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Qayyum Z, Thomas WJW, Amas JC, Pazos-Navarro M, Batley J. From Recognition to Response: Resistance-Effector Gene Interactions in the Brassica napus and Leptosphaeria maculans Patho-System. PLANTS (BASEL, SWITZERLAND) 2025; 14:390. [PMID: 39942952 PMCID: PMC11821207 DOI: 10.3390/plants14030390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2024] [Revised: 01/14/2025] [Accepted: 01/22/2025] [Indexed: 02/16/2025]
Abstract
Blackleg disease, caused by the hemibiotrophic fungal pathogen Leptosphaeria maculans, poses a serious threat to Brassica crops and requires a broad understanding of the plant defence mechanisms. The Brassica. napus-L. maculans pathosystem provides a useful model to understand plant resistance response to hemibiotrophs. This review aims to explain the mechanisms underlying R-Avr interaction, signalling cascades, and the hypersensitive response (HR) produced by B. napus towards L. maculans, causing local cell death that restricts the pathogen to the site of infection. The role of transcription factors is pivotal to the process of HR, coordinating the regulation of genes involved in pathogen recognition and the activation of SA responsive genes and production of secondary metabolites. The R-Avr interaction signalling cascade involves production of reactive oxygen species (ROS), calcium ion influx, Salicylic acid (SA) hormonal signalling and mitogen activated protein kinases (MAPKs), which are critical in the HR in B. napus. The in-depth understanding of molecular signalling pathway of the R-Avr interaction between B. napus-L. maculans pathosystem provides valuable information for future research endeavours regarding enhancing disease resistance in Brassica crops.
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Affiliation(s)
| | | | | | | | - Jacqueline Batley
- School of Biological Sciences, University of Western Australia, Perth, WA 6009, Australia; (Z.Q.); (W.J.W.T.); (J.C.A.); (M.P.-N.)
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2
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Li J, Wyatt NA, Skiba RM, Kariyawasam GK, Richards JK, Effertz K, Rehman S, Liu Z, Brueggeman RS, Friesen TL. Variability in Chromosome 1 of Select Moroccan Pyrenophora teres f. teres Isolates Overcomes a Highly Effective Barley Chromosome 6H Source of Resistance. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2024; 37:676-687. [PMID: 38888557 DOI: 10.1094/mpmi-10-23-0159-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
Barley net form net blotch (NFNB) is a destructive foliar disease caused by Pyrenophora teres f. teres. Barley line CIho5791, which harbors the broadly effective chromosome 6H resistance gene Rpt5, displays dominant resistance to P. teres f. teres. To genetically characterize P. teres f. teres avirulence/virulence on the barley line CIho5791, we generated a P. teres f. teres mapping population using a cross between the Moroccan CIho5791-virulent isolate MorSM40-3 and the avirulent reference isolate 0-1. Full genome sequences were generated for 103 progenies. Saturated chromosome-level genetic maps were generated, and quantitative trait locus (QTL) mapping identified two major QTL associated with P. teres f. teres avirulence/virulence on CIho5791. The most significant QTL mapped to chromosome (Ch) 1, where the virulent allele was contributed by MorSM40-3. A second QTL mapped to Ch8; however, this virulent allele was contributed by the avirulent parent 0-1. The Ch1 and Ch8 loci accounted for 27 and 15% of the disease variation, respectively, and the avirulent allele at the Ch1 locus was epistatic over the virulent allele at the Ch8 locus. As a validation, we used a natural P. teres f. teres population in a genome-wide association study that identified the same Ch1 and Ch8 loci. We then generated a new reference quality genome assembly of parental isolate MorSM40-3 with annotation supported by deep transcriptome sequencing of infection time points. The annotation identified candidate genes predicted to encode small, secreted proteins, one or more of which are likely responsible for overcoming the CIho5791 resistance. [Formula: see text] The author(s) have dedicated the work to the public domain under the Creative Commons CC0 "No Rights Reserved" license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2024.
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Affiliation(s)
- Jinling Li
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58102, U.S.A
| | - Nathan A Wyatt
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58102, U.S.A
- Sugarbeet and Potato Research Unit, Edward T. Schafer Agricultural Research Center, USDA-ARS, Fargo, ND 58102, U.S.A
| | - Ryan M Skiba
- Cereal Crops Research Unit, Edward T. Schafer Agricultural Research Center, USDA-ARS, Fargo, ND 58102, U.S.A
| | - Gayan K Kariyawasam
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58102, U.S.A
| | - Jonathan K Richards
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, U.S.A
| | - Karl Effertz
- Department of Crop and Soil Science, Washington State University, Pullman, WA 99164, U.S.A
| | - Sajid Rehman
- Biodiversity and Crop Improvement Program, International Center for Agricultural Research in the Dry Areas (ICARDA), Rabat 10100, Morocco
- Field Crop Development Center of the Olds College, Lacombe, Alberta T4L1W8, Canada
| | - Zhaohui Liu
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58102, U.S.A
| | - Robert S Brueggeman
- Department of Crop and Soil Science, Washington State University, Pullman, WA 99164, U.S.A
| | - Timothy L Friesen
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58102, U.S.A
- Cereal Crops Research Unit, Edward T. Schafer Agricultural Research Center, USDA-ARS, Fargo, ND 58102, U.S.A
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Vasquez-Teuber P, Rouxel T, Mason AS, Soyer JL. Breeding and management of major resistance genes to stem canker/blackleg in Brassica crops. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2024; 137:192. [PMID: 39052130 PMCID: PMC11272824 DOI: 10.1007/s00122-024-04641-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 04/29/2024] [Indexed: 07/27/2024]
Abstract
Blackleg (also known as Phoma or stem canker) is a major, worldwide disease of Brassica crop species, notably B. napus (rapeseed, canola), caused by the ascomycete fungus Leptosphaeria maculans. The outbreak and severity of this disease depend on environmental conditions and management practices, as well as a complex interaction between the pathogen and its hosts. Genetic resistance is a major method to control the disease (and the only control method in some parts of the world, such as continental Europe), but efficient use of genetic resistance is faced with many difficulties: (i) the scarcity of germplasm/genetic resources available, (ii) the different history of use of resistance genes in different parts of the world and the different populations of the fungus the resistance genes are exposed to, (iii) the complexity of the interactions between the plant and the pathogen that expand beyond typical gene-for-gene interactions, (iv) the incredible evolutionary potential of the pathogen and the importance of knowing the molecular processes set up by the fungus to "breakdown' resistances, so that we may design high-throughput diagnostic tools for population surveys, and (v) the different strategies and options to build up the best resistances and to manage them so that they are durable. In this paper, we aim to provide a comprehensive overview of these different points, stressing the differences between the different continents and the current prospects to generate new and durable resistances to blackleg disease.
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Affiliation(s)
- Paula Vasquez-Teuber
- Department of Plant Breeding, Justus Liebig University, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany
- Department of Plant Production, Faculty of Agronomy, University of Concepción, Av. Vicente Méndez 595, Chillán, Chile
- Plant Breeding Department, University of Bonn, Katzenburgweg 5, 53115, Bonn, Germany
| | - Thierry Rouxel
- Université Paris-Saclay, INRAE, UR BIOGER, 91120, Palaiseau, France
| | - Annaliese S Mason
- Department of Plant Breeding, Justus Liebig University, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.
- Plant Breeding Department, University of Bonn, Katzenburgweg 5, 53115, Bonn, Germany.
| | - Jessica L Soyer
- Université Paris-Saclay, INRAE, UR BIOGER, 91120, Palaiseau, France.
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Balesdent MH, Laval V, Noah JM, Bagot P, Mousseau A, Rouxel T. Large-scale population survey of Leptosphaeria maculans in France highlights both on-going breakdowns and potentially effective resistance genes in oilseed rape. PEST MANAGEMENT SCIENCE 2024; 80:2426-2434. [PMID: 36750403 DOI: 10.1002/ps.7401] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 01/03/2023] [Accepted: 02/08/2023] [Indexed: 06/18/2023]
Abstract
BACKGROUND Leptosphaeria maculans, the cause of stem canker of oilseed rape, develops gene-for-gene interactions with its host and shows a high evolutionary potential to 'break down' novel resistance genes (R, Rlm) deployed in cultivars over large areas. For optimal management of R genes, updated knowledge of the population structure of the pathogen is needed. In France, large-scale surveys have been done at 10-year intervals since 2000. Here we report the characterization of a large L. maculans population collected in France in 2019-2020. RESULTS A total of 844 isolates were collected from 11 sites in ten French departments and were phenotyped for their virulence against nine Brassica napus R genes. All isolates were virulent toward Rlm2 and Rlm9. Very few isolates were avirulent on Rlm1 (1.8%) and Rlm4 (0.6%). Avirulent isolates toward Rlm7 ('AvrLm7') varied from 67% to 11.3%, depending on the site sampled, illustrating the ongoing breakdown of Rlm7. The decrease of AvrLm7 isolates (29.2% at the national level) compared to the 2010 survey (96.5%) was accompanied by an increase of avirulent isolates on Rlm3 (0% in 2010; 54% in 2019-2020). However, virulent isolates on both Rlm3 and Rlm7, previously rarely detected, were found in all sites with a frequency of 17.3%. Finally, most or all isolates were avirulent on Rlm11 (96.1%), LepR2 (RlmS, 99.8%), and Rlm6 (100%), suggesting these three genes still effectively control the disease. CONCLUSION These data will help guide strategies for breeding and deploying resistant oilseed rape varieties against L. maculans in France. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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Affiliation(s)
- Marie-Hélène Balesdent
- Université Paris-Saclay, INRAE, UR Bioger, 22, Place de l'Agronomie, Palaiseau, 91120, France
| | - Valérie Laval
- Université Paris-Saclay, INRAE, UR Bioger, 22, Place de l'Agronomie, Palaiseau, 91120, France
| | - Julie Marie Noah
- Université Paris-Saclay, INRAE, UR Bioger, 22, Place de l'Agronomie, Palaiseau, 91120, France
| | - Patrick Bagot
- GEVES, Domaine de l'Anjouère, La Pouëze, 49370, Erdre en Anjou, France
| | - Arnaud Mousseau
- GEVES, Domaine de l'Anjouère, La Pouëze, 49370, Erdre en Anjou, France
| | - Thierry Rouxel
- Université Paris-Saclay, INRAE, UR Bioger, 22, Place de l'Agronomie, Palaiseau, 91120, France
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5
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Clairet C, Gay EJ, Porquier A, Blaise F, Marais CL, Balesdent MH, Rouxel T, Soyer JL, Fudal I. Regulation of effector gene expression as concerted waves in Leptosphaeria maculans: a two-player game. THE NEW PHYTOLOGIST 2024; 242:247-261. [PMID: 38358035 DOI: 10.1111/nph.19581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 01/09/2024] [Indexed: 02/16/2024]
Abstract
Effector genes, encoding molecules involved in disease establishment, are concertedly expressed throughout the lifecycle of plant-pathogenic fungi. However, little is known about how effector gene expression is regulated. Since many effector genes are located in repeat-rich regions, the role of chromatin remodeling in their regulation was recently investigated, notably establishing that the repressive histone modification H3K9me3, deposited by KMT1, was involved in several fungal species including Leptosphaeria maculans. Nevertheless, previous data suggest that a second regulatory layer, probably involving a specific transcription factor (TF), might be required. In L. maculans, a Dothideomycete causing stem canker of oilseed rape, we identified the ortholog of Pf2, a TF belonging to the Zn2Cys6 fungal-specific family, and described as essential for pathogenicity and effector gene expression. We investigated its role together with KMT1, by inactivating and over-expressing LmPf2 in a wild-type strain and a ∆kmt1 mutant. Functional analyses of the corresponding transformants highlighted an essential role of LmPf2 in the establishment of pathogenesis and we found a major effect of LmPf2 on the induction of effector gene expression once KMT1 repression is lifted. Our results show, for the first time, a dual control of effector gene expression.
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Affiliation(s)
- Colin Clairet
- Université Paris-Saclay, INRAE, UR BIOGER, 91120, Palaiseau, France
| | - Elise J Gay
- Université Paris-Saclay, INRAE, UR BIOGER, 91120, Palaiseau, France
| | - Antoine Porquier
- Université Paris-Saclay, INRAE, UR BIOGER, 91120, Palaiseau, France
| | - Françoise Blaise
- Université Paris-Saclay, INRAE, UR BIOGER, 91120, Palaiseau, France
| | | | | | - Thierry Rouxel
- Université Paris-Saclay, INRAE, UR BIOGER, 91120, Palaiseau, France
| | - Jessica L Soyer
- Université Paris-Saclay, INRAE, UR BIOGER, 91120, Palaiseau, France
| | - Isabelle Fudal
- Université Paris-Saclay, INRAE, UR BIOGER, 91120, Palaiseau, France
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Talbi N, Blekemolen MC, Janevska S, Zendler D, van Tilbeurgh H, Fudal I, Takken FLW. Facilitation of Symplastic Effector Protein Mobility by Paired Effectors Is Conserved in Different Classes of Fungal Pathogens. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2024; 37:304-314. [PMID: 37782126 DOI: 10.1094/mpmi-07-23-0103-fi] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
It has been discovered that plant pathogens produce effectors that spread via plasmodesmata (PD) to allow modulation of host processes in distal uninfected cells. Fusarium oxysporum f. sp. lycopersici (Fol) facilitates effector translocation by expansion of the size-exclusion limit of PD using the Six5/Avr2 effector pair. How other fungal pathogens manipulate PD is unknown. We recently reported that many fungal pathogens belonging to different families carry effector pairs that resemble the SIX5/AVR2 gene pair from Fol. Here, we performed structural predictions of three of these effector pairs from Leptosphaeria maculans (Lm) and tested their ability to manipulate PD and to complement the virulence defect of a Fol SIX5 knockout mutant. We show that the AvrLm10A homologs are structurally related to FolSix5 and localize at PD when they are expressed with their paired effectors. Furthermore, these effectors were found to complement FolSix5 function in cell-to-cell mobility assays and in fungal virulence. We conclude that distantly related fungal species rely on structurally related paired effector proteins to manipulate PD and facilitate effector mobility. The wide distribution of these effector pairs implies Six5-mediated effector translocation to be a conserved propensity among fungal plant pathogens. [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)
- Nacera Talbi
- Université Paris-Saclay, INRAE, UR BIOGER, 91120 Palaiseau, France
| | - Mila C Blekemolen
- Molecular Plant Pathology, Swammerdam Institute of Life Science (SILS), University of Amsterdam, Amsterdam, the Netherlands
| | - Slavica Janevska
- Molecular Plant Pathology, Swammerdam Institute of Life Science (SILS), University of Amsterdam, Amsterdam, the Netherlands
| | - Daniel Zendler
- Molecular Plant Pathology, Swammerdam Institute of Life Science (SILS), University of Amsterdam, Amsterdam, the Netherlands
| | - Herman van Tilbeurgh
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Isabelle Fudal
- Université Paris-Saclay, INRAE, UR BIOGER, 91120 Palaiseau, France
| | - Frank L W Takken
- Molecular Plant Pathology, Swammerdam Institute of Life Science (SILS), University of Amsterdam, Amsterdam, the Netherlands
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7
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Talbi N, Fokkens L, Audran C, Petit‐Houdenot Y, Pouzet C, Blaise F, Gay EJ, Rouxel T, Balesdent M, Rep M, Fudal I. The neighbouring genes AvrLm10A and AvrLm10B are part of a large multigene family of cooperating effector genes conserved in Dothideomycetes and Sordariomycetes. MOLECULAR PLANT PATHOLOGY 2023; 24:914-931. [PMID: 37128172 PMCID: PMC10346447 DOI: 10.1111/mpp.13338] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 03/22/2023] [Accepted: 03/26/2023] [Indexed: 05/03/2023]
Abstract
Fungal effectors (small-secreted proteins) have long been considered as species or even subpopulation-specific. The increasing availability of high-quality fungal genomes and annotations has allowed the identification of trans-species or trans-genera families of effectors. Two avirulence effectors, AvrLm10A and AvrLm10B, of Leptosphaeria maculans, the fungus causing stem canker of oilseed rape, are members of such a large family of effectors. AvrLm10A and AvrLm10B are neighbouring genes, organized in divergent transcriptional orientation. Sequence searches within the L. maculans genome showed that AvrLm10A/AvrLm10B belong to a multigene family comprising five pairs of genes with a similar tail-to-tail organization. The two genes, in a pair, always had the same expression pattern and two expression profiles were distinguished, associated with the biotrophic colonization of cotyledons and/or petioles and stems. Of the two protein pairs further investigated, AvrLm10A_like1/AvrLm10B_like1 and AvrLm10A_like2/AvrLm10B_like2, the second one had the ability to physically interact, similarly to what was previously described for the AvrLm10A/AvrLm10B pair, and cross-interactions were also detected for two pairs. AvrLm10A homologues were identified in more than 30 Dothideomycete and Sordariomycete plant-pathogenic fungi. One of them, SIX5, is an effector from Fusarium oxysporum f. sp. lycopersici physically interacting with the avirulence effector Avr2. We found that AvrLm10A/SIX5 homologues were associated with at least eight distinct putative effector families, suggesting that AvrLm10A/SIX5 is able to cooperate with different effectors. These results point to a general role of the AvrLm10A/SIX5 proteins as "cooperating proteins", able to interact with diverse families of effectors whose encoding gene is co-regulated with the neighbouring AvrLm10A homologue.
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Affiliation(s)
- Nacera Talbi
- BIOGER, INRAEUniversité Paris‐SaclayPalaiseauFrance
| | - Like Fokkens
- Molecular Plant PathologyUniversity of AmsterdamAmsterdamNetherlands
- Present address:
Laboratory of PhytopathologyWageningen University and ResearchWageningenNetherlands
| | - Corinne Audran
- UMR LIPMEUniversité de Toulouse, INRAE, CNRSCastanet‐TolosanFrance
| | | | - Cécile Pouzet
- FRAIB‐TRI Imaging Platform Facilities, FR AIBUniversité de Toulouse, CNRSCastanet‐TolosanFrance
| | | | - Elise J. Gay
- BIOGER, INRAEUniversité Paris‐SaclayPalaiseauFrance
| | | | | | - Martijn Rep
- Molecular Plant PathologyUniversity of AmsterdamAmsterdamNetherlands
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Gautier A, Laval V, Faure S, Rouxel T, Balesdent MH. Polymorphism of Avirulence Genes and Adaptation to Brassica Resistance Genes Is Gene-Dependent in the Phytopathogenic Fungus Leptosphaeria maculans. PHYTOPATHOLOGY 2023; 113:1222-1232. [PMID: 36802873 DOI: 10.1094/phyto-12-22-0466-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The fungal phytopathogen Leptosphaeria maculans, which causes stem canker (blackleg) of rapeseed (Brassica napus), is mainly controlled worldwide by genetic resistance, which includes major resistance genes (Rlm). This model is one of those for which the highest number of avirulence genes (AvrLm) has been cloned. In many systems, including the L. maculans-B. napus interaction, intense use of resistance genes exerts strong selection pressure on the corresponding avirulent isolates, and the fungi may rapidly escape resistance through various molecular events which modify the avirulence genes. In the literature, the study of polymorphism at avirulence loci is often focused on single genes under selection pressure. In this study, we investigate allelic polymorphism at 11 avirulence loci in a French population of 89 L. maculans isolates collected on a trap cultivar in four geographic locations in the 2017-2018 cropping season. The corresponding Rlm genes have been (i) used for a long time, (ii) recently used, or (iii) unused in agricultural practice. The sequence data generated indicate an extreme diversity of situations. For example, genes submitted to an ancient selection may have either been deleted in populations (AvrLm1) or replaced by a single-nucleotide mutated virulent version (AvrLm2, AvrLm5-9). Genes that have never been under selection may either be nearly invariant (AvrLm6, AvrLm10A, AvrLm10B), exhibit rare deletions (AvrLm11, AvrLm14), or display a high diversity of alleles and isoforms (AvrLmS-Lep2). These data suggest that the evolutionary trajectory of avirulence/virulence alleles is gene-dependent and independent of selection pressure in L. maculans. [Formula: see text] Copyright © 2023 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)
- Angélique Gautier
- Université Paris-Saclay, INRAE, UR BIOGER, Bâtiment F, 22 Place de l'Agronomie, CS 80022, 91120 Palaiseau Cedex, France
| | - Valérie Laval
- Université Paris-Saclay, INRAE, UR BIOGER, Bâtiment F, 22 Place de l'Agronomie, CS 80022, 91120 Palaiseau Cedex, France
| | | | - Thierry Rouxel
- Université Paris-Saclay, INRAE, UR BIOGER, Bâtiment F, 22 Place de l'Agronomie, CS 80022, 91120 Palaiseau Cedex, France
| | - Marie-Hélène Balesdent
- Université Paris-Saclay, INRAE, UR BIOGER, Bâtiment F, 22 Place de l'Agronomie, CS 80022, 91120 Palaiseau Cedex, France
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Rocafort M, Bowen JK, Hassing B, Cox MP, McGreal B, de la Rosa S, Plummer KM, Bradshaw RE, Mesarich CH. The Venturia inaequalis effector repertoire is dominated by expanded families with predicted structural similarity, but unrelated sequence, to avirulence proteins from other plant-pathogenic fungi. BMC Biol 2022; 20:246. [PMID: 36329441 PMCID: PMC9632046 DOI: 10.1186/s12915-022-01442-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 10/17/2022] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Scab, caused by the biotrophic fungus Venturia inaequalis, is the most economically important disease of apples worldwide. During infection, V. inaequalis occupies the subcuticular environment, where it secretes virulence factors, termed effectors, to promote host colonization. Consistent with other plant-pathogenic fungi, many of these effectors are expected to be non-enzymatic proteins, some of which can be recognized by corresponding host resistance proteins to activate plant defences, thus acting as avirulence determinants. To develop durable control strategies against scab, a better understanding of the roles that these effector proteins play in promoting subcuticular growth by V. inaequalis, as well as in activating, suppressing, or circumventing resistance protein-mediated defences in apple, is required. RESULTS We generated the first comprehensive RNA-seq transcriptome of V. inaequalis during colonization of apple. Analysis of this transcriptome revealed five temporal waves of gene expression that peaked during early, mid, or mid-late infection. While the number of genes encoding secreted, non-enzymatic proteinaceous effector candidates (ECs) varied in each wave, most belonged to waves that peaked in expression during mid-late infection. Spectral clustering based on sequence similarity determined that the majority of ECs belonged to expanded protein families. To gain insights into function, the tertiary structures of ECs were predicted using AlphaFold2. Strikingly, despite an absence of sequence similarity, many ECs were predicted to have structural similarity to avirulence proteins from other plant-pathogenic fungi, including members of the MAX, LARS, ToxA and FOLD effector families. In addition, several other ECs, including an EC family with sequence similarity to the AvrLm6 avirulence effector from Leptosphaeria maculans, were predicted to adopt a KP6-like fold. Thus, proteins with a KP6-like fold represent another structural family of effectors shared among plant-pathogenic fungi. CONCLUSIONS Our study reveals the transcriptomic profile underpinning subcuticular growth by V. inaequalis and provides an enriched list of ECs that can be investigated for roles in virulence and avirulence. Furthermore, our study supports the idea that numerous sequence-unrelated effectors across plant-pathogenic fungi share common structural folds. In doing so, our study gives weight to the hypothesis that many fungal effectors evolved from ancestral genes through duplication, followed by sequence diversification, to produce sequence-unrelated but structurally similar proteins.
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Affiliation(s)
- Mercedes Rocafort
- Laboratory of Molecular Plant Pathology/Bioprotection Aotearoa, School of Agriculture and Environment, Massey University, Private Bag 11222, Palmerston North, 4442, New Zealand
| | - Joanna K Bowen
- The New Zealand Institute for Plant and Food Research Limited, Mount Albert Research Centre, Auckland, 1025, New Zealand
| | - Berit Hassing
- Laboratory of Molecular Plant Pathology/Bioprotection Aotearoa, School of Agriculture and Environment, Massey University, Private Bag 11222, Palmerston North, 4442, New Zealand
| | - Murray P Cox
- Bioprotection Aotearoa, School of Natural Sciences, Massey University, Private Bag 11222, Palmerston North, 4442, New Zealand
| | - Brogan McGreal
- The New Zealand Institute for Plant and Food Research Limited, Mount Albert Research Centre, Auckland, 1025, New Zealand
| | - Silvia de la Rosa
- Laboratory of Molecular Plant Pathology/Bioprotection Aotearoa, School of Agriculture and Environment, Massey University, Private Bag 11222, Palmerston North, 4442, New Zealand
| | - Kim M Plummer
- Department of Animal, Plant and Soil Sciences, La Trobe University, AgriBio, Centre for AgriBiosciences, La Trobe University, Bundoora, Victoria, 3086, Australia
| | - Rosie E Bradshaw
- Bioprotection Aotearoa, School of Natural Sciences, Massey University, Private Bag 11222, Palmerston North, 4442, New Zealand
| | - Carl H Mesarich
- Laboratory of Molecular Plant Pathology/Bioprotection Aotearoa, School of Agriculture and Environment, Massey University, Private Bag 11222, Palmerston North, 4442, New Zealand.
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10
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Poveda J, Rodríguez VM, Díaz-Urbano M, Sklenář F, Saati-Santamaría Z, Menéndez E, Velasco P. Endophytic fungi from kale (Brassica oleracea var. acephala) modify roots-glucosinolate profile and promote plant growth in cultivated Brassica species. First description of Pyrenophora gallaeciana. Front Microbiol 2022; 13:981507. [PMID: 36274741 PMCID: PMC9580329 DOI: 10.3389/fmicb.2022.981507] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 09/20/2022] [Indexed: 11/13/2022] Open
Abstract
Endophytic fungi of crops can promote plant growth through various mechanisms of action (i.e., improve nutrient uptake and nutrient use efficiency, and produce and modulate plant hormones). The genus Brassica includes important horticultural crops, which have been little studied in their interaction with endophytic fungi. Previously, four endophytic fungi were isolated from kale roots (Brassica oleracea var. acephala), with different benefits for their host, including plant growth promotion, cold tolerance, and induction of resistance to pathogens (Xanthomonas campestris) and pests (Mamestra brassicae). In the present work, the molecular and morphological identification of the four different isolates were carried out, describing them as the species Acrocalymma vagum, Setophoma terrestris, Fusarium oxysporum, and the new species Pyrenophora gallaeciana. In addition, using a representative crop of each Brassica U’s triangle species and various in vitro biochemical tests, the ability of these fungi to promote plant growth was described. In this sense, the four fungi used promoted the growth of B. rapa, B. napus, B. nigra, B. juncea, and B. carinata, possibly due to the production of auxins, siderophores, P solubilization or cellulase, xylanase or amylase activity. Finally, the differences in root colonization between the four endophytic fungi and two pathogens (Leptosphaeria maculans and Sclerotinia sclerotiorum) and the root glucosinolate profile were studied, at different times. In this way, how the presence of progoitrin in the roots reduces their colonization by endophytic and pathogenic fungi was determined, while the possible hydrolysis of sinigrin to fungicidal products controls the colonization of endophytic fungi, but not of pathogens.
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Affiliation(s)
- Jorge Poveda
- Institute for Multidisciplinary Research in Applied Biology (IMAB), Universidad Pública de Navarra, Pamplona, Spain
- *Correspondence: Jorge Poveda, ; Pablo Velasco,
| | - Víctor M. Rodríguez
- Group of Genetics, Breeding and Biochemistry of Brassicas, Mision Biologica de Galicia (MBG-CSIC), Pontevedra, Spain
| | - María Díaz-Urbano
- Group of Genetics, Breeding and Biochemistry of Brassicas, Mision Biologica de Galicia (MBG-CSIC), Pontevedra, Spain
| | - František Sklenář
- Laboratory of Fungal Genetics and Metabolism, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czechia
| | - Zaki Saati-Santamaría
- Laboratory of Fungal Genetics and Metabolism, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czechia
- Microbiology and Genetics Department and Institute for Agribiotechnology Research (CIALE), University of Salamanca, Salamanca, Spain
| | - Esther Menéndez
- Microbiology and Genetics Department and Institute for Agribiotechnology Research (CIALE), University of Salamanca, Salamanca, Spain
| | - Pablo Velasco
- Group of Genetics, Breeding and Biochemistry of Brassicas, Mision Biologica de Galicia (MBG-CSIC), Pontevedra, Spain
- *Correspondence: Jorge Poveda, ; Pablo Velasco,
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11
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Borhan MH, Van de Wouw AP, Larkan NJ. Molecular Interactions Between Leptosphaeria maculans and Brassica Species. ANNUAL REVIEW OF PHYTOPATHOLOGY 2022; 60:237-257. [PMID: 35576591 DOI: 10.1146/annurev-phyto-021621-120602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Canola is an important oilseed crop, providing food, feed, and fuel around the world. However, blackleg disease, caused by the ascomycete Leptosphaeria maculans, causes significant yield losses annually. With the recent advances in genomic technologies, the understanding of the Brassica napus-L. maculans interaction has rapidly increased, with numerous Avr and R genes cloned, setting this system up as a model organism for studying plant-pathogen associations. Although the B. napus-L. maculans interaction follows Flor's gene-for-gene hypothesis for qualitative resistance, it also puts some unique spins on the interaction. This review discusses the current status of the host-pathogen interaction and highlights some of the future gaps that need addressing moving forward.
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Affiliation(s)
- M Hossein Borhan
- Saskatoon Research and Development Centre, Agriculture and Agri-Food Canada, Saskatoon, Saskatchewan, Canada;
| | | | - Nicholas J Larkan
- Saskatoon Research and Development Centre, Agriculture and Agri-Food Canada, Saskatoon, Saskatchewan, Canada;
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12
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Van de Wouw AP, Sheedy EM, Ware AH, Marcroft S, Idnurm A. Independent breakdown events of the Brassica napus Rlm7 resistance gene including via the off-target impact of a dual-specificity avirulence interaction. MOLECULAR PLANT PATHOLOGY 2022; 23:997-1010. [PMID: 35249259 PMCID: PMC9190981 DOI: 10.1111/mpp.13204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 02/01/2022] [Accepted: 02/15/2022] [Indexed: 05/08/2023]
Abstract
Protection of many crops is achieved through the use of genetic resistance. Leptosphaeria maculans, the causal agent of blackleg disease of Brassica napus, has emerged as a model for understanding gene-for-gene interactions that occur between plants and pathogens. Whilst many of the characterized avirulence effector genes interact with a single resistance gene in the host, the AvrLm4-7 avirulence gene is recognized by two resistance genes, Rlm4 and Rlm7. Here, we report the "breakdown" of the Rlm7 resistance gene in Australia, under two different field conditions. The first, and more typical, breakdown probably resulted from widescale use of Rlm7-containing cultivars whereby selection has led to an increase of individuals in the L. maculans population that have undergone repeat-induced point (RIP) mutations at the AvrLm4-7 locus. This has rendered the AvrLm4-7 gene ineffective and therefore these isolates have become virulent towards both Rlm4 and Rlm7. The second, more atypical, situation was the widescale use of Rlm4 cultivars. Whilst a single-nucleotide polymorphism is the more common mechanism of virulence towards Rlm4, in this field situation, RIP mutations have been selected leading to the breakdown of resistance for both Rlm4 and Rlm7. This is an example of a resistance gene being rendered ineffective without having grown cultivars with the corresponding resistance gene due to the dual specificity of the avirulence gene. These findings highlight the value of pathogen surveillance in the context of expanded knowledge about potential complexities for Avr-R interactions for the deployment of appropriate resistance gene strategies.
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Affiliation(s)
| | | | | | | | - Alexander Idnurm
- School of BioSciencesUniversity of MelbourneParkvilleVictoriaAustralia
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13
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Lazar N, Mesarich CH, Petit-Houdenot Y, Talbi N, Li de la Sierra-Gallay I, Zélie E, Blondeau K, Gracy J, Ollivier B, Blaise F, Rouxel T, Balesdent MH, Idnurm A, van Tilbeurgh H, Fudal I. A new family of structurally conserved fungal effectors displays epistatic interactions with plant resistance proteins. PLoS Pathog 2022. [PMID: 35793393 DOI: 10.1101/2020.12.17.423041v1.full] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023] Open
Abstract
Recognition of a pathogen avirulence (AVR) effector protein by a cognate plant resistance (R) protein triggers a set of immune responses that render the plant resistant. Pathogens can escape this so-called Effector-Triggered Immunity (ETI) by different mechanisms including the deletion or loss-of-function mutation of the AVR gene, the incorporation of point mutations that allow recognition to be evaded while maintaining virulence function, and the acquisition of new effectors that suppress AVR recognition. The Dothideomycete Leptosphaeria maculans, causal agent of oilseed rape stem canker, is one of the few fungal pathogens where suppression of ETI by an AVR effector has been demonstrated. Indeed, AvrLm4-7 suppresses Rlm3- and Rlm9-mediated resistance triggered by AvrLm3 and AvrLm5-9, respectively. The presence of AvrLm4-7 does not impede AvrLm3 and AvrLm5-9 expression, and the three AVR proteins do not appear to physically interact. To decipher the epistatic interaction between these L. maculans AVR effectors, we determined the crystal structure of AvrLm5-9 and obtained a 3D model of AvrLm3, based on the crystal structure of Ecp11-1, a homologous AVR effector candidate from Fulvia fulva. Despite a lack of sequence similarity, AvrLm5-9 and AvrLm3 are structural analogues of AvrLm4-7 (structure previously characterized). Structure-informed sequence database searches identified a larger number of putative structural analogues among L. maculans effector candidates, including the AVR effector AvrLmS-Lep2, all produced during the early stages of oilseed rape infection, as well as among effector candidates from other phytopathogenic fungi. These structural analogues are named LARS (for Leptosphaeria AviRulence and Suppressing) effectors. Remarkably, transformants of L. maculans expressing one of these structural analogues, Ecp11-1, triggered oilseed rape immunity in several genotypes carrying Rlm3. Furthermore, this resistance could be suppressed by AvrLm4-7. These results suggest that Ecp11-1 shares a common activity with AvrLm3 within the host plant which is detected by Rlm3, or that the Ecp11-1 structure is sufficiently close to that of AvrLm3 to be recognized by Rlm3.
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Affiliation(s)
- Noureddine Lazar
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Carl H Mesarich
- Laboratory of Molecular Plant Pathology, School of Agriculture and Environment, Massey University, Palmerston North, New Zealand
| | | | - Nacera Talbi
- Université Paris-Saclay, INRAE, UR BIOGER, Thiverval-Grignon, France
| | - Ines Li de la Sierra-Gallay
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Emilie Zélie
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Karine Blondeau
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Jérôme Gracy
- CNRS UMR 5048, INSERM U1054, Centre de Biochimie Structurale, Université Montpellier, Montpellier, France
| | | | - Françoise Blaise
- Université Paris-Saclay, INRAE, UR BIOGER, Thiverval-Grignon, France
| | - Thierry Rouxel
- Université Paris-Saclay, INRAE, UR BIOGER, Thiverval-Grignon, France
| | | | - Alexander Idnurm
- School of BioSciences, The University of Melbourne, Melbourne, Australia
| | - Herman van Tilbeurgh
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Isabelle Fudal
- Université Paris-Saclay, INRAE, UR BIOGER, Thiverval-Grignon, France
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14
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Lazar N, Mesarich CH, Petit-Houdenot Y, Talbi N, Li de la Sierra-Gallay I, Zélie E, Blondeau K, Gracy J, Ollivier B, Blaise F, Rouxel T, Balesdent MH, Idnurm A, van Tilbeurgh H, Fudal I. A new family of structurally conserved fungal effectors displays epistatic interactions with plant resistance proteins. PLoS Pathog 2022; 18:e1010664. [PMID: 35793393 PMCID: PMC9292093 DOI: 10.1371/journal.ppat.1010664] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 07/18/2022] [Accepted: 06/10/2022] [Indexed: 12/31/2022] Open
Abstract
Recognition of a pathogen avirulence (AVR) effector protein by a cognate plant resistance (R) protein triggers a set of immune responses that render the plant resistant. Pathogens can escape this so-called Effector-Triggered Immunity (ETI) by different mechanisms including the deletion or loss-of-function mutation of the AVR gene, the incorporation of point mutations that allow recognition to be evaded while maintaining virulence function, and the acquisition of new effectors that suppress AVR recognition. The Dothideomycete Leptosphaeria maculans, causal agent of oilseed rape stem canker, is one of the few fungal pathogens where suppression of ETI by an AVR effector has been demonstrated. Indeed, AvrLm4-7 suppresses Rlm3- and Rlm9-mediated resistance triggered by AvrLm3 and AvrLm5-9, respectively. The presence of AvrLm4-7 does not impede AvrLm3 and AvrLm5-9 expression, and the three AVR proteins do not appear to physically interact. To decipher the epistatic interaction between these L. maculans AVR effectors, we determined the crystal structure of AvrLm5-9 and obtained a 3D model of AvrLm3, based on the crystal structure of Ecp11-1, a homologous AVR effector candidate from Fulvia fulva. Despite a lack of sequence similarity, AvrLm5-9 and AvrLm3 are structural analogues of AvrLm4-7 (structure previously characterized). Structure-informed sequence database searches identified a larger number of putative structural analogues among L. maculans effector candidates, including the AVR effector AvrLmS-Lep2, all produced during the early stages of oilseed rape infection, as well as among effector candidates from other phytopathogenic fungi. These structural analogues are named LARS (for Leptosphaeria AviRulence and Suppressing) effectors. Remarkably, transformants of L. maculans expressing one of these structural analogues, Ecp11-1, triggered oilseed rape immunity in several genotypes carrying Rlm3. Furthermore, this resistance could be suppressed by AvrLm4-7. These results suggest that Ecp11-1 shares a common activity with AvrLm3 within the host plant which is detected by Rlm3, or that the Ecp11-1 structure is sufficiently close to that of AvrLm3 to be recognized by Rlm3.
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Affiliation(s)
- Noureddine Lazar
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Carl H. Mesarich
- Laboratory of Molecular Plant Pathology, School of Agriculture and Environment, Massey University, Palmerston North, New Zealand
| | | | - Nacera Talbi
- Université Paris-Saclay, INRAE, UR BIOGER, Thiverval-Grignon, France
| | - Ines Li de la Sierra-Gallay
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Emilie Zélie
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Karine Blondeau
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Jérôme Gracy
- CNRS UMR 5048, INSERM U1054, Centre de Biochimie Structurale, Université Montpellier, Montpellier, France
| | | | - Françoise Blaise
- Université Paris-Saclay, INRAE, UR BIOGER, Thiverval-Grignon, France
| | - Thierry Rouxel
- Université Paris-Saclay, INRAE, UR BIOGER, Thiverval-Grignon, France
| | | | - Alexander Idnurm
- School of BioSciences, The University of Melbourne, Melbourne, Australia
| | - Herman van Tilbeurgh
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Isabelle Fudal
- Université Paris-Saclay, INRAE, UR BIOGER, Thiverval-Grignon, France
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15
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Xiang Neik T, Ghanbarnia K, Ollivier B, Scheben A, Severn‐Ellis A, Larkan NJ, Haddadi P, Fernando DWG, Rouxel T, Batley J, Borhan HM, Balesdent M. Two independent approaches converge to the cloning of a new Leptosphaeria maculans avirulence effector gene, AvrLmS-Lep2. MOLECULAR PLANT PATHOLOGY 2022; 23:733-748. [PMID: 35239989 PMCID: PMC8995059 DOI: 10.1111/mpp.13194] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 01/24/2022] [Accepted: 02/01/2022] [Indexed: 05/10/2023]
Abstract
Brassica napus (oilseed rape, canola) seedling resistance to Leptosphaeria maculans, the causal agent of blackleg (stem canker) disease, follows a gene-for-gene relationship. The avirulence genes AvrLmS and AvrLep2 were described to be perceived by the resistance genes RlmS and LepR2, respectively, present in B. napus 'Surpass 400'. Here we report cloning of AvrLmS and AvrLep2 using two independent methods. AvrLmS was cloned using combined in vitro crossing between avirulent and virulent isolates with sequencing of DNA bulks from avirulent or virulent progeny (bulked segregant sequencing). AvrLep2 was cloned using a biparental cross of avirulent and virulent L. maculans isolates and a classical map-based cloning approach. Taking these two approaches independently, we found that AvrLmS and AvrLep2 are the same gene. Complementation of virulent isolates with this gene confirmed its role in inducing resistance on Surpass 400, Topas-LepR2, and an RlmS-line. The gene, renamed AvrLmS-Lep2, encodes a small cysteine-rich protein of unknown function with an N-terminal secretory signal peptide, which is a common feature of the majority of effectors from extracellular fungal plant pathogens. The AvrLmS-Lep2/LepR2 interaction phenotype was found to vary from a typical hypersensitive response through intermediate resistance sometimes towards susceptibility, depending on the inoculation conditions. AvrLmS-Lep2 was nevertheless sufficient to significantly slow the systemic growth of the pathogen and reduce the stem lesion size on plant genotypes with LepR2, indicating the potential efficiency of this resistance to control the disease in the field.
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Affiliation(s)
- Ting Xiang Neik
- School of Biological SciencesUniversity of Western AustraliaPerthWestern AustraliaAustralia
| | - Kaveh Ghanbarnia
- Agriculture and Agri‐Food CanadaSaskatoon Research CenterSaskatoonSaskatchewanCanada
- Department of Plant SciencesUniversity of ManitobaWinnipegManitobaCanada
| | | | - Armin Scheben
- School of Biological SciencesUniversity of Western AustraliaPerthWestern AustraliaAustralia
- Simons Center for Quantitative Biology, Cold Spring Harbor LaboratoryCold Spring HarborNew YorkUSA
| | - Anita Severn‐Ellis
- School of Biological SciencesUniversity of Western AustraliaPerthWestern AustraliaAustralia
| | - Nicholas J. Larkan
- Agriculture and Agri‐Food CanadaSaskatoon Research CenterSaskatoonSaskatchewanCanada
- Armatus Genetics Inc.SaskatoonSaskatchewanCanada
| | - Parham Haddadi
- Agriculture and Agri‐Food CanadaSaskatoon Research CenterSaskatoonSaskatchewanCanada
| | | | - Thierry Rouxel
- Université Paris‐SaclayINRAEUR BIOGERThiverval‐GrignonFrance
| | - Jacqueline Batley
- School of Biological SciencesUniversity of Western AustraliaPerthWestern AustraliaAustralia
| | - Hossein M. Borhan
- Agriculture and Agri‐Food CanadaSaskatoon Research CenterSaskatoonSaskatchewanCanada
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16
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Alnajar D, von Tiedemann A, Koopmann B. Efficacy of Blackleg Major Resistance Genes in B. napus in Germany. Pathogens 2022; 11:461. [PMID: 35456136 PMCID: PMC9030727 DOI: 10.3390/pathogens11040461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 04/08/2022] [Accepted: 04/10/2022] [Indexed: 11/16/2022] Open
Abstract
Leptosphaeria maculans is one of the major pathogens of oilseed rape (B. napus). It causes blackleg disease, which accounts for significant yield losses worldwide. Using cultivars that harbor major resistance (R) genes is one of the most effective control methods. However, the efficacy of major R genes is related to the frequency of the corresponding avirulence (Avr) genes in a L. maculans population. In this paper, we report the Avr profiles of L. maculans populations and the ratio of its mating types in Northern and Central regions of Germany. Eleven Avr genes in five-hundred and seventy-four isolates were characterized either by applying cotyledon tests on a B. napus differential set or by amplifying avirulence gene-specific PCR markers. Fifty-two races were determined, among which the most dominant race was Avrlm6, -7, -11, AvrlepR1, -R2. Results showed that the resistance gene Rlm2 is 100% ineffective, some other major R genes such as Rlm1, Rlm3, Rlm4 and LepR3 are partially effective (with corresponding Avr frequencies ≤ 42%), while LepR1, LepR2, Rlm6, Rlm11 and Rlm7 can still provide relatively effective resistance in the German fields investigated (with corresponding Avr frequencies of 63-100%). Sexual reproduction is a factor that enhances the potential of L. maculans to evolve under selection pressure. Mating types of the L. maculans populations did not deviate from the ratio of 1:1 in the examined regions, indicating that sexual reproduction and ascospores play central roles in the L. maculans lifecycle. Overall, this study provides an important dataset for the establishment of a strategic plan to preserve the efficacies of major R genes in Germany by applying cultivar rotations of oilseed rape.
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Affiliation(s)
- Dima Alnajar
- Plant Pathology and Crop Protection, University of Goettingen, 37077 Goettingen, Germany; (A.v.T.); (B.K.)
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17
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Padmathilake KRE, Fernando WGD. Leptosphaeria maculans-Brassica napus Battle: A Comparison of Incompatible vs. Compatible Interactions Using Dual RNASeq. Int J Mol Sci 2022; 23:ijms23073964. [PMID: 35409323 PMCID: PMC8999614 DOI: 10.3390/ijms23073964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 03/28/2022] [Accepted: 03/30/2022] [Indexed: 02/05/2023] Open
Abstract
Leptosphaeria maculans causes blackleg disease, which is one of the most destructive diseases of canola (Brassica napus L.). Due to the erosion of the current resistance in B. napus, it is pivotal to introduce new resistant genotypes to the growers. This study evaluated the potential of Rlm7 gene as resistance to its corresponding avirulence AvrLm7 gene is abundant. The Rlm7 line was inoculated with L. maculans isolate with AvrLm7; UMAvr7; and the CRISPR/Cas9 knockout AvrLm7 mutant, umavr7, of the same isolate to cause incompatible and compatible interactions, respectively. Dual RNA-seq showed differential gene expressions in both interactions. High expressions of virulence-related pathogen genes-CAZymes, merops, and effector proteins after 7-dpi in compatible interactions but not in incompatible interaction—confirmed that the pathogen was actively virulent only in compatible interactions. Salicyclic and jasmonic acid biosynthesis and signaling-related genes, defense-related PR1 gene (GSBRNA2T00150001001), and GSBRNA2T00068522001 in the NLR gene family were upregulated starting as early as 1- and 3-dpi in the incompatible interaction and the high upregulation of those genes after 7-dpi in compatible interactions confirmed the early recognition of the pathogen by the host and control it by early activation of host defense mechanisms in the incompatible interaction.
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18
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Degrave A, Wagner M, George P, Coudard L, Pinochet X, Ermel M, Gay EJ, Fudal I, Moreno‐Rico O, Rouxel T, Balesdent M. A new avirulence gene of Leptosphaeria maculans, AvrLm14, identifies a resistance source in American broccoli (Brassica oleracea) genotypes. MOLECULAR PLANT PATHOLOGY 2021; 22:1599-1612. [PMID: 34467616 PMCID: PMC8578820 DOI: 10.1111/mpp.13131] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 08/09/2021] [Accepted: 08/11/2021] [Indexed: 05/19/2023]
Abstract
In many cultivated crops, sources of resistance to diseases are sparse and rely on introgression from wild relatives. Agricultural crops often are allopolyploids resulting from interspecific crosses between related species, which are sources of diversity for resistance genes. This is the case for Brassica napus (oilseed rape, canola), an interspecific hybrid between Brassica rapa (turnip) and Brassica oleracea (cabbage). B. napus has a narrow genetic basis and few effective resistance genes against stem canker (blackleg) disease, caused by the fungus Leptosphaeria maculans, are currently available. B. rapa diversity has proven to be a valuable source of resistance (Rlm, LepR) genes, while B. oleracea genotypes were mostly considered susceptible. Here we identified a new resistance source in B. oleracea genotypes from America, potentially effective against French L. maculans isolates under both controlled and field conditions. Genetic analysis of fungal avirulence and subsequent cloning and validation identified a new avirulence gene termed AvrLm14 and suggested a typical gene-for-gene interaction between AvrLm14 and the postulated Rlm14 gene. AvrLm14 shares all the usual characteristics of L. maculans avirulence genes: it is hosted in a genomic region enriched in transposable elements and heterochromatin marks H3K9me3, its expression is repressed during vegetative growth but shows a strong overexpression 5-9 days following cotyledon infection, and it encodes a small secreted protein enriched in cysteine residues with few matches in databases. Similar to the previously cloned AvrLm10-A, AvrLm14 contributes to reduce lesion size on susceptible cotyledons, pointing to a complex interplay between effectors promoting or reducing lesion development.
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Affiliation(s)
| | - Marine Wagner
- Université Paris‐SaclayINRAE, UMR BIOGERThiverval‐GrignonFrance
| | | | - Laurent Coudard
- Université Paris‐SaclayINRAE, UMR BIOGERThiverval‐GrignonFrance
| | - Xavier Pinochet
- TERRES INOVIA, campus INRA Agro ParisTechThiverval‐GrignonFrance
| | - Magali Ermel
- INRAE, Institut Agro, Univ Rennes, IGEPPLe RheuFrance
| | - Elise J. Gay
- Université Paris‐SaclayINRAE, UMR BIOGERThiverval‐GrignonFrance
| | - Isabelle Fudal
- Université Paris‐SaclayINRAE, UMR BIOGERThiverval‐GrignonFrance
| | | | - Thierry Rouxel
- Université Paris‐SaclayINRAE, UMR BIOGERThiverval‐GrignonFrance
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19
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Chen Q, Peng G, Kutcher R, Yu F. Genetic diversity and population structure of Leptosphaeria maculans isolates in Western Canada. J Genet Genomics 2021; 48:994-1006. [PMID: 34702671 DOI: 10.1016/j.jgg.2021.06.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 06/17/2021] [Accepted: 06/24/2021] [Indexed: 10/20/2022]
Abstract
Leptosphaeria maculans is a serious concern for canola production worldwide. For effective disease management, knowledge of the pathogen's genetic variability and population structure is a prerequisite. In this study, whole-genome sequencing was performed for 162 of 1590 L. maculans isolates collected in the years 2007-2008 and 2012-2014 in Western Canada. DNA variants in genome-wide and specific regions including avirulence (Avr) genes were characterized. A total of 31,870 high-quality polymorphic DNA variants were used to study L. maculans genetic diversity and population structure. Cluster analysis showed that 150 isolates were clustered into 2 main groups and 4 subgroups by DNA variants located in either Avr or small secreted protein-encoding genes and into 2 main groups and 6 subgroups by genome-wide variants. The analysis of nucleotide diversity and differentiation also confirmed genetic variation within a population and among populations. Principal component analysis with genome-wide variants showed that the isolates collected in 2012-2014 were more genetically diverse than those collected in 2007-2008. Population structure analysis discovered three distinct sub-populations. Although isolates from Saskatchewan and Alberta were of similar genetic composition, Manitoba isolates were highly diverse. Genome-wide association study detected DNA variants in genes AvrLm4-7, Lema_T86300, and Lema_T86310 associated with the years of collection.
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Affiliation(s)
- Qilin Chen
- Saskatoon Research and Development Centre, Agriculture and Agri-Food Canada, Saskatoon, Canada
| | - Gary Peng
- Saskatoon Research and Development Centre, Agriculture and Agri-Food Canada, Saskatoon, Canada
| | - Randy Kutcher
- Department of Plant Sciences, Crop Development Centre, University of SK, Saskatoon, SK, Canada
| | - Fengqun Yu
- Saskatoon Research and Development Centre, Agriculture and Agri-Food Canada, Saskatoon, Canada.
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20
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Jones DAB, Moolhuijzen PM, Hane JK. Remote homology clustering identifies lowly conserved families of effector proteins in plant-pathogenic fungi. Microb Genom 2021; 7. [PMID: 34468307 PMCID: PMC8715435 DOI: 10.1099/mgen.0.000637] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Plant diseases caused by fungal pathogens are typically initiated by molecular interactions between 'effector' molecules released by a pathogen and receptor molecules on or within the plant host cell. In many cases these effector-receptor interactions directly determine host resistance or susceptibility. The search for fungal effector proteins is a developing area in fungal-plant pathology, with more than 165 distinct confirmed fungal effector proteins in the public domain. For a small number of these, novel effectors can be rapidly discovered across multiple fungal species through the identification of known effector homologues. However, many have no detectable homology by standard sequence-based search methods. This study employs a novel comparison method (RemEff) that is capable of identifying protein families with greater sensitivity than traditional homology-inference methods, leveraging a growing pool of confirmed fungal effector data to enable the prediction of novel fungal effector candidates by protein family association. Resources relating to the RemEff method and data used in this study are available from https://figshare.com/projects/Effector_protein_remote_homology/87965.
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Affiliation(s)
- Darcy A B Jones
- Centre for Crop & Disease Management, School of Molecular & Life Sciences, Curtin University, Perth, Australia
| | - Paula M Moolhuijzen
- Centre for Crop & Disease Management, School of Molecular & Life Sciences, Curtin University, Perth, Australia
| | - James K Hane
- Centre for Crop & Disease Management, School of Molecular & Life Sciences, Curtin University, Perth, Australia.,Curtin Institute for Computation, Curtin University, Perth, Australia
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21
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Jiquel A, Gervais J, Geistodt‐Kiener A, Delourme R, Gay EJ, Ollivier B, Fudal I, Faure S, Balesdent M, Rouxel T. A gene-for-gene interaction involving a 'late' effector contributes to quantitative resistance to the stem canker disease in Brassica napus. THE NEW PHYTOLOGIST 2021; 231:1510-1524. [PMID: 33621369 PMCID: PMC8360019 DOI: 10.1111/nph.17292] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 02/15/2021] [Indexed: 05/19/2023]
Abstract
The control of stem canker disease of Brassica napus (rapeseed), caused by the fungus Leptosphaeria maculans is based largely on plant genetic resistance: single-gene specific resistance (Rlm genes) or quantitative, polygenic, adult-stage resistance. Our working hypothesis was that quantitative resistance partly obeys the gene-for-gene model, with resistance genes 'recognizing' fungal effectors expressed during late systemic colonization. Five LmSTEE (stem-expressed effector) genes were selected and placed under the control of the AvrLm4-7 promoter, an effector gene highly expressed at the cotyledon stage of infection, for miniaturized cotyledon inoculation test screening of a gene pool of 204 rapeseed genotypes. We identified a rapeseed genotype, 'Yudal', expressing hypersensitive response to LmSTEE98. The LmSTEE98-RlmSTEE98 interaction was further validated by inactivation of the LmSTEE98 gene with a CRISPR-Cas9 approach. Isolates with mutated versions of LmSTEE98 induced more severe stem symptoms than the wild-type isolate in 'Yudal'. This single-gene resistance was mapped in a 0.6 cM interval of the 'Darmor_bzh' × 'Yudal' genetic map. One typical gene-for-gene interaction contributes partly to quantitative resistance when L. maculans colonizes the stems of rapeseed. With numerous other effectors specific to stem colonization, our study provides a new route for resistance gene discovery, elucidation of quantitative resistance mechanisms and selection for durable resistance.
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Affiliation(s)
- Audren Jiquel
- INRAEAgroParisTechUMR BIOGERUniversité Paris‐SaclayAvenue Lucien Brétignières, BP 01Thiverval‐GrignonF‐78850France
- Euralis Semences6 Chemin des PanedautesMondonville31700France
| | - Julie Gervais
- INRAEAgroParisTechUMR BIOGERUniversité Paris‐SaclayAvenue Lucien Brétignières, BP 01Thiverval‐GrignonF‐78850France
| | - Aude Geistodt‐Kiener
- INRAEAgroParisTechUMR BIOGERUniversité Paris‐SaclayAvenue Lucien Brétignières, BP 01Thiverval‐GrignonF‐78850France
- Université Paris‐SaclayRoute de l'Orme aux MerisiersSaint‐Aubin91190France
| | | | - Elise J. Gay
- INRAEAgroParisTechUMR BIOGERUniversité Paris‐SaclayAvenue Lucien Brétignières, BP 01Thiverval‐GrignonF‐78850France
- Université Paris‐SaclayRoute de l'Orme aux MerisiersSaint‐Aubin91190France
| | - Bénédicte Ollivier
- INRAEAgroParisTechUMR BIOGERUniversité Paris‐SaclayAvenue Lucien Brétignières, BP 01Thiverval‐GrignonF‐78850France
| | - Isabelle Fudal
- INRAEAgroParisTechUMR BIOGERUniversité Paris‐SaclayAvenue Lucien Brétignières, BP 01Thiverval‐GrignonF‐78850France
| | | | - Marie‐Hélène Balesdent
- INRAEAgroParisTechUMR BIOGERUniversité Paris‐SaclayAvenue Lucien Brétignières, BP 01Thiverval‐GrignonF‐78850France
| | - Thierry Rouxel
- INRAEAgroParisTechUMR BIOGERUniversité Paris‐SaclayAvenue Lucien Brétignières, BP 01Thiverval‐GrignonF‐78850France
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Cornelsen J, Zou Z, Huang S, Parks P, Lange R, Peng G, Fernando WGD. Validating the Strategic Deployment of Blackleg Resistance Gene Groups in Commercial Canola Fields on the Canadian Prairies. FRONTIERS IN PLANT SCIENCE 2021; 12:669997. [PMID: 34177985 PMCID: PMC8222824 DOI: 10.3389/fpls.2021.669997] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 04/22/2021] [Indexed: 06/13/2023]
Abstract
Blackleg, caused by the fungal pathogen Leptosphaeria maculans, is a serious threat to canola (Brassica napus L.) production in western Canada. Crop scouting and extended crop rotation, along with the use of effective genetic resistance, have been key management practices available to mitigate the impact of the disease. In recent years, new pathogen races have reduced the effectiveness of some of the resistant cultivars deployed. Strategic deployment and rotation of major resistance (R) genes in cultivars have been used in France and Australia to help increase the longevity of blackleg resistance. Canada also introduced a grouping system in 2017 to identify blackleg R genes in canola cultivars. The main objective of this study was to examine and validate the concept of R gene deployment through monitoring the avirulence (Avr) profile of L. maculans population and disease levels in commercial canola fields within the Canadian prairies. Blackleg disease incidence and severity was collected from 146 cultivars from 53 sites across Manitoba, Saskatchewan, and Alberta in 2018 and 2019, and the results varied significantly between gene groups, which is likely influenced by the pathogen population. Isolates collected from spring and fall stubble residues were examined for the presence of Avr alleles AvrLm1, AvrLm2, AvrLm3, AvrLm4, AvrLm5, AvrLm6, AvrLm7, AvrLm9, AvrLm10, AvrLm11, AvrLepR1, AvrLepR2, AvrLep3, and AvrLmS using a set of differential host genotypes carrying known resistance genes or PCR-based markers. The Simpson's evenness index was very low, due to two dominant L. maculans races (AvrLm2-4-5-6-7-10-11 and AvrLm2-5-6-7-10-11) representing 49% of the population, but diversity of the population was high from the 35 L. maculans races isolated in Manitoba. AvrLm6 and AvrLm11 were found in all 254 L. maculans isolates collected in Manitoba. Knowledge of the blackleg disease levels in relation to the R genes deployed, along with the L. maculans Avr profile, helps to measure the effectiveness of genetic resistance.
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Affiliation(s)
- Justine Cornelsen
- Department of Plant Science, University of Manitoba, Winnipeg, MB, Canada
- Canola Council of Canada, Winnipeg, MB, Canada
| | - Zhongwei Zou
- Department of Plant Science, University of Manitoba, Winnipeg, MB, Canada
| | - Shuanglong Huang
- Department of Plant Science, University of Manitoba, Winnipeg, MB, Canada
| | - Paula Parks
- Department of Plant Science, University of Manitoba, Winnipeg, MB, Canada
| | | | - Gary Peng
- Agriculture and Agri-Food Canada (AAFC) Saskatoon, Saskatoon Research Centre, Saskatoon, SK, United States
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23
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Soyer JL, Clairet C, Gay EJ, Lapalu N, Rouxel T, Stukenbrock EH, Fudal I. Genome-wide mapping of histone modifications during axenic growth in two species of Leptosphaeria maculans showing contrasting genomic organization. Chromosome Res 2021; 29:219-236. [PMID: 34018080 PMCID: PMC8159818 DOI: 10.1007/s10577-021-09658-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 02/16/2021] [Accepted: 03/03/2021] [Indexed: 12/25/2022]
Abstract
Leptosphaeria maculans 'brassicae' (Lmb) and Leptosphaeria maculans 'lepidii' (Lml) are closely related phytopathogenic species that exhibit a large macrosynteny but contrasting genome structure. Lmb has more than 30% of repeats clustered in large repeat-rich regions, while the Lml genome has only a small amount of evenly distributed repeats. Repeat-rich regions of Lmb are enriched in effector genes, expressed during plant infection. The distinct genome structures of Lmb and Lml provide an excellent model for comparing the organization of pathogenicity genes in relation to the chromatin landscape in two closely related phytopathogenic fungi. Here, we performed chromatin immunoprecipitation (ChIP) during axenic culture, targeting histone modifications typical for heterochromatin or euchromatin, combined with transcriptomic analysis to analyze the influence of chromatin organization on gene expression. In both species, we found that facultative heterochromatin is enriched with genes lacking functional annotation, including numerous effector and species-specific genes. Notably, orthologous genes located in H3K27me3 domains are enriched with effector genes. Compared to other fungal species, including Lml, Lmb is distinct in having large H3K9me3 domains associated with repeat-rich regions that contain numerous species-specific effector genes. Discovery of these two distinctive heterochromatin landscapes now raises questions about their involvement in the regulation of pathogenicity, the dynamics of these domains during plant infection and the selective advantage to the fungus to host effector genes in H3K9me3 or H3K27me3 domains.
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Affiliation(s)
- Jessica L Soyer
- Université Paris-Saclay, INRAE, AgroParisTech, UMR BIOGER, 78850, Thiverval-Grignon, France.
- Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306, Plön, Germany.
- Christian-Albrechts University of Kiel, Am Botanischen Garten 1-9, 24118, Kiel, Germany.
| | - Colin Clairet
- Université Paris-Saclay, INRAE, AgroParisTech, UMR BIOGER, 78850, Thiverval-Grignon, France
| | - Elise J Gay
- Université Paris-Saclay, INRAE, AgroParisTech, UMR BIOGER, 78850, Thiverval-Grignon, France
| | - Nicolas Lapalu
- Université Paris-Saclay, INRAE, AgroParisTech, UMR BIOGER, 78850, Thiverval-Grignon, France
| | - Thierry Rouxel
- Université Paris-Saclay, INRAE, AgroParisTech, UMR BIOGER, 78850, Thiverval-Grignon, France
| | - Eva H Stukenbrock
- Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306, Plön, Germany
- Christian-Albrechts University of Kiel, Am Botanischen Garten 1-9, 24118, Kiel, Germany
| | - Isabelle Fudal
- Université Paris-Saclay, INRAE, AgroParisTech, UMR BIOGER, 78850, Thiverval-Grignon, France
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24
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Liu F, Zou Z, Peng G, Dilantha Fernando WG. Leptosphaeria maculans Isolates Reveal Their Allele Frequency in Western Canada. PLANT DISEASE 2021; 105:1440-1447. [PMID: 33100150 DOI: 10.1094/pdis-08-20-1838-re] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Blackleg, caused by Leptosphaeria maculans, is a major disease of canola in Canada, Australia, and Europe. For effective deployment of resistant varieties and disease management, it is crucial to understand the population structure of L. maculans. In this study, we analyzed L. maculans isolates from commercial fields in western Canada from 2014 to 2016 for the presence and frequency of avirulence (Avr) genes. A total of 1,584 isolates were examined for the presence of Avr genes AvrLm1, AvrLm2, AvrLm3, AvrLm4, AvrLm6, AvrLm7, AvrLm9, AvrLepR1, AvrLepR2, and AvrLmS via a set of differential host genotypes carrying known resistance genes and a PCR assay. Several Avr genes showed a higher frequency in the pathogen population, such as AvrLm6 and AvrLm7, which were present in >90% of isolates, whereas AvrLm3, AvrLm9, and AvrLepR2 showed frequencies of <10%. A total of 189 races (different combinations of Avr genes) were detected, with Avr-2-4-6-7-S, Avr-1-4-6-7, and Avr-2-4-6-7 as the three predominant races. When the effect of crop rotation was assessed, only a 3-year rotation showed a significantly higher frequency of AvrLm2 relative to shorter rotations. This study provides the information for producers to select effective canola varieties for blackleg management and for breeders to deploy new R genes in disease resistance breeding in western Canada.
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Affiliation(s)
- Fei Liu
- Department of Plant Science, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Zhongwei Zou
- Department of Plant Science, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Gary Peng
- Saskatoon Research and Development Centre, Agriculture and Agri-Food Canada, Saskatoon, Saskatchewan S7N 0X2, Canada
| | - W G Dilantha Fernando
- Department of Plant Science, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
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25
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Chavarro‐Carrero EA, Vermeulen JP, E. Torres D, Usami T, Schouten HJ, Bai Y, Seidl MF, Thomma BPHJ. Comparative genomics reveals the in planta-secreted Verticillium dahliae Av2 effector protein recognized in tomato plants that carry the V2 resistance locus. Environ Microbiol 2021; 23:1941-1958. [PMID: 33078534 PMCID: PMC8246953 DOI: 10.1111/1462-2920.15288] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 10/16/2020] [Accepted: 10/18/2020] [Indexed: 12/12/2022]
Abstract
Plant pathogens secrete effector molecules during host invasion to promote colonization. However, some of these effectors become recognized by host receptors to mount a defence response and establish immunity. Recently, a novel resistance was identified in wild tomato, mediated by the single dominant V2 locus, to control strains of the soil-borne vascular wilt fungus Verticillium dahliae that belong to race 2. With comparative genomics of race 2 strains and resistance-breaking race 3 strains, we identified the avirulence effector that activates V2 resistance, termed Av2. We identified 277 kb of race 2-specific sequence comprising only two genes encoding predicted secreted proteins that are expressed during tomato colonization. Subsequent functional analysis based on genetic complementation into race 3 isolates and targeted deletion from the race 1 isolate JR2 and race 2 isolate TO22 confirmed that one of the two candidates encodes the avirulence effector Av2 that is recognized in V2 tomato plants. Two Av2 allelic variants were identified that encode Av2 variants that differ by a single acid. Thus far, a role in virulence could not be demonstrated for either of the two variants.
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Affiliation(s)
| | - Jasper P. Vermeulen
- Laboratory of PhytopathologyWageningen University and ResearchWageningen6708 PBThe Netherlands
- Laboratory of Plant BreedingWageningen University and ResearchWageningen6708 PBThe Netherlands
| | - David E. Torres
- Laboratory of PhytopathologyWageningen University and ResearchWageningen6708 PBThe Netherlands
- Theoretical Biology and Bioinformatics Group, Department of BiologyUtrecht UniversityUtrechtThe Netherlands
| | - Toshiyuki Usami
- Graduate School of HorticultureChiba UniversityMatsudo, Chiba271‐8510Japan
| | - Henk J. Schouten
- Laboratory of Plant BreedingWageningen University and ResearchWageningen6708 PBThe Netherlands
| | - Yuling Bai
- Laboratory of Plant BreedingWageningen University and ResearchWageningen6708 PBThe Netherlands
| | - Michael F. Seidl
- Laboratory of PhytopathologyWageningen University and ResearchWageningen6708 PBThe Netherlands
- Theoretical Biology and Bioinformatics Group, Department of BiologyUtrecht UniversityUtrechtThe Netherlands
| | - Bart P. H. J. Thomma
- Laboratory of PhytopathologyWageningen University and ResearchWageningen6708 PBThe Netherlands
- Cluster of Excellence on Plant Sciences (CEPLAS)University of Cologne, Botanical InstituteCologneGermany
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Gay EJ, Soyer JL, Lapalu N, Linglin J, Fudal I, Da Silva C, Wincker P, Aury JM, Cruaud C, Levrel A, Lemoine J, Delourme R, Rouxel T, Balesdent MH. Large-scale transcriptomics to dissect 2 years of the life of a fungal phytopathogen interacting with its host plant. BMC Biol 2021; 19:55. [PMID: 33757516 PMCID: PMC7986464 DOI: 10.1186/s12915-021-00989-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 02/19/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND The fungus Leptosphaeria maculans has an exceptionally long and complex relationship with its host plant, Brassica napus, during which it switches between different lifestyles, including asymptomatic, biotrophic, necrotrophic, and saprotrophic stages. The fungus is also exemplary of "two-speed" genome organisms in the genome of which gene-rich and repeat-rich regions alternate. Except for a few stages of plant infection under controlled conditions, nothing is known about the genes mobilized by the fungus throughout its life cycle, which may last several years in the field. RESULTS We performed RNA-seq on samples corresponding to all stages of the interaction of L. maculans with its host plant, either alive or dead (stem residues after harvest) in controlled conditions or in field experiments under natural inoculum pressure, over periods of time ranging from a few days to months or years. A total of 102 biological samples corresponding to 37 sets of conditions were analyzed. We show here that about 9% of the genes of this fungus are highly expressed during its interactions with its host plant. These genes are distributed into eight well-defined expression clusters, corresponding to specific infection lifestyles or to tissue-specific genes. All expression clusters are enriched in effector genes, and one cluster is specific to the saprophytic lifestyle on plant residues. One cluster, including genes known to be involved in the first phase of asymptomatic fungal growth in leaves, is re-used at each asymptomatic growth stage, regardless of the type of organ infected. The expression of the genes of this cluster is repeatedly turned on and off during infection. Whatever their expression profile, the genes of these clusters are enriched in heterochromatin regions associated with H3K9me3 or H3K27me3 repressive marks. These findings provide support for the hypothesis that part of the fungal genes involved in niche adaptation is located in heterochromatic regions of the genome, conferring an extreme plasticity of expression. CONCLUSION This work opens up new avenues for plant disease control, by identifying stage-specific effectors that could be used as targets for the identification of novel durable disease resistance genes, or for the in-depth analysis of chromatin remodeling during plant infection, which could be manipulated to interfere with the global expression of effector genes at crucial stages of plant infection.
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Affiliation(s)
- Elise J Gay
- Université Paris-Saclay, INRAE, AgroParisTech, UMR BIOGER, 78850, Thiverval-Grignon, France
| | - Jessica L Soyer
- Université Paris-Saclay, INRAE, AgroParisTech, UMR BIOGER, 78850, Thiverval-Grignon, France
| | - Nicolas Lapalu
- Université Paris-Saclay, INRAE, AgroParisTech, UMR BIOGER, 78850, Thiverval-Grignon, France
| | - Juliette Linglin
- Université Paris-Saclay, INRAE, AgroParisTech, UMR BIOGER, 78850, Thiverval-Grignon, France
| | - Isabelle Fudal
- Université Paris-Saclay, INRAE, AgroParisTech, UMR BIOGER, 78850, Thiverval-Grignon, France
| | - Corinne Da Silva
- Génomique Métabolique, Genoscope, Institut François Jacob, CEA, CNRS, Université d'Evry, Université Paris-Saclay, 91057, Evry, France
| | - Patrick Wincker
- Génomique Métabolique, Genoscope, Institut François Jacob, CEA, CNRS, Université d'Evry, Université Paris-Saclay, 91057, Evry, France
| | - Jean-Marc Aury
- Génomique Métabolique, Genoscope, Institut François Jacob, CEA, CNRS, Université d'Evry, Université Paris-Saclay, 91057, Evry, France
| | - Corinne Cruaud
- Genoscope, Institut François Jacob, CEA, Université Paris-Saclay, Evry, France
| | - Anne Levrel
- INRAE, Institut Agro, Univ Rennes, IGEPP, 35653, Le Rheu, France
| | - Jocelyne Lemoine
- INRAE, Institut Agro, Univ Rennes, IGEPP, 35653, Le Rheu, France
| | - Regine Delourme
- INRAE, Institut Agro, Univ Rennes, IGEPP, 35653, Le Rheu, France
| | - Thierry Rouxel
- Université Paris-Saclay, INRAE, AgroParisTech, UMR BIOGER, 78850, Thiverval-Grignon, France
| | - Marie-Hélène Balesdent
- Université Paris-Saclay, INRAE, AgroParisTech, UMR BIOGER, 78850, Thiverval-Grignon, France.
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Inoue Y, Vy TTP, Tani D, Tosa Y. Suppression of wheat blast resistance by an effector of Pyricularia oryzae is counteracted by a host specificity resistance gene in wheat. THE NEW PHYTOLOGIST 2021; 229:488-500. [PMID: 32852846 DOI: 10.1111/nph.16894] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 08/05/2020] [Indexed: 06/11/2023]
Abstract
Wheat blast caused by the Triticum pathotype of Pyricularia oryzae poses a serious threat to wheat production in South America and Asia and is now becoming a pandemic disease. Here, we show that Rmg8, a promising wheat gene for resistance breeding, is suppressed by PWT4, an effector gene of P. oryzae, and in turn that the suppression is counteracted by Rwt4, a wheat gene recognizing PWT4. When PWT4 was introduced into a wheat blast isolate carrying AVR-Rmg8 (an avirulence gene corresponding to Rmg8), PWT4 suppressed wheat resistance conferred by Rmg8. PWT4 did not alter the expression of AVR-Rmg8, but higher expression of PWT4 led to more efficient suppression. This suppression was observed in rwt4 carriers, but not in Rwt4 carriers, indicating that it is counteracted by Rwt4. PWT4 was assumed to have been horizontally transferred from a weed-associated cryptic species, P. pennisetigena, to an Avena isolate of P. oryzae in Brazil. This implies a potential risk of the acquisition of PWT4 by the wheat blast fungus and the 'breakdown' of Rmg8. We suggest that Rmg8 should be introduced together with Rwt4 into a wheat cultivar when it is used for resistance breeding.
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Affiliation(s)
- Yoshihiro Inoue
- Graduate School of Agricultural Science, Kobe University, Kobe, 657-8501, Japan
- Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan
| | - Trinh Thi Phuoug Vy
- Graduate School of Agricultural Science, Kobe University, Kobe, 657-8501, Japan
| | - Daichi Tani
- Graduate School of Agricultural Science, Kobe University, Kobe, 657-8501, Japan
| | - Yukio Tosa
- Graduate School of Agricultural Science, Kobe University, Kobe, 657-8501, Japan
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28
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Cantila AY, Saad NSM, Amas JC, Edwards D, Batley J. Recent Findings Unravel Genes and Genetic Factors Underlying Leptosphaeria maculans Resistance in Brassica napus and Its Relatives. Int J Mol Sci 2020; 22:E313. [PMID: 33396785 PMCID: PMC7795555 DOI: 10.3390/ijms22010313] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 12/29/2020] [Accepted: 12/29/2020] [Indexed: 11/20/2022] Open
Abstract
Among the Brassica oilseeds, canola (Brassica napus) is the most economically significant globally. However, its production can be limited by blackleg disease, caused by the fungal pathogen Lepstosphaeria maculans. The deployment of resistance genes has been implemented as one of the key strategies to manage the disease. Genetic resistance against blackleg comes in two forms: qualitative resistance, controlled by a single, major resistance gene (R gene), and quantitative resistance (QR), controlled by numerous, small effect loci. R-gene-mediated blackleg resistance has been extensively studied, wherein several genomic regions harbouring R genes against L. maculans have been identified and three of these genes were cloned. These studies advance our understanding of the mechanism of R gene and pathogen avirulence (Avr) gene interaction. Notably, these studies revealed a more complex interaction than originally thought. Advances in genomics help unravel these complexities, providing insights into the genes and genetic factors towards improving blackleg resistance. Here, we aim to discuss the existing R-gene-mediated resistance, make a summary of candidate R genes against the disease, and emphasise the role of players involved in the pathogenicity and resistance. The comprehensive result will allow breeders to improve resistance to L. maculans, thereby increasing yield.
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Affiliation(s)
| | | | | | | | - Jacqueline Batley
- School of Biological Sciences, University of Western Australia, Perth, WA 6009, Australia; (A.Y.C.); (N.S.M.S.); (J.C.A.); (D.E.)
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Li J, Fokkens L, Conneely LJ, Rep M. Partial pathogenicity chromosomes in Fusarium oxysporum are sufficient to cause disease and can be horizontally transferred. Environ Microbiol 2020; 22:4985-5004. [PMID: 32452643 PMCID: PMC7818268 DOI: 10.1111/1462-2920.15095] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/13/2020] [Accepted: 05/21/2020] [Indexed: 01/05/2023]
Abstract
In Fusarium oxysporum f.sp. lycopersici, all effector genes reported so far - also called SIX genes - are located on a single accessory chromosome which is required for pathogenicity and can also be horizontally transferred to another strain. To narrow down the minimal region required for virulence, we selected partial pathogenicity chromosome deletion strains by fluorescence-assisted cell sorting of a strain in which the two arms of the pathogenicity chromosome were labelled with GFP and RFP respectively. By testing the virulence of these deletion mutants, we show that the complete long arm and part of the short arm of the pathogenicity chromosome are not required for virulence. In addition, we demonstrate that smaller versions of the pathogenicity chromosome can also be transferred to a non-pathogenic strain and they are sufficient to turn the non-pathogen into a pathogen. Surprisingly, originally non-pathogenic strains that had received a smaller version of the pathogenicity chromosome were much more aggressive than recipients with a complete pathogenicity chromosome. Whole genome sequencing analysis revealed that partial deletions of the pathogenicity chromosome occurred mainly close to repeats, and that spontaneous duplication of sequences in accessory regions is frequent both in chromosome deletion strains and in horizontal transfer strains.
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Affiliation(s)
- Jiming Li
- Molecular Plant PathologyUniversity of AmsterdamAmsterdam1098 XHThe Netherlands
| | - Like Fokkens
- Molecular Plant PathologyUniversity of AmsterdamAmsterdam1098 XHThe Netherlands
| | - Lee James Conneely
- Molecular Plant PathologyUniversity of AmsterdamAmsterdam1098 XHThe Netherlands
| | - Martijn Rep
- Molecular Plant PathologyUniversity of AmsterdamAmsterdam1098 XHThe Netherlands
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Li J, Cornelissen B, Rep M. Host-specificity factors in plant pathogenic fungi. Fungal Genet Biol 2020; 144:103447. [PMID: 32827756 DOI: 10.1016/j.fgb.2020.103447] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 08/14/2020] [Accepted: 08/15/2020] [Indexed: 01/18/2023]
Abstract
Fortunately, no fungus can cause disease on all plant species, and although some plant-pathogenic fungi have quite a broad host range, most are highly limited in the range of plant species or even cultivars that they cause disease in. The mechanisms of host specificity have been extensively studied in many plant-pathogenic fungi, especially in fungal pathogens causing disease on economically important crops. Specifically, genes involved in host specificity have been identified during the last few decades. In this overview, we describe and discuss these host-specificity genes. These genes encode avirulence (Avr) proteins, proteinaceous host-specific toxins or secondary metabolites. We discuss the genomic context of these genes, their expression, polymorphism, horizontal transfer and involvement in pathogenesis.
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Affiliation(s)
- Jiming Li
- Molecular Plant Pathology, University of Amsterdam, Amsterdam 1098 XH, the Netherlands
| | - Ben Cornelissen
- Molecular Plant Pathology, University of Amsterdam, Amsterdam 1098 XH, the Netherlands
| | - Martijn Rep
- Molecular Plant Pathology, University of Amsterdam, Amsterdam 1098 XH, the Netherlands.
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Zou Z, Liu F, Selin C, Fernando WGD. Generation and Characterization of a Virulent Leptosphaeria maculans Isolate Carrying a Mutated AvrLm7 Gene Using the CRISPR/Cas9 System. Front Microbiol 2020; 11:1969. [PMID: 32849487 PMCID: PMC7432424 DOI: 10.3389/fmicb.2020.01969] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 07/24/2020] [Indexed: 11/30/2022] Open
Abstract
Blackleg, caused by the fungal pathogen Leptosphaeria maculans, is the most important disease affecting canola (Brassica napus) crops worldwide. We employed the clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated (Cas) system to generate the mutant isolate umavr7 from a point mutation of the AvrLm7 coding region in a L. maculans isolate (UMAvr7). Reverse transcription PCR and transcriptome data confirmed that the AvrLm7 gene was knocked out in the mutant isolate. Pathogenicity tests indicated that umavr7 can cause large lesions on a set of Brassica differential genotypes that express different resistance (R) genes. Comparative pathogenicity tests between UMAvr7 (wild type) and umavr7 on the corresponding B. napus genotype 01-23-2-1 (with Rlm7) showed that umavr7 is a mutant isolate, producing large gray/green lesions on cotyledons. The pathogenicity of the mutant isolate was shifted from avirulent to virulent on the B. napus Rlm7 genotype. Therefore, this mutant is virulence on the identified resistant genes to blackleg disease in B. napus genotypes. Superoxide accumulated differently in cotyledons in response to infection with UMAvr7 and umavr7, especially in resistant B. napus genotype 01-23-2-1. Resistance/susceptibility was further evaluated on 123 B. napus genotypes with the mutant isolate, umavr7. Only 6 of the 123 genotypes showed resistance to umavr7. The identification of these six resistant B. napus genotypes will lead to further studies on the development of blackleg disease resistance through breeding and the identification of novel R genes.
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Affiliation(s)
- Zhongwei Zou
- Department of Plant Science, University of Manitoba, Winnipeg, MB, Canada
| | - Fei Liu
- Department of Plant Science, University of Manitoba, Winnipeg, MB, Canada
| | - Carrie Selin
- Department of Plant Science, University of Manitoba, Winnipeg, MB, Canada
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