological Sciences and Institute of Agriculture, Univ. of Western Australia, Perth, Western Australia, Australia
| | - Henry T Nguyen
- Division of Plant Sciences and National Center for Soybean Biotechnology, Univ. of Missouri, Columbia, MO, 65211, USA
| | - François Belzile
- Dép. de phytologie, Univ. Laval, Québec, Canada
- Institut de Biologie Intégrative et des Systèmes (IBIS), Univ. Laval, Québec, Canada
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8
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Conti M, Cinget B, Labbé C, Asselin Y, Bélanger RR. New Insights into the Fungal Diversity of Cranberry Fruit Rot in Québec Farms Through a Large-Scale Molecular Analysis. Plant Dis 2022; 106:215-222. [PMID: 34515508 DOI: 10.1094/pdis-06-21-1163-re] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Cranberry fruit rot (CFR) pathogens are widely reported in the literature, but performing large-scale analysis of their presence inside fruit has always been challenging. In this study, a new molecular diagnostic tool, capable of identifying simultaneously 12 potential fungal species causing CFR, was used to better define the impact of CFR across cranberry fields in Québec. For this purpose, 126 fields and 7,825 fruits were sampled in three cranberry farms distributed throughout the province and subjected to comparative analyses of fungal presence and abundance according to cultural practices, sampling times, and cranberry cultivars. All 12 pathogens were detected throughout the study, but as a first major finding, the analyses revealed that four species, Godronia cassandrae, Colletotrichum fructivorum, Allantophomopsis cytisporea, and Coleophoma empetri, were consistently predominant regardless of the parameters studied. Comparison of conventional and organic productions showed a significant reduction in fungal richness and relative abundance. Interestingly, Monilinia oxycocci was found almost exclusively in organic productions, indicating that fungicides had a strong and persistent effect on its population. Surprisingly, there were no significant differences in fungal relative abundance or species richness between fruit sampled at harvest or in storage, suggesting that there may not exist a clear distinction between field and storage rot, as was previously thought. Comparative analysis of fungal species found on eight different cranberry cultivars indicated that they were all infected by the same fungi but could not rule out differences in genetic resistance. This large-scale analysis allows us to draw an exhaustive picture of CFR in Québec and provides new information with respect to its management.
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Affiliation(s)
- Matteo Conti
- Centre de Recherche en Innovation des Végétaux, Département de Phytologie, Université Laval, Québec G1V 0A6, Canada
| | - Benjamin Cinget
- Centre de Recherche en Innovation des Végétaux, Département de Phytologie, Université Laval, Québec G1V 0A6, Canada
| | - Caroline Labbé
- Centre de Recherche en Innovation des Végétaux, Département de Phytologie, Université Laval, Québec G1V 0A6, Canada
| | - Yanick Asselin
- Centre de Recherche en Innovation des Végétaux, Département de Phytologie, Université Laval, Québec G1V 0A6, Canada
| | - Richard R Bélanger
- Centre de Recherche en Innovation des Végétaux, Département de Phytologie, Université Laval, Québec G1V 0A6, Canada
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9
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Santhanam P, Labbé C, Fietto LG, Bélanger RR. A reassessment of flocculosin-mediated biocontrol activity of Pseudozyma flocculosa through CRISPR/Cas9 gene editing. Fungal Genet Biol 2021; 153:103573. [PMID: 34029708 DOI: 10.1016/j.fgb.2021.103573] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [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: 12/09/2020] [Revised: 03/17/2021] [Accepted: 05/10/2021] [Indexed: 11/26/2022]
Abstract
Pseudozyma flocculosa is an epiphytic yeast with powerful antagonistic activity against powdery mildews. This activity has been associated with the production of a rare antifungal glycolipid, flocculosin. In spite of the discovery of a specific gene cluster for flocculosin synthesis, attempts to ascribe a functional role to the molecule have been hampered by the inability to efficiently transform P. flocculosa. In this study, two different approaches, target gene replacement by homologous recombination (HR) and CRISPR-Cas9 based genome-editing, were utilized to decipher the role of flocculosin in the biocontrol activity of P.flocculosa. It was possible to alter the production of flocculosin through edition of fat1 by HR, but such mutants displayed abnormal phenotypes and the inability to produce sporidia. Sequencing analyses revealed that transformation by HR led to multiple insertions in the genome explaining the pleiotrophic effects of the approach. On the other hand, CRISPR-Cas9 transformation yielded one mutant that was altered specifically in the proper synthesis of flocculosin. Notwithstanding the loss of flocculosin production, such mutant was phenotypically similar to the wild-type, and when tested for its biocontrol activity against powdery mildew, displayed the same efficacy. These results offer strong evidence that flocculosin-mediated antibiosis is not responsible for the mode of action of P. flocculosa and highlight the potential of CRISPR-Cas9 for functional studies of otherwise difficult-to-transform fungi such as P. flocculosa.
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Affiliation(s)
| | - Caroline Labbé
- Département de Phytologie, Université Laval, Québec, QC, Canada
| | - Luciano Gomes Fietto
- Département de Phytologie, Université Laval, Québec, QC, Canada; Universidade Federal de Viçosa, Departamento de Bioquímica e Biologia Molecular, Viçosa, MG, Brazil
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10
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Rasoolizadeh A, Santhanam P, Labbé C, Shivaraj SM, Germain H, Bélanger RR. Silicon influences the localization and expression of Phytophthora sojae effectors in interaction with soybean. J Exp Bot 2020; 71:6844-6855. [PMID: 32090252 DOI: 10.1093/jxb/eraa101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [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: 01/17/2020] [Accepted: 02/23/2020] [Indexed: 06/10/2023]
Abstract
In plant-pathogen interactions, expression and localization of effectors in the aqueous apoplastic region play a crucial role in the establishment or suppression of pathogen development. Silicon (Si) has been shown to protect plants in several host-pathogen interactions, but its mode of action remains a source of debate. Its deposition in the apoplastic area of plant cells suggests that it might interfere with receptor-effector recognition. In this study, soybean plants treated or not with Si were inoculated with Phytophthora sojae and differences in the ensuing infection process were assessed through different microscopy techniques, transcript analysis of effector and defense genes, and effector (Avr6) localization through immunolocalization and fluorescence labeling. In plants grown without Si, the results showed the rapid (4 d post-inoculation) host recognition by P. sojae through the development of haustorium-like bodies, followed by expression and release of effectors into the apoplastic region. In contrast, Si treatment resulted in limited pathogen development, and significantly lower expression and presence of Avr6 in the apoplastic region. Based on immunolocalization and quantification of Avr6 through fluorescence labeling, our results suggest that the presence of Si in the apoplast interferes with host recognition and/or limits receptor-effector interactions, which leads to an incompatible interaction.
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Affiliation(s)
| | | | - Caroline Labbé
- Département de Phytologie, Université Laval, Québec City, Québec, Canada
| | | | - Hugo Germain
- Département de chimie, biochimie et physique, Université du Québec à Trois-Rivières, Trois-Rivières, Québec, Canada
| | - Richard R Bélanger
- Département de Phytologie, Université Laval, Québec City, Québec, Canada
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11
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Frieiro JL, Guillaume C, López-Vidrier J, Blázquez O, González-Torres S, Labbé C, Hernández S, Portier X, Garrido B. Toward RGB LEDs based on rare earth-doped ZnO. Nanotechnology 2020; 31:465207. [PMID: 32877372 DOI: 10.1088/1361-6528/abadc9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
By using ZnO thin films doped with Ce, Tb or Eu, deposited via radiofrequency magnetron sputtering, we have developed monochromatic (blue, green and red, respectively) light emitting devices (LEDs). The rare earth ions introduced with doping rates lower than 2% exhibit narrow and intense emission peaks due to electronic transitions in relaxation processes induced after electrical excitation. This study proves zinc oxide to be a good host for these elements, its high conductivity and optical transparency in the visible range being as well exploited as top transparent electrode. After structural characterization of the different doped layers, a device structure with intense electroluminescence is presented, modeled, and electrically and optically characterized. The different emission spectra obtained are compared in a chromatic diagram, providing a reference for future works with similar devices. The results hereby presented demonstrate three operating monochromatic LEDs, as well as a combination of the three species into another one, with a simply-designed structure compatible with current Si technology and demonstrating an integrated red-green-blue emission.
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Affiliation(s)
- J L Frieiro
- MIND, Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, Martí i Franquès 1, 08028, Barcelona, Spain. Institute of Nanoscience and Nanotechnology (IN²UB), Universitat de Barcelona, Barcelona 08028, Spain
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12
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de Ronne M, Labbé C, Lebreton A, Sonah H, Deshmukh R, Jean M, Belzile F, O’Donoughue L, Bélanger R. Integrated QTL mapping, gene expression and nucleotide variation analyses to investigate complex quantitative traits: a case study with the soybean-Phytophthora sojae interaction. Plant Biotechnol J 2020; 18:1492-1494. [PMID: 31749312 PMCID: PMC7292538 DOI: 10.1111/pbi.13301] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 10/10/2019] [Accepted: 11/05/2019] [Indexed: 05/31/2023]
Affiliation(s)
| | | | | | - Humira Sonah
- Département de phytologieUniversité LavalQuébecQCCanada
| | | | - Martine Jean
- Institut de Biologie Intégrative et des Systèmes (IBIS)Université LavalQuébecQCCanada
| | - François Belzile
- Institut de Biologie Intégrative et des Systèmes (IBIS)Université LavalQuébecQCCanada
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13
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Trost W, Labbé C, Grandjean D. Corrigendum to “Rhythmic entrainment as a musical affect induction mechanism”[Neuropsychologia 96 (2017) 96–110]. Neuropsychologia 2020; 136:107235. [DOI: 10.1016/j.neuropsychologia.2019.107235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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14
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Liang CH, An YT, Jin W, Meng DC, Wang DP, Chen CA, Liu KZ, Kleyn AW, Labbé C, Cardin J, Gourbilleau F. Correlation between composition, microstructure, and emission properties in Nd-doped Si-rich Si oxynitride films: investigation into the nature of the sensitizer. Nanotechnology 2019; 30:045702. [PMID: 30460927 DOI: 10.1088/1361-6528/aaea23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Rare earth (RE) ions doped in Si-based materials, compatible with Si technology, are promising compounds with regards to optical communication and energy conversion. In this article, we show the emission properties of Nd-doped Si-rich Si oxynitride (Nd-SRSON) films, and their dependence on the dangling bond density and the nature of the sensitizer. These films were prepared by reactive magnetron sputtering and post-annealing. The film composition, microstructure, and emission properties were investigated as a function of deposition parameters and annealing temperatures. Both Fourier transform infrared (FTIR) and ellipsometry spectroscopy measurements have confirmed that the sample composition (Si/N ratio) can be carefully tuned by varying the ratio of reactive nitrogen to argon in the sputtering plasma. Moreover, FTIR and x-ray photoelectron spectroscopy measurements demonstrate the existence of both nitrogen and oxygen dangling bonds (N· and O·) in as-deposited samples. These dangling bonds were passivated during annealing. Under non-resonant excitation at 488 nm, the films exhibit a significant photoluminescence (PL) signal from Nd3+ ions demonstrating the occurrence of an effective sensitization of Nd3+ ions in the host matrix. Both PL excitation and ellipsometry results (the energy band gap from new amorphous model) exclude the sensitization by an exciton with energy over the band gap, whereas the presence of Si agglomerates, at the atomic scale, have been identified as effective sensitizers towards Nd3+ ions. This work not only provides knowledge to optimize Si-based materials for favorable emission properties, but also, presents a universal methodology to investigate the nature of sensitizers for RE emitters. This allows one to find correlations between composition, microstructure, and emission properties.
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Affiliation(s)
- C-H Liang
- Institute of Materials, China Academy of Engineering Physics, 610200 Chengdu, Sichuan, People's Republic of China
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Rouillon C, Depincé A, Chenais N, Le Bail PY, Labbé C. 18 Characterisation of early embryonic cellular defects after somatic cell nuclear transfer in fish. Reprod Fertil Dev 2019. [DOI: 10.1071/rdv31n1ab18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Cryopreservation of genetic resources is of major interest for the security of biodiversity and the sustainability of the agronomic industry. Cryopreservation of somatic cells is one means of preserving the genome of both parents, but regeneration of functional breeders requires the mastering of somatic cell NT (SCNT). In mammals, SCNT consists of injecting the somatic nuclei into enucleated recipient oocytes to obtain clones that bear the genome of the donor. Cloning in fish presents some advantages over cloning in mammals: oocytes are produced by the hundreds, and development is external. Moreover, embryonic genome activation takes place after 10 mitoses only. These features are favourable to a better understanding of cellular reprogramming of the somatic cell. Nonenucleated oocytes are often used for SCNT, which allows the production of 2n clones bearing only the donor genome when the maternal chromatin is spontaneously removed by an unknown mechanism (25% of cases). This ability can help us understand the fate of the maternal chromatin and the role of its surrounding factors on the cellular behaviour of the somatic cell during the first developmental steps of embryonic development: meiosis resumption (MR) and mitosis. In this study, fin somatic cells and mature oocytes were obtained from a 2-year-old goldfish (Carassius auratus). For SCNT, the whole fin cell was injected into the sperm entry site, and the oocyte was activated by water contact after 30min to begin the development. Somatic and maternal chromatin behaviour during MR and early mitosis were characterised by immunofluorescence (Hoechst/Vybrant labelling for chromatin identification and α-tubulin for spindle organisation). Variability in chromatin condensation was observed after the somatic cell injection before the activation. Clone analysis (n=16) revealed that some of them presented a condensed somatic nuclei (71%) and others presented a decondensed nuclei (29%). After activation, most clones underwent normal polar body extrusion of the maternal chromatin (66%, n=69/95 clones v. 96%, n=96/100 controls oocytes) without extrusion of a somatic polar body. Afterward, clones that presented a first symmetric division (n=14/35) were analysed at the 2-cells stage and compared with fertilized embryos (n=7). The maternal chromatin was observed as fragmented on the cleavage furrow (79%), where it cannot contribute to the development. Spindle defects were observed in 50% of clone cells (v. 0% in controls), such as multicentrosomal spindles, chromosome misalignment, abnormal segregation, and DNA fragmentation. To conclude, those clone (2n or 3n) defects are probably due to the chromatin condensation observed before activation. The fish oocyte volume did not allow the MR of the condensed somatic chromatin, and that may induce an abnormal anaphase and the following clone developmental defects.
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Juergens RA, Mariano C, Jolivet J, Finn N, Rothenstein J, Reaume MN, Faghih A, Labbé C, Owen S, Shepherd FA, Villeneuve J, Romeyer F, Pettersson F, Butts C. Real-world benefit of nivolumab in a Canadian non-small-cell lung cancer cohort. ACTA ACUST UNITED AC 2018; 25:384-392. [PMID: 30607113 DOI: 10.3747/co.25.4287] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Background Nivolumab was the first immuno-oncology agent available for the treatment of lung cancer in Canada. In the present study, we evaluated the real-world benefit of nivolumab in Canadian patients with lung cancer. Methods Patients included in the cohort were identified from a registry of patients treated through expanded access to nivolumab before and after Health Canada approval. Demographics were collected from the application forms. Outcome data for the duration of treatment and survival were collected retrospectively. Results In contrast to the randomized clinical trial populations, our study cohort included patients who were older (median age: 66 years; range: 36-92 years) and who had an Eastern Cooperative Oncology Group performance status of 2 (8.9%). Despite the poorer-prognosis cohort, median overall survival was 12.0 months, which is comparable to the survival demonstrated in the randomized phase iii trials of nivolumab in lung cancer. Median time to treatment discontinuation was 3.45 months and was similar for all patient subgroups, including poorer-prognosis groups such as those with a performance status of 2, those 75 years of age and older, and those with brain metastases. Conclusions Nivolumab given in a real-world clinical setting was associated with results similar to those reported in the phase iii clinical trial setting.
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Affiliation(s)
| | - C Mariano
- Royal Columbian Hospital, New Westminster, BC
| | - J Jolivet
- Recherche médicale Saint-Jérôme Inc., Saint-Jérôme, QC
| | - N Finn
- Centre hospitalier universitaire Dr-Georges-L.-Dumont, Moncton, NB
| | - J Rothenstein
- R.S. McLaughlin Durham Regional Cancer Centre, Oshawa, ON
| | - M N Reaume
- The Ottawa Hospital Cancer Centre, Ottawa, ON
| | - A Faghih
- Thunder Bay Regional Health Sciences Centre, Thunder Bay, ON
| | - C Labbé
- Institut universitaire de cardiologie et de pneumologie de Québec, Quebec City, QC
| | - S Owen
- McGill University Health Centre, Montreal, QC
| | | | | | | | | | - C Butts
- Cross Cancer Institute, Edmonton, AB
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Arsenault-Labrecque G, Sonah H, Lebreton A, Labbé C, Marchand G, Xue A, Belzile F, Knaus BJ, Grünwald NJ, Bélanger RR. Stable predictive markers for Phytophthora sojae avirulence genes that impair infection of soybean uncovered by whole genome sequencing of 31 isolates. BMC Biol 2018; 16:80. [PMID: 30049268 PMCID: PMC6060493 DOI: 10.1186/s12915-018-0549-9] [Citation(s) in RCA: 18] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 07/19/2018] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND The interaction between oomycete plant pathogen Phytophthora sojae and soybean is characterized by the presence of avirulence (Avr) genes in P. sojae, which encode for effectors that trigger immune responses and resistance in soybean via corresponding resistance genes (Rps). A recent survey highlighted a rapid diversification of P. sojae Avr genes in soybean fields and the need to deploy new Rps genes. However, the full genetic diversity of P. sojae isolates remains complex and dynamic and is mostly characterized on the basis of phenotypic associations with differential soybean lines. RESULTS We sequenced the genomes of 31 isolates of P. sojae, representing a large spectrum of the pathotypes found in soybean fields, and compared all the genetic variations associated with seven Avr genes (1a, 1b, 1c, 1d, 1k, 3a, 6) and how the derived haplotypes matched reported phenotypes in 217 interactions. We discovered new variants, copy number variations and some discrepancies with the virulence of previously described isolates with Avr genes, notably with Avr1b and Avr1c. In addition, genomic signatures revealed 11.5% potentially erroneous phenotypes. When these interactions were re-phenotyped, and the Avr genes re-sequenced over time and analyzed for expression, our results showed that genomic signatures alone accurately predicted 99.5% of the interactions. CONCLUSIONS This comprehensive genomic analysis of seven Avr genes of P. sojae in a population of 31 isolates highlights that genomic signatures can be used as accurate predictors of phenotypes for compatibility with Rps genes in soybean. Our findings also show that spontaneous mutations, often speculated as a source of aberrant phenotypes, did not occur within the confines of our experiments and further suggest that epigenesis or gene silencing do not account alone for previous discordance between genotypes and phenotypes. Furthermore, on the basis of newly identified virulence patterns within Avr1c, our results offer an explanation why Rps1c has failed more rapidly in the field than the reported information on virulence pathotypes.
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Affiliation(s)
| | - Humira Sonah
- Département de Phytologie, Université Laval, Québec, QC Canada
| | | | - Caroline Labbé
- Département de Phytologie, Université Laval, Québec, QC Canada
| | | | - Allen Xue
- Agriculture and Agri-Food Canada, Ontario, ON Canada
| | | | - Brian J. Knaus
- Horticultural Crops Research Laboratory, USDA Agricultural Research Service, Corvallis, OR USA
| | - Niklaus J. Grünwald
- Horticultural Crops Research Laboratory, USDA Agricultural Research Service, Corvallis, OR USA
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18
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Rasoolizadeh A, Labbé C, Sonah H, Deshmukh RK, Belzile F, Menzies JG, Bélanger RR. Silicon protects soybean plants against Phytophthora sojae by interfering with effector-receptor expression. BMC Plant Biol 2018; 18:97. [PMID: 29848307 PMCID: PMC5977513 DOI: 10.1186/s12870-018-1312-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 05/15/2018] [Indexed: 05/07/2023]
Abstract
BACKGROUND Silicon (Si) is known to protect against biotrophic and hemibiotrophic plant pathogens; however, the mechanisms by which it exerts its prophylactic role remain unknown. In an attempt to obtain unique insights into the mode of action of Si, we conducted a full comparative transcriptomic analysis of soybean (Glycine max) plants and Phytophthora sojae, a hemibiotroph that relies heavily on effectors for its virulence. RESULTS Supplying Si to inoculated plants provided a strong protection against P. sojae over the course of the experiment (21 day). Our results showed that the response of Si-free (Si-) plants to inoculation was characterized early (4 dpi) by a high expression of defense-related genes, including plant receptors, which receded over time as the pathogen progressed into the roots. The infection was synchronized with a high expression of effectors by P. sojae, the nature of which changed over time. By contrast, the transcriptomic response of Si-fed (Si+) plants was remarkably unaffected by the presence of P. sojae, and the expression of effector-coding genes by the pathogen was significantly reduced. CONCLUSION Given that the apoplast is a key site of interaction between effectors and plant defenses and receptors in the soybean-P. sojae complex, as well as the site of amorphous-Si accumulation, our results indicate that Si likely interferes with the signaling network between P. sojae and the plant, preventing or decreasing the release of effectors reaching plant receptors, thus creating a form of incompatible interaction.
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Affiliation(s)
- Aliyeh Rasoolizadeh
- Département de Phytologie, Faculté des Sciences de l’Agriculture et de l’Alimentation, Université Laval, Québec City, Québec G1V 0A6 Canada
| | - Caroline Labbé
- Département de Phytologie, Faculté des Sciences de l’Agriculture et de l’Alimentation, Université Laval, Québec City, Québec G1V 0A6 Canada
| | - Humira Sonah
- Département de Phytologie, Faculté des Sciences de l’Agriculture et de l’Alimentation, Université Laval, Québec City, Québec G1V 0A6 Canada
| | - Rupesh K. Deshmukh
- Département de Phytologie, Faculté des Sciences de l’Agriculture et de l’Alimentation, Université Laval, Québec City, Québec G1V 0A6 Canada
| | - François Belzile
- Département de Phytologie and Institue de biologie intégrative et des systèmes, Université Laval, Québec City, Québec Canada
| | - James G. Menzies
- Agriculture and Agri-Food Canada, 101 Route 100, Morden, MB R6M 1Y5 Canada
| | - Richard R. Bélanger
- Département de Phytologie, Faculté des Sciences de l’Agriculture et de l’Alimentation, Université Laval, Québec City, Québec G1V 0A6 Canada
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Ehré F, Labbé C, Dufour C, Jadwisienczak WM, Weimmerskirch-Aubatin J, Portier X, Doualan JL, Cardin J, Richard AL, Ingram DC, Labrugère C, Gourbilleau F. The nitrogen concentration effect on Ce doped SiO xN y emission: towards optimized Ce 3+ for LED applications. Nanoscale 2018; 10:3823-3837. [PMID: 29412204 DOI: 10.1039/c7nr06139k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Ce-Doped SiOxNy films are deposited by magnetron reactive sputtering from a CeO2 target under a nitrogen reactive gas atmosphere. Visible photoluminescence measurements regarding the nitrogen gas flow reveal a large emission band centered at 450 nm for a sample deposited under a 2 sccm flow. Special attention is paid to the origin of such an emission at high nitrogen concentration. Different emitting centers are suggested in Ce doped SiOxNy films (e.g. band tails, CeO2, Ce clusters, Ce3+ ions), with different activation scenarios to explain the luminescence. X-ray photoelectron spectroscopy (XPS) reveals the exclusive presence of Ce3+ ions whatever the nitrogen or Ce concentrations, while transmission electron microscopy (TEM) shows no clusters or silicates upon high temperature annealing. With the help of photoluminescence excitation spectroscopy (PLE), a wide excitation range from 250 nm up to 400 nm is revealed and various excitations of Ce3+ ions are proposed involving direct or indirect mechanisms. Nitrogen concentration plays an important role in Ce3+ emission by modifying Ce surroundings, reducing the Si phase volume in SiOxNy and causing a nephelauxetic effect. Taking into account the optimized nitrogen growth parameters, the Ce concentration is analyzed as a new parameter. Under UV excitation, a strong emission is visible to the naked eye with high Ce3+ concentration (6 at%). No saturation of the photoluminescence intensity is observed, confirming again the lack of Ce cluster or silicate phase formation due to the nitrogen presence.
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Affiliation(s)
- F Ehré
- CIMAP, Normandie Univ, ENSICAEN, UNICAEN, CEA, CNRS, 14050 Caen, France.
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Laur J, Ramakrishnan GB, Labbé C, Lefebvre F, Spanu PD, Bélanger RR. Effectors involved in fungal-fungal interaction lead to a rare phenomenon of hyperbiotrophy in the tritrophic system biocontrol agent-powdery mildew-plant. New Phytol 2018; 217:713-725. [PMID: 29044534 PMCID: PMC6079639 DOI: 10.1111/nph.14851] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 09/13/2017] [Indexed: 05/08/2023]
Abstract
Tritrophic interactions involving a biocontrol agent, a pathogen and a plant have been analyzed predominantly from the perspective of the biocontrol agent. We have conducted the first comprehensive transcriptomic analysis of all three organisms in an effort to understand the elusive properties of Pseudozyma flocculosa in the context of its biocontrol activity against Blumeria graminis f.sp. hordei as it parasitizes Hordeum vulgare. After inoculation of P. flocculosa, the tripartite interaction was monitored over time and samples collected for scanning electron microscopy and RNA sequencing. Based on our observations, P. flocculosa indirectly parasitizes barley, albeit transiently, by diverting nutrients extracted by B. graminis from barley leaves through a process involving unique effectors. This brings novel evidence that such molecules can also influence fungal-fungal interactions. Their release is synchronized with a higher expression of powdery mildew haustorial effectors, a sharp decline in the photosynthetic machinery of barley and a developmental peak in P. flocculosa. The interaction culminates with a collapse of B. graminis haustoria, thereby stopping P. flocculosa growth, as barley plants show higher metabolic activity. To conclude, our study has uncovered a complex and intricate phenomenon, described here as hyperbiotrophy, only achievable through the conjugated action of the three protagonists.
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Affiliation(s)
- Joan Laur
- Département de PhytologieUniversité LavalQuébecQCCanadaG1V 0A6
| | | | - Caroline Labbé
- Département de PhytologieUniversité LavalQuébecQCCanadaG1V 0A6
| | | | - Pietro D. Spanu
- Department of Life SciencesImperial College LondonSouth Kensington CampusLondonSW7 2AZUK
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Lebreton A, Labbé C, De Ronne M, Xue AG, Marchand G, Bélanger RR. Development of a Simple Hydroponic Assay to Study Vertical and Horizontal Resistance of Soybean and Pathotypes of Phytophthora sojae. Plant Dis 2018; 102:114-123. [PMID: 30673456 DOI: 10.1094/pdis-04-17-0586-re] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Phytophthora root rot, caused by Phytophthora sojae, is one of the most damaging diseases of soybean and the introgression of Rps (Resistance to P. sojae) genes into elite soybean lines is arguably the best way to manage this disease. Current bioassays to phenotype the gene-for-gene relationship are hampered with respect to reproducibility and long-term stability of isolates, and do not accurately predict horizontal resistance individually. The aim of our study was to investigate a new way of phenotyping P. sojae isolates and vertical and horizontal resistance in soybean that relies on zoospores inoculated directly into a hydroponic system. Inoculation of P. sojae isolates against a set of eight differentials accurately and reproducibly identified pathotypes over a period of two years. When applied to test vertical resistance of soybean lines with known and unknown Rps genes, the bioassay relied on plant dry weight to correctly identify all genes. In addition, simultaneous inoculations of three P. sojae isolates, collectively carrying eight major virulence factors against 64 soybean lines with known and unknown levels of horizontal resistance, separated the plants into five distinct groups of root rot, allowing the discrimination of lines with various degrees of partial resistance. Based on those results, this bioassay offers several advantages in facilitating efforts in breeding soybean for P. sojae resistance and in identifying virulence factors in P. sojae.
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Affiliation(s)
- A Lebreton
- Département de Phytologie, Université Laval, Québec, Québec, G1V 0A6, Canada
| | - C Labbé
- Département de Phytologie, Université Laval, Québec, Québec, G1V 0A6, Canada
| | - M De Ronne
- Département de Phytologie, Université Laval, Québec, Québec, G1V 0A6, Canada
| | - A G Xue
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, Ottawa, Ontario K1A 0C6, Canada
| | - G Marchand
- Harrow Research and Development Centre, Agriculture and Agri-Food Canada, Harrow, Ontario N0R 1G0, Canada
| | - R R Bélanger
- Département de Phytologie, Université Laval, Québec, Québec, G1V 0A6, Canada
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Labbé C, Anderson M, Simard S, Tremblay L, Laberge F, Vaillancourt R, Lacasse Y. Wait times for diagnosis and treatment of lung cancer: a single-centre experience. ACTA ACUST UNITED AC 2017; 24:367-373. [PMID: 29270048 DOI: 10.3747/co.24.3655] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Background Multiple clinical practice guidelines recommend rapid evaluation of patients with suspected lung cancer. It is uncertain whether delays in diagnosis and management have a negative effect on outcomes. Methods This retrospective study included 551 patients diagnosed with lung cancer through the diagnostic assessment program at the Institut universitaire de cardiologie et de pneumologie de Québec between September 2013 and March 2015. Median wait times between initial referral, diagnosis, and first treatment were calculated and compared with recommended targets. Analyses were performed to evaluate for specific factors associated with longer wait times and for the effect of delays on the outcomes of progression-free survival (pfs), relapse-free survival (rfs) after primary surgical resection, and overall survival (os). Results Most patients were investigated and treated within recommended targets. Of the entire cohort, 379 patients were treated at our institution. Of those 379 patients, 311 (82%) were treated within recommended targets. In comparing patients within and outside target times, the only statistically significant difference was found in the distribution of treatment modalities: patients meeting targets were more likely to be treated with surgery or chemotherapy rather than with radiation. The pfs on first treatment modality was influenced by clinical stage, but not by time to therapy [hazard ratio (hr): 1.10; p = 0.65]. The os for the entire cohort was also influenced by stage, but not by delays (hr: 1.04; p = 0.87). For the 209 patients treated by surgery with curative intent, a significant reduction in rfs was associated with male sex and TNM stage, but not with delays (hr: 1.11; p = 0.83). The os after primary surgical resection was also associated with TNM stage, but not with delays (hr: 1.82; p = 0.43). Conclusions Recommended targets for wait times in the investigation and treatment of lung cancer can be achieved within a diagnostic assessment program. Compared with radiation treatment, treatment with surgery or chemotherapy is more likely to be completed within targets. Delays in investigation and treatment do not appear to negatively affect the clinical outcomes of os, rfs, and pfs. Prospective studies are needed to evaluate whether efficient work-up and treatment influence other important variables, such as quality of life, cost of care, and access to therapies while performance status is adequate.
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Affiliation(s)
| | | | | | | | | | - R Vaillancourt
- Centre multidisciplinaire de pneumologie et de chirurgie thoracique, Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Québec, QC
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Bourdages-Pageau E, Vieira A, Labbé C, Ugalde Figueroa P. P2.05-019 Overall Survival (OS) of Pathological T1N0 Non-Small Cell Lung Cancer (NSCLC) After Resection. J Thorac Oncol 2017. [DOI: 10.1016/j.jtho.2017.11.046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Sonah H, Deshmukh RK, Labbé C, Bélanger RR. Analysis of aquaporins in Brassicaceae species reveals high-level of conservation and dynamic role against biotic and abiotic stress in canola. Sci Rep 2017; 7:2771. [PMID: 28584277 PMCID: PMC5459863 DOI: 10.1038/s41598-017-02877-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [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] [Received: 01/05/2017] [Accepted: 04/19/2017] [Indexed: 01/11/2023] Open
Abstract
Aquaporins (AQPs) are of vital importance in the cellular transport system of all living organisms. In this study, genome-wide identification, distribution, and characterization of AQPs were determined in Arabidopsis lyrata, Capsella grandiflora, C. rubella, Eutrema salsugineum, Brassica rapa, B. oleracea, and B. napus (canola). Classification and phylogeny of AQPs revealed the loss of XIPs and NIP-IIIs in all species. Characterization of distinctive AQP features showed a high level of conservation in spacing between NPA-domains, and selectivity filters. Interestingly, TIP3s were found to be highly expressed in developing seeds, suggesting their role in seed desiccation. Analysis of available RNA-seq data obtained under biotic and abiotic stresses led to the identification of AQPs involved in stress tolerance mechanisms in canola. In addition, analysis of the effect of ploidy level, and resulting gene dose effect performed with the different combinations of Brassica A and C genomes revealed that more than 70% of AQPs expression were dose-independent, thereby supporting their role in stress alleviation. This first in-depth characterization of Brassicaceae AQPs highlights transport mechanisms and related physiological processes that could be exploited in breeding programs of stress-tolerant cultivars.
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Affiliation(s)
- Humira Sonah
- Département de phytologie-Faculté des Sciences de l'agriculture et de l'alimentation, Université Laval, Québec City, QC, Canada
| | - Rupesh K Deshmukh
- Département de phytologie-Faculté des Sciences de l'agriculture et de l'alimentation, Université Laval, Québec City, QC, Canada
| | - Caroline Labbé
- Département de phytologie-Faculté des Sciences de l'agriculture et de l'alimentation, Université Laval, Québec City, QC, Canada
| | - Richard R Bélanger
- Département de phytologie-Faculté des Sciences de l'agriculture et de l'alimentation, Université Laval, Québec City, QC, Canada.
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Labbé C, An YT, Zatryb G, Portier X, Podhorodecki A, Marie P, Frilay C, Cardin J, Gourbilleau F. Structural and emission properties of Tb 3+-doped nitrogen-rich silicon oxynitride films. Nanotechnology 2017; 28:115710. [PMID: 28140358 DOI: 10.1088/1361-6528/aa5ca0] [Citation(s) in RCA: 3] [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: 06/06/2023]
Abstract
Terbium doped silicon oxynitride host matrix is suitable for various applications such as light emitters compatible with CMOS technology or frequency converter systems for photovoltaic cells. In this study, amorphous Tb3+ ion doped nitrogen-rich silicon oxynitride (NRSON) thin films were fabricated using a reactive magnetron co-sputtering method, with various N2 flows and annealing conditions, in order to study their structural and emission properties. Rutherford backscattering (RBS) measurements and refractive index values confirmed the silicon oxynitride nature of the films. An electron microscopy analysis conducted for different annealing temperatures (T A) was also performed up to 1200 °C. Transmission electron microscopy (TEM) images revealed two different sublayers. The top layer showed porosities coming from a degassing of oxygen during deposition and annealing, while in the region close to the substrate, a multilayer-like structure of SiO2 and Si3N4 phases appeared, involving a spinodal decomposition. Upon a 1200 °C annealing treatment, a significant density of Tb clusters was detected, indicating a higher thermal threshold of rare earth (RE) clusterization in comparison to the silicon oxide matrix. With an opposite variation of the N2 flow during the deposition, the nitrogen excess parameter (Nex) estimated by RBS measurements was introduced to investigate the Fourier transform infrared (FTIR) spectrum behavior and emission properties. Different vibration modes of the Si-N and Si-O bonds have been carefully identified from the FTIR spectra characterizing such host matrices, especially the 'out-of-phase' stretching vibration mode of the Si-O bond. The highest Tb3+ photoluminescence (PL) intensity was obtained by optimizing the N incorporation and the annealing conditions. In addition, according to these conditions, the integrated PL intensity variation confirmed that the silicon nitride-based host matrix had a higher thermal threshold of rare earth clusterization than its silicon oxide counterpart. Analysis of time-resolved PL intensity versus T A showed the impact of Tb clustering on decay times, in agreement with the TEM observations. Finally, PL and PL excitation (PLE) experiments and comparison of the related spectra between undoped and Tb-doped samples were carried out to investigate the impact of the band tails on the excitation mechanism of Tb3+ ions.
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Affiliation(s)
- C Labbé
- CIMAP, Normandie Univ, ENSICAEN, UNICAEN, CEA, CNRS, 6 Boulevard Maréchal Juin 14050 Caen Cedex 4, France
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Ouellette S, Goyette MH, Labbé C, Laur J, Gaudreau L, Gosselin A, Dorais M, Deshmukh RK, Bélanger RR. Silicon Transporters and Effects of Silicon Amendments in Strawberry under High Tunnel and Field Conditions. Front Plant Sci 2017; 8:949. [PMID: 28642768 PMCID: PMC5462948 DOI: 10.3389/fpls.2017.00949] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Together with longer production periods, the commercial transition to day-neutral strawberry (Fragaria × ananassa) varieties has favored the development of diseases such as powdery mildew (Podosphaera aphanis) that thrives in late summer-early fall. In an attempt to find alternative solutions to fungicides currently employed to curb the disease, we wanted to investigate the potential of silicon (Si) amendments that have been associated with prophylactic properties against powdery mildews. To this end, our first objective was to determine if strawberry was a Si-competent species following the recent characterization of the properties of Si transporters that plants must carry to uptake silicic acid. Based on genomic data, we were able to conclude that strawberry contained both functional influx (Lsi1) and efflux (Lsi2) transporters for Si uptake. Subsequently commercial experiments under high tunnel and field conditions were conducted with different Si fertilization regimes: constant soluble Si feeding in high tunnel, and bi-weekly soluble Si feeding or three concentrations of calcium silicate fertilization in the field. Results from high tunnel experiments showed that strawberry could accumulate as much as 3% Si on a dry-weight basis, the highest concentration ever reported for this species. All six tested cultivars contained roughly the same concentration, thereby confirming the limited genetic variability, also observed in other species, associated with the trait. Silicon fertilization under high tunnel led to a significant reduction of powdery mildew severity in both years and on all cultivars, and a significant increase in yield of marketable fruits reaching as much as 300% with cv. Monterey. By contrast, Si fertilization under field conditions in soils deficient in plant available Si, either in soluble or solid form, did not result in significant accumulation of Si in plants, regardless of the cultivars, year or concentrations. Our results have thus provided both genotypic and phenotypic proof that strawberry can greatly benefit from Si fertilization, but have also highlighted the importance of validating the fertilization regime to ensure that Si is properly absorbed and/or available to the plant.
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Villeneuve L, Thivolet A, Bakrin N, Mohamed F, Isaac S, Valette PJ, Glehen O, Rousset P, Abba J, Abboud K, Arvieux C, Balagué G, Barrau V, Rejeb H, Bereder JM, Bibeau F, Bouzard D, Brigand C, Carrère S, Carretier M, de Chaisemartin C, Chassang M, Chevallier A, Courvoisier T, Dartigues P, Delroeux D, Desolneux G, Dohan A, Dromain C, Dumont F, Durand-Fontanier S, Elias D, Eveno C, Evrard S, Fay O, Ferron G, Geffroy D, Gilly FN, Fontaine J, Goasguen N, Ghouti L, Goéré D, Guilloit JM, Guyon F, Heyd B, Kaci R, Karoui M, Kianmanesh R, Labbé C, Lacroix J, Lang-Averous G, Laverriere MH, Lefevre J, Lelong B, Leroux A, Dico R, Loi V, Lorimier G, Marchal F, Mariani A, Mariani P, Mariette C, Meeus P, Mery E, Messager M, Msika S, Nadeau C, Ortega-Deballon P, Passot G, Petorin C, Peyrat P, Pezet D, Piessen G, Pirro N, Pocard M, Poizat F, Porcheron J, Pourcher G, Quenet F, Rat P, Regimbeau JM, Rousselot P, Sabbagh C, Svrcek M, Tetreau R, Thibaudeau E, Tuech JJ, Valmary-Degano S, Vaudoyer D, Velasco S, Verriele-Beurrier V, Wernert R, Zinzindohoue F. A new internet tool to report peritoneal malignancy extent. PeRitOneal MalIgnancy Stage Evaluation (PROMISE) application. Eur J Surg Oncol 2016; 42:877-82. [DOI: 10.1016/j.ejso.2016.03.015] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Revised: 03/12/2016] [Accepted: 03/16/2016] [Indexed: 11/17/2022] Open
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Labbé C, Tremblay L, Lacasse Y. Pericardiocentesis versus pericardiotomy for malignant pericardial effusion: a retrospective comparison. ACTA ACUST UNITED AC 2015; 22:412-6. [PMID: 26715874 DOI: 10.3747/co.22.2698] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Treatment of malignant pericardial effusion remains controversial, because no randomized controlled trials have been conducted to determine the best approach, and results of retrospective studies have been inconsistent. The objective of the present study was to compare pericardiocentesis and pericardiotomy with respect to efficacy for preventing recurrence, and to determine, for those two procedures, diagnostic yields, complication rates, and effects on survival. We also aimed to identify clinical and procedural factors that could predict effusion recurrence. METHODS We retrospectively assessed 61 patients who underwent a procedure for treatment of a malignant pericardial effusion at the Institut universitaire de cardiologie et de pneumologie de Québec between February 2004 and September 2013. RESULTS Pericardiocentesis was performed in 42 patients, and pericardiotomy, in 19 patients. The effusion recurrence rate was significantly higher in patients treated with pericardiocentesis than with pericardiotomy (31.0% vs. 5.3%, p = 0.046). The diagnostic yield of the procedures was not significantly different (92.9% vs. 86.7%, p = 0.6). The overall rate of complications was similar in the two groups, as was the median overall survival (2.4 months vs. 2.6 months, p = 0.5). In univariate analyses, the procedure type was the only predictor of recurrence that approached statistical significance. Age, sex, type of cancer, presence of effusion at the time of cancer diagnosis, prior chest irradiation, tamponade upon presentation, and total volume of fluid removed did not influence the recurrence rate. CONCLUSIONS Compared with pericardiocentesis, pericardiotomy had higher success rate in preventing recurrence of malignant pericardial effusion, with similar diagnostic yields, complication rates, and overall survival.
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Affiliation(s)
- C Labbé
- Centre de recherche, Centre de pneumologie, Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC
| | - L Tremblay
- Centre de recherche, Centre de pneumologie, Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC
| | - Y Lacasse
- Centre de recherche, Centre de pneumologie, Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC
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Vivancos J, Labbé C, Menzies JG, Bélanger RR. Silicon-mediated resistance of Arabidopsis against powdery mildew involves mechanisms other than the salicylic acid (SA)-dependent defence pathway. Mol Plant Pathol 2015; 16:572-82. [PMID: 25346281 PMCID: PMC6638373 DOI: 10.1111/mpp.12213] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
On absorption by plants, silicon (Si) offers protection against many fungal pathogens, including powdery mildews. The mechanisms by which Si exerts its prophylactic role remain enigmatic, although a prevailing hypothesis suggests that Si positively influences priming. Attempts to decipher Si properties have been limited to plants able to absorb Si, which excludes the model plant Arabidopsis because it lacks Si influx transporters. In this work, we were able to engineer Arabidopsis plants with an Si transporter from wheat (TaLsi1) and to exploit mutants (pad4 and sid2) deficient in salicylic acid (SA)-dependent defence responses to study their phenotypic response and changes in defence expression against Golovinomyces cichoracearum (Gc) following Si treatment. Our results showed that TaLsi1 plants contained significantly more Si and were significantly more resistant to Gc infection than control plants when treated with Si, the first such demonstration in a plant transformed with a heterologous Si transporter. The resistant plants accumulated higher levels of SA and expressed higher levels of transcripts encoding defence genes, thus suggesting a role for Si in the process. However, TaLsi1 pad4 and TaLsi1 sid2 plants were also more resistant to Gc than were pad4 and sid2 plants following Si treatment. Analysis of the resistant phenotypes revealed a significantly reduced production of SA and expression of defence genes comparable with susceptible controls. These results indicate that Si contributes to Arabidopsis defence priming following pathogen infection, but highlight that Si will confer protection even when priming is altered. We conclude that Si-mediated protection involves mechanisms other than SA-dependent defence responses.
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Affiliation(s)
- Julien Vivancos
- Département de Phytologie, Faculté des Sciences de l'Agriculture et de l'Alimentation, Université Laval, Québec, QC, Canada, G1V 0A6
| | - Caroline Labbé
- Département de Phytologie, Faculté des Sciences de l'Agriculture et de l'Alimentation, Université Laval, Québec, QC, Canada, G1V 0A6
| | - James G Menzies
- Agriculture and Agri-Food Canada, 101 Route 100, Morden, MB, Canada, R6M 1Y5
| | - Richard R Bélanger
- Département de Phytologie, Faculté des Sciences de l'Agriculture et de l'Alimentation, Université Laval, Québec, QC, Canada, G1V 0A6
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Deshmukh RK, Vivancos J, Ramakrishnan G, Guérin V, Carpentier G, Sonah H, Labbé C, Isenring P, Belzile FJ, Bélanger RR. A precise spacing between the NPA domains of aquaporins is essential for silicon permeability in plants. Plant J 2015; 83:489-500. [PMID: 26095507 DOI: 10.1111/tpj.12904] [Citation(s) in RCA: 128] [Impact Index Per Article: 14.2] [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: 03/13/2015] [Revised: 05/15/2015] [Accepted: 06/01/2015] [Indexed: 05/18/2023]
Abstract
The controversy surrounding silicon (Si) benefits and essentiality in plants is exacerbated by the differential ability of species to absorb this element. This property is seemingly enhanced in species carrying specific nodulin 26-like intrinsic proteins (NIPs), a subclass of aquaporins. In this work, our aim was to characterize plant aquaporins to define the features that confer Si permeability. Through comparative analysis of 985 aquaporins in 25 species with differing abilities to absorb Si, we were able to predict 30 Si transporters and discovered that Si absorption is exclusively confined to species that possess NIP-III aquaporins with a GSGR selectivity filter and a precise distance of 108 amino acids (AA) between the asparagine-proline-alanine (NPA) domains. The latter feature is of particular significance since it had never been reported to be essential for Si selectivity. Functionality assessed in the Xenopus oocyte expression system showed that NIPs with 108 AA spacing exhibited Si permeability, while proteins differing in that distance did not. In subsequent functional studies, a Si transporter from poplar mutated into variants with 109- or 107-AA spacing failed to import, and a tomato NIP gene mutated from 109 to 108 AA exhibited a rare gain of function. These results provide a precise molecular basis to classify higher plants into Si accumulators or excluders.
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Affiliation(s)
- Rupesh Kailasrao Deshmukh
- Département de Phytologie, Faculté des Sciences de l'Agriculture et de l'Alimentation, Centre de Recherche en Horticulture, Université Laval, Québec, QC, Canada
| | - Julien Vivancos
- Département de Phytologie, Faculté des Sciences de l'Agriculture et de l'Alimentation, Centre de Recherche en Horticulture, Université Laval, Québec, QC, Canada
| | - Gowsica Ramakrishnan
- Département de Phytologie, Faculté des Sciences de l'Agriculture et de l'Alimentation, Centre de Recherche en Horticulture, Université Laval, Québec, QC, Canada
| | - Valérie Guérin
- Département de Phytologie, Faculté des Sciences de l'Agriculture et de l'Alimentation, Centre de Recherche en Horticulture, Université Laval, Québec, QC, Canada
| | - Gabriel Carpentier
- Nephrology Group, L'Hôtel-Dieu de Québec Institution, Department of Medicine, Faculty of Medicine, Université Laval, Québec, QC, G1R 2J6, Canada
| | - Humira Sonah
- Département de Phytologie, Faculté des Sciences de l'Agriculture et de l'Alimentation, Centre de Recherche en Horticulture, Université Laval, Québec, QC, Canada
| | - Caroline Labbé
- Département de Phytologie, Faculté des Sciences de l'Agriculture et de l'Alimentation, Centre de Recherche en Horticulture, Université Laval, Québec, QC, Canada
| | - Paul Isenring
- Nephrology Group, L'Hôtel-Dieu de Québec Institution, Department of Medicine, Faculty of Medicine, Université Laval, Québec, QC, G1R 2J6, Canada
| | - Francois J Belzile
- Département de Phytologie, Faculté des Sciences de l'Agriculture et de l'Alimentation, Centre de Recherche en Horticulture, Université Laval, Québec, QC, Canada
| | - Richard R Bélanger
- Département de Phytologie, Faculté des Sciences de l'Agriculture et de l'Alimentation, Centre de Recherche en Horticulture, Université Laval, Québec, QC, Canada
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Mutelet B, Boudin S, Pérez O, Rueff JM, Labbé C, Jaffrès PA. La1-xLnxH(O3PCH3)2 (Ln = Tb, Eu; 0 < x ≤ 1): an organic-inorganic hybrid with lanthanide chains and tunable luminescence properties. Dalton Trans 2015; 44:1186-92. [PMID: 25412907 DOI: 10.1039/c4dt02643h] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The organic/inorganic La1-xLnxH(O3PCH3)2 (Ln = Eu, Tb) hybrids have been synthesized by hydrothermal synthesis. The crystal structure of LaH(O3PCH3)2 consists of chains of edge-sharing LaO8 polyhedra linked through PO3C tetrahedra. Photoluminescence of Eu(3+), Tb(3+) and Eu(3+)/Tb(3+) co-doped materials have been investigated. The Eu and Tb hybrids show no concentration quenching versus doping rate suggesting energy migration through a percolation model. The Eu hybrids exhibit a red emission while the Tb ones exhibit, with the Tb rate increasing, a blue to green emission under a 378 nm excitation wavelength and a cyan to green emission under a 262 nm excitation wavelength. The doping rate dependent red shift results from a cross relaxation phenomenon between closed Tb(3+) ions. The blue to cyan shift observed for the slightly doped materials, when excitation wavelength shifts from 378 nm to 262 nm, is due to different relaxation phenomena, from the (5)D3 level for a 378 nm excitation wavelength and from the (5)D4 level via the 4f5d level for a 262 nm excitation wavelength. Under a 378 nm wavelength, the co-doped La0.93Eu0.03Tb0.04H(O3PCH3)2 hybrid exhibits a white/cyan emission with CIE coordinates equal to x = 0.29, y = 0.37.
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Affiliation(s)
- B Mutelet
- Laboratoire CRISMAT, CNRS UMR6508, ENSICAEN, Université de Caen - Basse Normandie, 6 Bd Maréchal Juin, 14050 Caen Cedex, France.
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Rotella H, Copie O, Pautrat A, Boullay P, David A, Pelloquin D, Labbé C, Frilay C, Prellier W. Two components for one resistivity in LaVO3/SrTiO3 heterostructure. J Phys Condens Matter 2015; 27:095603. [PMID: 25688927 DOI: 10.1088/0953-8984/27/9/095603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A series of 100 nm LaVO3 thin films have been synthesized on (0 0 1)-oriented SrTiO3 substrates using the pulsed laser deposition technique, and the effects of growth temperature are analyzed. Transport properties reveal a large electronic mobility and a non-linear Hall effect at low temperature. In addition, a cross-over from a semiconducting state at high-temperature to a metallic state at low-temperature is observed, with a clear enhancement of the metallic character as the growth temperature increases. Optical absorption measurements combined with the two-bands analysis of the Hall effect show that the metallicity is induced by the diffusion of oxygen vacancies in the SrTiO3 substrate. These results allow us to understand that the film/substrate heterostructure behaves as an original semiconducting-metallic parallel resistor, and electronic transport properties are consistently explained.
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Affiliation(s)
- H Rotella
- Laboratoire CRISMAT, CNRS UMR 6508, ENSICAEN et Université de Caen, 6 Bd Maréchal Juin, 14050 Caen Cedex 4, France. NUSNNI-NanoCore, National University of Singapore, 117411 Singapore
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Moine LM, Labbé C, Louis-Seize G, Seifert KA, Bélanger RR. Identification and Detection of Fusarium striatum as a New Record of Pathogen to Greenhouse Tomato in Northeastern America. Plant Dis 2014; 98:292-298. [PMID: 30708442 DOI: 10.1094/pdis-08-13-0844-re] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Recently, a new disease was reported on greenhouse tomato plants in both Quebec, Canada and Maine, United States. Symptomatic plants bore brown lesions at graft points and pruning sites, resulting in expanding cankers with clearly delineated margins. Diseased plants eventually wilted and died within a few weeks following the appearance of the first symptoms. The symptoms are reminiscent of infection by Fusarium oxysporum f. sp. radicis-lycopersici, with the notable difference of a discoloration of the pith area rather than the vascular tissues. A homothallic Fusarium sp. was consistently recovered from these lesions. Sequencing of the internal transcribed spacer and the partial translation elongation factor 1-α gene identified the species as F. striatum. Pathogenicity tests with F. striatum isolates from diseased tissues reproduced disease symptoms in tomato similar to those observed on tomato plants in the greenhouses. Specific detection of F. striatum from mycelia and diseased and disease-free plant tissues was achieved by developing a polymerase chain reaction-based test. These results establish, for the first time, that the species F. striatum is the cause of crown and stem rot affecting tomato in North America. In addition F. striatum was detected from all sampled tissues of plants delivered by the nursery common to both growers, suggesting that the transplants would be the source of the inoculum.
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Affiliation(s)
- Lauriane M Moine
- Département de Phytologie, Faculté des Sciences de l'agriculture et de l'alimentation, Centre de Recherche en Horticulture, Université Laval, Pavillon Paul-Comtois, Quebec, QC, Canada, G1V 0A6
| | - Caroline Labbé
- Département de Phytologie, Faculté des Sciences de l'agriculture et de l'alimentation, Centre de Recherche en Horticulture, Université Laval, Pavillon Paul-Comtois, Quebec, QC, Canada, G1V 0A6
| | - Gerry Louis-Seize
- Département de Phytologie, Faculté des Sciences de l'agriculture et de l'alimentation, Centre de Recherche en Horticulture, Université Laval, Pavillon Paul-Comtois, Quebec, QC, Canada, G1V 0A6
| | - Keith A Seifert
- Biodiversity (Mycology and Microbiology), Agriculture and Agri-Food Canada, Ottawa, ON, Canada K1A 0C6
| | - Richard R Bélanger
- Département de Phytologie, Faculté des Sciences de l'agriculture et de l'alimentation, Centre de Recherche en Horticulture, Université Laval, Quebec
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Deshmukh RK, Vivancos J, Guérin V, Sonah H, Labbé C, Belzile F, Bélanger RR. Identification and functional characterization of silicon transporters in soybean using comparative genomics of major intrinsic proteins in Arabidopsis and rice. Plant Mol Biol 2013; 83:303-15. [PMID: 23771580 DOI: 10.1007/s11103-013-0087-3] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 06/03/2013] [Indexed: 05/18/2023]
Abstract
Silicon (Si) confers several benefits to many plant species when absorbed as silicic acid through nodulin 26-like intrinsic proteins (NIPs). The NIPs belong to major intrinsic protein (MIP) family, members of which form channels with high selectivity to control transport of water and different solutes. Here, comparative genomic analysis of the MIPs was performed to investigate the presence of Si transporter MIPs in soybean. Thorough analysis of phylogeny, gene organization, transcriptome profiling and protein modeling was performed to characterize MIPs in rice, Arabidopsis and soybean. Based on several attributes, two putative Si transporter genes, GmNIP2-1 and GmNIP2-2, were identified, characterized and cloned from soybean. Expression of both genes was detected in shoot and root tissues, and decreased as Si increased. The protein encoded by GmNIP2-2 showed functionality for Si transport when expressed in Xenopus oocytes, thus confirming the genetic capability of soybean to absorb the element. Comparative analysis of MIPs in plants provides opportunities to decipher gene evolution, functionality and selectivity of nutrient uptake mechanisms. Exploitation of this strategy has helped to uncover unique features of MIPs in soybean. The identification and functional characterization of Si transporters can be exploited to optimize the benefits that plants can derive from Si absorption.
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Affiliation(s)
- Rupesh K Deshmukh
- Département de Phytologie, Faculté des Sciences de l'Agriculture et de l'Alimentation, Centre de Recherche en Horticulture, Université Laval, Quebec, Canada
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Lefebvre F, Joly DL, Labbé C, Teichmann B, Linning R, Belzile F, Bakkeren G, Bélanger RR. The transition from a phytopathogenic smut ancestor to an anamorphic biocontrol agent deciphered by comparative whole-genome analysis. Plant Cell 2013; 25:1946-59. [PMID: 23800965 PMCID: PMC3723605 DOI: 10.1105/tpc.113.113969] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Pseudozyma flocculosa is related to the model plant pathogen Ustilago maydis yet is not a phytopathogen but rather a biocontrol agent of powdery mildews; this relationship makes it unique for the study of the evolution of plant pathogenicity factors. The P. flocculosa genome of ~23 Mb includes 6877 predicted protein coding genes. Genome features, including hallmarks of pathogenicity, are very similar in P. flocculosa and U. maydis, Sporisorium reilianum, and Ustilago hordei. Furthermore, P. flocculosa, a strict anamorph, revealed conserved and seemingly intact mating-type and meiosis loci typical of Ustilaginales. By contrast, we observed the loss of a specific subset of candidate secreted effector proteins reported to influence virulence in U. maydis as the singular divergence that could explain its nonpathogenic nature. These results suggest that P. flocculosa could have once been a virulent smut fungus that lost the specific effectors necessary for host compatibility. Interestingly, the biocontrol agent appears to have acquired genes encoding secreted proteins not found in the compared Ustilaginales, including necrosis-inducing-Phytophthora-protein- and Lysin-motif- containing proteins believed to have direct relevance to its lifestyle. The genome sequence should contribute to new insights into the subtle genetic differences that can lead to drastic changes in fungal pathogen lifestyles.
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Affiliation(s)
| | - David L. Joly
- Agriculture and Agri-Food Canada, Pacific Agri-Food Research Centre, Summerland V0H 1Z0, Canada
| | - Caroline Labbé
- Département de Phytologie, Université Laval, Quebec G1V 0A6, Canada
| | - Beate Teichmann
- Département de Phytologie, Université Laval, Quebec G1V 0A6, Canada
| | - Rob Linning
- Agriculture and Agri-Food Canada, Pacific Agri-Food Research Centre, Summerland V0H 1Z0, Canada
| | - François Belzile
- Département de Phytologie, Université Laval, Quebec G1V 0A6, Canada
| | - Guus Bakkeren
- Agriculture and Agri-Food Canada, Pacific Agri-Food Research Centre, Summerland V0H 1Z0, Canada
| | - Richard R. Bélanger
- Département de Phytologie, Université Laval, Quebec G1V 0A6, Canada
- Address correspondence to
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Mehonic A, Vrajitoarea A, Cueff S, Hudziak S, Howe H, Labbé C, Rizk R, Pepper M, Kenyon AJ. Quantum conductance in silicon oxide resistive memory devices. Sci Rep 2013; 3:2708. [PMID: 24048282 PMCID: PMC3776960 DOI: 10.1038/srep02708] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [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] [Received: 05/29/2013] [Accepted: 08/27/2013] [Indexed: 11/16/2022] Open
Abstract
Resistive switching offers a promising route to universal electronic memory, potentially replacing current technologies that are approaching their fundamental limits. In many cases switching originates from the reversible formation and dissolution of nanometre-scale conductive filaments, which constrain the motion of electrons, leading to the quantisation of device conductance into multiples of the fundamental unit of conductance, G0. Such quantum effects appear when the constriction diameter approaches the Fermi wavelength of the electron in the medium - typically several nanometres. Here we find that the conductance of silicon-rich silica (SiOx) resistive switches is quantised in half-integer multiples of G0. In contrast to other resistive switching systems this quantisation is intrinsic to SiOx, and is not due to drift of metallic ions. Half-integer quantisation is explained in terms of the filament structure and formation mechanism, which allows us to distinguish between systems that exhibit integer and half-integer quantisation.
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Affiliation(s)
- A. Mehonic
- Department of Electronic & Electrical Engineering, UCL, Torrington Place, London WC1E 7JE, UK
| | - A. Vrajitoarea
- Department of Electronic & Electrical Engineering, UCL, Torrington Place, London WC1E 7JE, UK
| | - S. Cueff
- Centre de Recherche sur les Ions, les Matériaux et la Photonique (CIMAP), UMR 6252 CNRS/CEA/Ensicaen/UCBN, 6 Boulevard Maréchal Juin, 14050 Caen Cedex 4, France
- Brown University, School of Engineering, Providence, Rhode Island 02912, USA
| | - S. Hudziak
- Department of Electronic & Electrical Engineering, UCL, Torrington Place, London WC1E 7JE, UK
| | - H. Howe
- Department of Electronic & Electrical Engineering, UCL, Torrington Place, London WC1E 7JE, UK
| | - C. Labbé
- Centre de Recherche sur les Ions, les Matériaux et la Photonique (CIMAP), UMR 6252 CNRS/CEA/Ensicaen/UCBN, 6 Boulevard Maréchal Juin, 14050 Caen Cedex 4, France
| | - R. Rizk
- Centre de Recherche sur les Ions, les Matériaux et la Photonique (CIMAP), UMR 6252 CNRS/CEA/Ensicaen/UCBN, 6 Boulevard Maréchal Juin, 14050 Caen Cedex 4, France
| | - M. Pepper
- Department of Electronic & Electrical Engineering, UCL, Torrington Place, London WC1E 7JE, UK
| | - A. J. Kenyon
- Department of Electronic & Electrical Engineering, UCL, Torrington Place, London WC1E 7JE, UK
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Grégoire C, Rémus-Borel W, Vivancos J, Labbé C, Belzile F, Bélanger RR. Discovery of a multigene family of aquaporin silicon transporters in the primitive plant Equisetum arvense. Plant J 2012; 72:320-30. [PMID: 22712876 DOI: 10.1111/j.1365-313x.2012.05082.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Plants benefit greatly from silicon (Si) absorption provided that they contain Si transporters. The latter have recently been identified in the roots of some higher plants known to accumulate high concentrations of Si, and all share a high level of sequence identity. In this study, we searched for transporters in the primitive vascular plant Equisetum arvense (horsetail), which is a valuable but neglected model plant for the study of Si absorption, as it has one of the highest Si concentrations in the plant kingdom. Our initial attempts to identify Si transporters based on sequence homology with transporters from higher plants proved unsuccessful, suggesting a divergent structure or property in horsetail transporters. Subsequently, through sequencing of the horsetail root transcriptome and a search using amino acid sequences conserved in plant aquaporins, we were able to identify a multigene family of aquaporin Si transporters. Comparison of known functional domains and phylogenetic analysis of sequences revealed that the horsetail proteins belong to a different group than higher-plant Si transporters. In particular, the newly identified proteins contain a STAR pore as opposed to the GSGR pore common to all previously identified Si transporters. In order to determine its functionality, the proteins were heterologously expressed in both Xenopus oocytes and Arabidopsis, and the results showed that the horsetail proteins are extremely efficient a transporting Si. These findings offer new insights into the elusive properties of Si and its absorption by plants.
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Affiliation(s)
- Caroline Grégoire
- Département de Phytologie-Faculté des Sciences de l'Agriculture et de l'Alimentation, Centre de Recherche en Horticulture, Université Laval, Pavillon Paul-Comtois, Québec City, QC G1V 0A6, Canada
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Pillet E, Barenton M, Méa F, Labbé C, Duchamp G, Desherces S, Schmitt E, Magistrini M. Which alternatives to milk and egg yolk in stallion freezing extenders? J Equine Vet Sci 2012. [DOI: 10.1016/j.jevs.2012.06.081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Teichmann B, Labbé C, Lefebvre F, Bölker M, Linne U, Bélanger RR. Identification of a biosynthesis gene cluster for flocculosin a cellobiose lipid produced by the biocontrol agent Pseudozyma flocculosa. Mol Microbiol 2011; 79:1483-95. [DOI: 10.1111/j.1365-2958.2010.07533.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Mauger PE, Labbé C, Bobe J, Cauty C, Leguen I, Baffet G, Le Bail PY. Characterization of goldfish fin cells in culture: some evidence of an epithelial cell profile. Comp Biochem Physiol B Biochem Mol Biol 2008; 152:205-15. [PMID: 19068235 DOI: 10.1016/j.cbpb.2008.11.003] [Citation(s) in RCA: 19] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Revised: 11/06/2008] [Accepted: 11/12/2008] [Indexed: 12/20/2022]
Abstract
Comprehensive characterization of cultured cells in fish was little explored and cell origin is often deduced from morphological analogies with either epithelial of fibroblastic cells. This study aims to characterize cell origin in goldfish fin culture using morphological, immunochemical, and molecular approaches. Time lapse analysis revealed that cultured cell morphology changed within minutes. Therefore, cell morphology cannot predict whether cells are from fibroblastic or epithelial origin. The labeling pattern of heterologous anti-cytokeratin and anti-vimentin antibodies against goldfish epithelial cells and fibroblasts was first tested on skin sections and the corresponding labeling of the cultured cells was analyzed. No cell origin specificity could be obtained with the chosen antibodies. In the molecular approach, detection levels of three cytokeratin (CauK8-IIS, CauK49-IE and CauK50-Ie) and one vimentin transcripts were assessed on skin and fin samples. Specificity for epithelial cells of the most abundant mRNA, CauK49-Ie, was thereafter validated on skin sections by in situ hybridization. The selected markers were used afterwards to characterize fin cultures. CauK49-IE riboprobe labeled every cell in young cultures whereas no labeling was observed in older cultures. Accordingly, CauK49-IE transcript levels decreased after 15 days culture while CauK8-IIS ones increased. The use of homologous marker gave evidence that young cultured cells from goldfish fin are homogeneously of epithelial type and that cell characteristics may change over culture time.
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Affiliation(s)
- P-E Mauger
- Institut National de la Recherche Agronomique, UR 1037 SCRIBE, Campus de Beaulieu, Rennes cedex, France
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Labbé C, Goyette P, Lefebvre C, Stevens C, Green T, Tello-Ruiz MK, Cao Z, Landry AL, Stempak J, Annese V, Latiano A, Brant SR, Duerr RH, Taylor KD, Cho JH, Steinhart AH, Daly MJ, Silverberg MS, Xavier RJ, Rioux JD. MAST3: a novel IBD risk factor that modulates TLR4 signaling. Genes Immun 2008; 9:602-12. [PMID: 18650832 DOI: 10.1038/gene.2008.57] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Inflammatory bowel disease (IBD) is a chronic disorder caused by multiple factors in a genetically susceptible host. Significant advances in the study of genetic susceptibility have highlighted the importance of the innate immune system in this disease. We previously completed a genome-wide linkage study and found a significant locus (IBD6) on chromosome 19p. We were interested in identifying the causal variant in IBD6. We performed a two-stage association mapping study. In stage 1, 1530 single-nucleotide polymorphisms (SNPs) were selected from the HapMap database and genotyped in 761 patients with IBD. Among the SNPs that passed the threshold for replication, 26 were successfully genotyped in 754 additional patients (stage 2). One intronic variant, rs273506, located in the microtubule-associated serine/threonine-protein kinase gene-3 (MAST3), was found to be associated in both stages (pooled P=1.8 x 10(-4)). We identified four MAST3 coding variants, including a non-synonymous SNP rs8108738, correlated to rs273506 and associated with IBD. To test whether MAST3 was expressed in cells of interest, we performed expression assays, which showed abundant expression of MAST3 in antigen-presenting cells and in lymphocytes. The knockdown of MAST3 specifically decreased Toll-like receptor-4-dependent NF-kappaB activity. Our findings are additional proofs of the pivotal role played by modulators of NF-kappaB activity in IBD pathogenesis.
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Affiliation(s)
- C Labbé
- Institut de Cardiologie de Montréal, Montréal, Québec, Canada
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Neveu B, Labbé C, Bélanger RR. GFP technology for the study of biocontrol agents in tritrophic interactions: A case study with Pseudozyma flocculosa. J Microbiol Methods 2007; 68:275-81. [PMID: 17028024 DOI: 10.1016/j.mimet.2006.08.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2006] [Revised: 08/08/2006] [Accepted: 08/19/2006] [Indexed: 10/24/2022]
Abstract
GFP technology was applied to the biocontrol agent (BCA) Pseudozyma flocculosa to study its development and interactions at the tritrophic level plant-powdery mildew-BCA. Transformation experiments with GFP led to the production of a strongly fluorescent strain, Act-4, that displayed biocontrol traits typical of P. flocculosa WT. Following inundative applications, growth of P. flocculosa Act-4 was closely and almost exclusively associated with the colonies of the pathogen regardless of the powdery mildew species or the host plant tested. Development of P. flocculosa Act-4 on control leaves alone was extremely limited 24 h after its application and was typical of the epiphytic growth characterizing this type of yeast-like fungus. Based on the strong correlation between the colonization pattern of the different powdery mildew species tested and the presence of P. flocculosa Act-4, as determined by its fluorescence, it seems that growth of the BCA is dependant on the presence of powdery mildews. These results demonstrate that the GFP technology can be used to study plant-pathogen-BCA interactions and fulfill a wide array of purposes ranging from fundamental observations of the biocontrol behavior of a BCA to very applied ones serving some of the requirements for the registration of BCA's such as defining their environmental fate.
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Affiliation(s)
- Bertrand Neveu
- Département de Phytologie, Centre de Recherche en Horticulture, Pavillon Envirotron, Université Laval, Québec, Canada G1K 7P4
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Rémus-Borel W, Shallow N, McNally DJ, Labbé C, Bélanger RR. High-speed counter-current chromatography for the study of defense metabolites in wheat. J Chromatogr A 2006; 1121:200-8. [PMID: 16650851 DOI: 10.1016/j.chroma.2006.04.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2006] [Revised: 03/30/2006] [Accepted: 04/07/2006] [Indexed: 10/24/2022]
Abstract
High-speed counter-current chromatography (HSCCC) methods were developed for the study of induced defense metabolites in wheat (Triticum aestivum) against powdery mildew (Blumeria graminis f. sp. tritici). A single HSCCC purification step afforded extraction of mg-quantities of an induced compound with antifungal activity. Subsequent LC-MS and NMR analyses have led to the characterization of 5,6-O-methyl trans-aconitic acid, the first such report of this compound in a plant species. The inducible nature of aconitic acid was evidenced by comparing the metabolite profiles of leaf extracts from plants treated or not with soluble silicon and infected or not with powdery mildew. In a second step, dual-mode HSCCC was used to enhance the separation of other forms of aconitic acid in wheat. Based on these results, it was concluded that 5,6-O-methyl trans-aconitic acid plays an important role as a defense molecule in wheat plants and that HSCCC is a powerful separation method for purifying such compounds from complex plant-pathogen interactions.
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Mauger PE, Le Bail PY, Labbé C. Cryobanking of fish somatic cells: Optimizations of fin explant culture and fin cell cryopreservation. Comp Biochem Physiol B Biochem Mol Biol 2006; 144:29-37. [PMID: 16503180 DOI: 10.1016/j.cbpb.2006.01.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2005] [Revised: 01/11/2006] [Accepted: 01/11/2006] [Indexed: 10/25/2022]
Abstract
When gametes or embryos are not available, somatic cells should be considered for fish genome cryobanking of valuable or endangered fish. The objective of this work was to develop a method for fin explant culture with an assessed reliability, and to assess fin cells ability to cryopreservation. Anal fins from goldfish (Carassius auratus) were minced and gently loosened with collagenase before explants were plated at 20 degrees C in L-15 medium supplemented with fetal bovine serum and pH buffering additives. Quantification of cell-donor explants per fin rated the culture success. Cells were successfully obtained from every cultured anal fin (mean = 65% cell-donor explant per fin). All other fin types were suitable except the dorsal fin. Explant plating could be deferred 3 days from fin collecting. Fins from seven other fish species were successfully cultured with the method. After 2-3 weeks, sub-confluent fin cells from goldfish were cryopreserved. Cryopreservation with dimethyl sulfoxide and sucrose at a slow freezing rate allowed the recovery of half the goldfish fin cells. Cells displayed the same viability as fresh ones. 1,2-propanediol was unsuitable when a fast freezing rate was used. The procedure could now be considered for cryobanking with only minimal adaptation to each new species.
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Affiliation(s)
- P-E Mauger
- Group for cell cryopreservation and fish reconstruction, IFR 140, INRA-SCRIBE, Campus de Beaulieu, 35042 Rennes Cedex, France
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Avis TJ, Cheng YL, Zhao YY, Bolduc S, Neveu B, Anguenot R, Labbé C, Belzile F, Bélanger RR. The potential of Pseudozyma yeastlike epiphytes for the production of heterologous recombinant proteins. Appl Microbiol Biotechnol 2005; 69:304-11. [PMID: 15830195 DOI: 10.1007/s00253-005-1986-2] [Citation(s) in RCA: 16] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2005] [Revised: 03/24/2005] [Accepted: 03/31/2005] [Indexed: 11/27/2022]
Abstract
Although Basidiomycetes represent the most evolved class of fungi, they have been neglected with regard to recombinant gene expression. In this work, basidiomycetous yeasts belonging to Pseudozyma spp. were studied with respect to their amenability to heterologous protein production. Single plasmid or cotransformation experiments routinely afforded 100 to 200 independent transformants for the two tested species of Pseudozyma. Green fluorescent protein (GFP) was expressed in the correctly folded conformation, as demonstrated by fluorescence microscopy, and hen egg white lysozyme (HEWL) was expressed in its active form, as revealed by its lytic activity on Micrococcus lysodeikticus cells. Protease analysis established that Pseudozyma spp. contained equivalent or less extracellular protease activity than yeasts and far less protease activity than ascomycetous filamentous fungi in similar culture conditions. This proteolytic activity was inhibited by over 97% with a combination of PMSF and Pepstatin A. N-glycosylation patterns of native Pseudozyma flocculosa secreted proteins were comprised of one or a few short glycan chains that possess a classic eukaryotic structure typical of higher fungi and animal cells. This is the first report of a Basidiomycete that possesses multiple intrinsic characteristics necessary for use as a heterologous gene expression system.
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Affiliation(s)
- T J Avis
- Département de Phytologie, Centre de recherche en horticulture, Université Laval, Pavillon de l'Envirotron, Laval, Québec G1K 7P4, Canada
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Abstract
Flocculosin, a glycolipid isolated from the yeast-like fungus Pseudozyma flocculosa, was investigated for in vitro antifungal activity. The compound displayed antifungal properties against several pathogenic yeasts. Synergistic activity was observed between flocculosin and amphotericin B, and no significant cytotoxicity was demonstrated when tested against human cell lines.
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Affiliation(s)
- Benjamin Mimee
- Centre de Recherche en Horticulture, Université Laval, Québec, Canada G1K 7P4
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Fofana B, Benhamou N, McNally DJ, Labbé C, Séguin A, Bélanger RR. Suppression of induced resistance in cucumber through disruption of the flavonoid pathway. Phytopathology 2005; 95:114-23. [PMID: 18943844 DOI: 10.1094/phyto-95-0114] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
ABSTRACT In this study, cucumber plants (Cucumis sativus) expressing induced resistance against powdery mildew (caused by Podosphaera xanthii) were infiltrated with inhibitors of cinnamate 4-hydroxylase, 4-coumarate:CoA ligase (4CL), and chalcone synthase (CHS) to evaluate the role of flavonoid phytoalexin production in induced disease resistance. Light and transmission electron microscopy demonstrated ultrastructural changes in inhibited plants, and biochemical analyses determined levels of CHS and beta-glucosidase enzyme activity and 4CL protein accumulation. Our results showed that elicited plants displayed a high level of induced resistance. In contrast, down regulation of CHS, a key enzyme of the flavonoid pathway, resulted in nearly complete suppression of induced resistance, and microscopy confirmed the development of healthy fungal haustoria within these plants. Inhibition of 4CL ligase, an enzyme largely responsible for channeling phenylpropanoid metabolites into the lignin pathway, had little effect on induced disease resistance. Biochemical analyses revealed similar levels of 4CL protein accumulation for all treatments, suggesting no alterations of nontargeted functions within inhibited plants. Collectively, the results of this study support the idea that induced resistance in cucumber is largely correlated with rapid de novo biosynthesis of flavonoid phytoalexin compounds.
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Douard V, Hermier D, Magistrini M, Labbé C, Blesbois E. Impact of changes in composition of storage medium on lipid content and quality of turkey spermatozoa. Theriogenology 2004; 61:1-13. [PMID: 14643857 DOI: 10.1016/s0093-691x(03)00180-8] [Citation(s) in RCA: 16] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Turkey semen quality is damaged by long term in vitro storage. The objective of the present study was to determine whether changes in energy substrates and antioxidants of semen extender could limit loss of quality and lipid content of turkey spermatozoa during storage. Spermatozoa were incubated in extenders based on Beltsville Poultry Semen Extender (BPSE) to which different energy substrates (acetate, pyruvate and hydroxybutyric acid) or antioxidant (Vitamin E) had been added. Semen was stored at 4 degrees C for 48 h and changes in quality, phospholipid and malondialdehyde (MDA) content of semen were evaluated. Among the different substrates studied, only acetate was able to limit the loss of motility and ATP content after 48 h in vitro storage. Losses of spermatozoal phospholipids were similar when gametes were incubated in an extender without any substrate or in normal BPSE (784-675nmol/10(9) spz versus 837-703 nmol/10(9) spz). However, motility and ATP content were significantly more affected after 48 h of storage in samples incubated without substrates than in BPSE (motility, 2.2 versus 0; ATP, 10 nmol/10(9) spz versus 3 nmol/10(9) spz). The addition of Vitamin E to the extender did not modify either the MDA or phospholipid content of fresh or stored spermatozoa, but increased the motility of stored semen. In conclusion, acetate is an essential substrate for in vitro storage. Spermatozoal phospholipids decreased during storage, but this did not seem to originate from metabolism of endogenous fatty acids. The positive effects of Vitamin E on semen storage did not originate from preservation of lipid oxidation.
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Affiliation(s)
- V Douard
- Station de Recherches Avicoles, INRA, F-37380, Nouzilly, France
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Rodrigues FA, McNally DJ, Datnoff LE, Jones JB, Labbé C, Benhamou N, Menzies JG, Bélanger RR. Silicon enhances the accumulation of diterpenoid phytoalexins in rice: a potential mechanism for blast resistance. Phytopathology 2004; 94:177-83. [PMID: 18943541 DOI: 10.1094/phyto.2004.94.2.177] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
ABSTRACT Although several reports underscore the importance of silicon (Si) in controlling Magnaporthe grisea on rice, no study has associated this beneficial effect with specific mechanisms of host defense responses against this fungal attack. In this study, however, we provide evidence that higher levels of momilactone phytoalexins were found in leaf extracts from plants inoculated with M. grisea and amended with silicon (Si(+)) than in leaf extracts from inoculated plants not amended with silicon (Si(-) ) or noninoculated Si(+) and Si(-) plants. On this basis, the more efficient stimulation of the terpenoid pathway in Si(+) plants and, consequently, the increase in the levels of momilactones appears to be a factor contributing to enhanced rice resistance to blast. This may explain the lower level of blast severity observed on leaves of Si(+) plants at 96 h after inoculation with M. grisea. The results of this study strongly suggest that Si plays an active role in the resistance of rice to blast rather than the formation of a physical barrier to penetration by M. grisea.
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Abstract
Extraction of cucumber leaf tissue expressing induced resistance against powdery mildew fungi revealed the presence of two new major C-glycosyl flavonoid products: vitexin-6-(4-hydroxy-1-ethylbenzene) (cucumerin A, 1) and isovitexin-8-(4-hydroxy-1-ethylbenzene) (cucumerin B, 2). In addition, the known C-glycosyl flavonoids apigenin-8-C-beta-D-glucopyranoside (vitexin, 3), apigenin-6-C-beta-D-glucopyranoside (isovitexin, 4), luteolin-8-C-beta-D-glucopyranoside (orientin, 5), and luteolin-6-C-beta-D-glucopyranoside (isoorientin, 6), as well as 4-hydroxycinnamic acid (p-coumaric acid, 7) and its methyl ester (p-came, 8), were found in higher quantities within resistant plants. The structures of 1-8 were elucidated using spectroscopic methods and unambiguously confirmed for 3-8 using co-chromatography experiments with authentic standards. On the basis of the results of this study and the reported biological activities of C-glycosyl flavonoids, these compounds would play a vital role in the defense strategy of this species by acting as phytoalexins.
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Affiliation(s)
- David J McNally
- Département de Phytologie, Centre de Recherche en Horticulture, Université Laval, Sainte-Foy, QC, G1K 7P4, Canada
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