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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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Chong NF, Van de Wouw AP, Idnurm A. The ilv2 gene, encoding acetolactate synthase for branched chain amino acid biosynthesis, is required for plant pathogenicity by Leptosphaeria maculans. Mol Biol Rep 2024; 51:682. [PMID: 38796647 PMCID: PMC11127833 DOI: 10.1007/s11033-024-09620-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Accepted: 05/07/2024] [Indexed: 05/28/2024]
Abstract
BACKGROUND Control of blackleg disease of canola caused by the fungus Leptosphaeria maculans relies on strategies such as the inhibition of growth with fungicides. However, other chemicals are used during canola cultivation, including fertilizers and herbicides. There is widespread use of herbicides that target the acetolactate synthase (ALS) enzyme involved in branched chain amino acid synthesis and low levels of these amino acids within leaves of Brassica species. In L. maculans the ilv2 gene encodes ALS and thus ALS-inhibiting herbicides may inadvertently impact the fungus. METHODS AND RESULTS Here, the impact of a commercial herbicide targeting ALS and mutation of the homologous ilv2 gene in L. maculans was explored. Exposure to herbicide had limited impact on growth in vitro but reduced lesion sizes in plant disease experiments. Furthermore, the mutation of the ilv2 gene via CRISPR-Cas9 gene editing rendered the fungus non-pathogenic. CONCLUSION Herbicide applications can influence disease outcome, but likely to a minor extent.
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Affiliation(s)
- Nicholas F Chong
- School of BioSciences, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Angela P Van de Wouw
- School of BioSciences, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Alexander Idnurm
- School of BioSciences, The University of Melbourne, Melbourne, VIC, 3010, Australia.
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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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Gayacharan, Parida SK, Mondal N, Yadav R, Vishwakarma H, Rana JC. Mining legume germplasm for genetic gains: An Indian perspective. Front Genet 2023; 14:996828. [PMID: 36816034 PMCID: PMC9933516 DOI: 10.3389/fgene.2023.996828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 01/05/2023] [Indexed: 01/24/2023] Open
Abstract
Legumes play a significant role in food and nutritional security and contribute to environmental sustainability. Although legumes are highly beneficial crops, it has not yet been possible to enhance their yield and production to a satisfactory level. Amid a rising population and low yield levels, per capita average legume consumption in India has fallen by 71% over the last 50 years, and this has led to protein-related malnutrition in a large segment of the Indian population, especially women and children. Several factors have hindered attempts to achieve yield enhancement in grain legumes, including biotic and abiotic pressures, a lack of good ideotypes, less amenability to mechanization, poorer responsiveness to fertilizer input, and a poor genetic base. Therefore, there is a need to mine the approximately 0.4 million ex situ collections of legumes that are being conserved in gene banks globally for identification of ideal donors for various traits. The Indian National Gene Bank conserves over 63,000 accessions of legumes belonging to 61 species. Recent initiatives have been undertaken in consortia mode with the aim of unlocking the genetic potential of ex situ collections and conducting large-scale germplasm characterization and evaluation analyses. We assume that large-scale phenotyping integrated with omics-based science will aid the identification of target traits and their use to enhance genetic gains. Additionally, in cases where the genetic base of major legumes is narrow, wild relatives have been evaluated, and these are being exploited through pre-breeding. Thus far, >200 accessions of various legumes have been registered as unique donors for various traits of interest.
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Affiliation(s)
- Gayacharan
- ICAR-National Bureau of Plant Genetic Resources, New Delhi, India
| | - Swarup K. Parida
- DBT-National Institute of Plant Genome Research, New Delhi, India
| | - Nupur Mondal
- Shivaji College, University of Delhi, New Delhi, India
| | - Rashmi Yadav
- ICAR-National Bureau of Plant Genetic Resources, New Delhi, India
| | | | - Jai C. Rana
- Alliance of Bioversity International and CIAT, India Office, National Agricultural Science Complex, New Delhi, India
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