Crop and Pasture Science Crop and Pasture Science Society
Plant sciences, sustainable farming systems and food quality
RESEARCH ARTICLE

Changes in allele frequencies of avirulence genes in the blackleg fungus, Leptosphaeria maculans, over two decades in Australia

Angela P. Van de Wouw A B , Barbara J. Howlett A and Alexander Idnurm A
+ Author Affiliations
- Author Affiliations

A School of BioSciences, The University of Melbourne, Vic. 3010, Australia.

B Corresponding author. Email: apvdw2@unimelb.edu.au

Crop and Pasture Science - https://doi.org/10.1071/CP16411
Submitted: 1 November 2016  Accepted: 22 March 2017   Published online: 17 May 2017

Abstract

Cultivation of canola (oilseed rape, rapeseed; Brassica napus) in many parts of the world relies on the use of cultivars carrying resistance genes that recognise avirulence products of the major canola pathogen, Leptosphaeria maculans. However, widespread cultivation of plants with such resistance provides the potential for evolution of the pathogen population to overcome resistance by altering the proportion of avirulence v. virulence alleles. In this study, the frequencies of avirulence genes were measured for 2091 Australian isolates dating from the late 1980s to present. Frequencies of avirulence genes changed over time. Analysis of isolates from the Eyre Peninsula, where canola is intensively cultivated, indicated that changes in allele frequencies at the AvrLm1, AvrLm4 and AvrLm6 loci could be correlated with the widespread planting of cultivars carrying specific resistance genes. These data show that determining avirulence allele frequencies in L. maculans populations provides power to anticipate which cultivars will be most successful in future growing seasons.

Additional keywords: LepR3, rotation of resistance.


References

Balesdent MH, Barbetti MJ, Li H, Sivasithamparam K, Gout L, Rouxel T (2005) Analysis of Leptosphaeria maculans race structure in a worldwide collection of isolates. Phytopathology 95, 1061–1071.
Analysis of Leptosphaeria maculans race structure in a worldwide collection of isolates.CrossRef | 1:CAS:528:DC%2BD2MXhtVemt7jL&md5=eee2a33366e3706cfb548b921d51b926CAS |

Balesdent MH, Fudal I, Ollivier B, Bally P, Grandaubert J, Eber F, Chevre AM, Leflon M, Rouxel T (2013) The dispensable chromosome of Leptosphaeria maculans shelters an effector gene conferring avirulence towards Brassica rapa. New Phytologist 198, 887–898.
The dispensable chromosome of Leptosphaeria maculans shelters an effector gene conferring avirulence towards Brassica rapa.CrossRef | 1:CAS:528:DC%2BC3sXlvVyrs7g%3D&md5=568bd5c8b4b31b645a6773964a5c1408CAS |

Burton WA, Flood RF, Norton RM, Field B, Potts DA, Robertson MJ, Salisbury PA (2008) Identification of variability in phenological responses in canola-quality Brassica juncea for utilisation in Australian breeding programs. Australian Journal of Agricultural Research 59, 874–881.
Identification of variability in phenological responses in canola-quality Brassica juncea for utilisation in Australian breeding programs.CrossRef |

Cozijnsen AJ, Howlett BJ (2003) Characterisation of the mating-type locus of the plant pathogenic ascomycete Leptosphaeria maculans. Current Genetics 43, 351–357.
Characterisation of the mating-type locus of the plant pathogenic ascomycete Leptosphaeria maculans.CrossRef | 1:CAS:528:DC%2BD3sXltFCntLk%3D&md5=57662c70359372a0756e89895aa0b10eCAS |

Delourme R, Pilet-Nayel ML, Archipiano M, Horvais R, Tanguy X, Rouxel T, Brun H, Renard M, Balesdent MH (2004) A cluster of major specific resistance genes to Leptosphaeria maculans in Brassica napus. Phytopathology 94, 578–583.
A cluster of major specific resistance genes to Leptosphaeria maculans in Brassica napus.CrossRef | 1:CAS:528:DC%2BD2cXltFynurs%3D&md5=6faddd726e5cabb60afeec4005237f85CAS |

Delourme R, Chevre AM, Brun H, Rouxel T, Balesdent MH, Dias JS, Salisbury P, Renard M, Rimmer SR (2006) Major gene and polygenic resistance to Leptosphaeria maculans in oilseed rape (Brassica napus). European Journal of Plant Pathology 114, 41–52.
Major gene and polygenic resistance to Leptosphaeria maculans in oilseed rape (Brassica napus).CrossRef |

Dilmaghani A, Balesdent M, Didier JP, Wu C, Davey J, Barbetti M, Li H, Moreno-Rico O, Phillips D, Despeghel JP, Vincenot L, Gout L, Rouxel T (2009) The Leptosphaeria maculans–Leptosphaeria biglobosa species complex in the American continent. Plant Pathology 58, 1044–1058.
The Leptosphaeria maculans–Leptosphaeria biglobosa species complex in the American continent.CrossRef |

Flor HH (1955) Host–parasite interactions in flax rust—its genetic and other implications. Phytopathology 45, 680–685.

Fudal I, Ross S, Gout L, Blaise F, Kuhn ML, Eckert MR, Cattolico L, Bernard-Samain S, Balesdent MH, Rouxel T (2007) Heterochromatin-like regions as ecological niches for avirulence genes in the Leptosphaeria maculans genome: map-based cloning of AvrLm6. Molecular Plant-Microbe Interactions 20, 459–470.
Heterochromatin-like regions as ecological niches for avirulence genes in the Leptosphaeria maculans genome: map-based cloning of AvrLm6.CrossRef | 1:CAS:528:DC%2BD2sXjsVyksb4%3D&md5=17608254413efee2aeb5d2377aefdb43CAS |

Ghanbarnia K, Fudal I, Larkan NJ, Links MG, Balesdent M, Profotova B, Fernando DWG, Rouxel T, Borhan H (2015) Rapid identification of the Leptosphaeria maculans avirulence gene AvrLm2 using an intraspecific comparative genomics approach. Molecular Plant Pathology 16, 699–709.
Rapid identification of the Leptosphaeria maculans avirulence gene AvrLm2 using an intraspecific comparative genomics approach.CrossRef | 1:CAS:528:DC%2BC2MXht1CktbzP&md5=3207b3ff1decd4794dd20159c54b5c89CAS |

Gout L, Fudal I, Kuhn ML, Blaise F, Eckert M, Cattolico L, Balesdent MH, Rouxel T (2006) Lost in the middle of nowhere: the AvrLm1 avirulence gene of the Dothideomycete Leptosphaeria maculans. Molecular Microbiology 60, 67–80.
Lost in the middle of nowhere: the AvrLm1 avirulence gene of the Dothideomycete Leptosphaeria maculans.CrossRef | 1:CAS:528:DC%2BD28Xjsleht7Y%3D&md5=7f098dfe24d7c9c97f26eb08aef64657CAS |

Huang YJ, Evans N, Li ZQ, Eckert M, Chevre AM, Renard M, Fitt BDL (2006) Temperature and leaf wetness duration affect phenotypic expression of Rlm6-mediated resistance to Leptosphaeria maculans in Brassica napus. New Phytologist 170, 129–141.
Temperature and leaf wetness duration affect phenotypic expression of Rlm6-mediated resistance to Leptosphaeria maculans in Brassica napus.CrossRef |

Huang YJ, Balesdent MH, Li ZQ, Evans N, Rouxel T, Fitt BDL (2010) Fitness cost of virulence differs between the AvrLm1 and AvrLm4 loci in Leptosphaeria maculans (phoma stem canker of oilseed rape). European Journal of Plant Pathology 126, 279–291.
Fitness cost of virulence differs between the AvrLm1 and AvrLm4 loci in Leptosphaeria maculans (phoma stem canker of oilseed rape).CrossRef |

Khush GS (2001) Green revolution: the way forward. Nature Reviews. Genetics 2, 815–822.
Green revolution: the way forward.CrossRef | 1:CAS:528:DC%2BD38Xmt1Wgu7w%3D&md5=88b6258a769bcc4c7563e5e0688d2e3cCAS |

Koch E, Song K, Osborn TC, Williams PH (1991) Relationship between pathogenicity and phylogeny based on restriction fragment length polymorphism in Leptosphaeria maculans. Molecular Plant-Microbe Interactions 4, 341–349.
Relationship between pathogenicity and phylogeny based on restriction fragment length polymorphism in Leptosphaeria maculans.CrossRef | 1:CAS:528:DyaK38XhsVGnsL0%3D&md5=36c7d24be02ecf026433f35590b8fd5bCAS |

Kutcher HR, Balesdent M, Rimmer SR, Rouxel T, Chevre AM, Delourme R, Brun H (2010) Frequency of avirulence genes in Leptospaheria maculans in western Canada. Canadian Journal of Plant Pathology 32, 77–85.
Frequency of avirulence genes in Leptospaheria maculans in western Canada.CrossRef | 1:CAS:528:DC%2BC3cXltF2mtL0%3D&md5=25b72b95f7fe7033c7de63ac6e26b0eaCAS |

Larkan NJ, Lydiate DJ, Parkin IA, Nelson MN, Epp DJ, Cowling WA, Rimmer SR, Borhan MH (2013) The Brassica napus blackleg resistance gene LepR3 encodes a receptor-like protein triggered by the Leptosphaeria maculans effector AVRLM1. New Phytologist 197, 595–605.
The Brassica napus blackleg resistance gene LepR3 encodes a receptor-like protein triggered by the Leptosphaeria maculans effector AVRLM1.CrossRef | 1:CAS:528:DC%2BC38XhvVynsrrN&md5=a88938393eb0faae545ee4c32b8e7133CAS |

Larkan NJ, Ma L, Borhan H (2015) The Brassica napus receptor-like protein RLM2 is encoded by a second allele of the LepR3/Rlm2 blackleg resistance locus. Plant Biotechnology Journal 13, 983–992.
The Brassica napus receptor-like protein RLM2 is encoded by a second allele of the LepR3/Rlm2 blackleg resistance locus.CrossRef | 1:CAS:528:DC%2BC2MXhtl2murjM&md5=74eebfc0f5ce202b9e254b8c3a71f008CAS |

Liban SH, Cross DJ, Kutcher HR, Peng G, Fernando DWG (2016) Race structure and frequency of avirulence genes in the western Canadian Leptosphaeria maculans pathogen population, the causal agent of blackleg in brassica species. Plant Pathology 65, 1161–1169.
Race structure and frequency of avirulence genes in the western Canadian Leptosphaeria maculans pathogen population, the causal agent of blackleg in brassica species.CrossRef | 1:CAS:528:DC%2BC28Xht1yht7nK&md5=18674ce689f066f0fb10b986891fc9d4CAS |

Marcroft SJ, Elliott VL, Cozijnsen AJ, Salisbury PA, Howlett BJ, Van de Wouw AP (2012a) Identifying resistance genes to Leptosphaeria maculans in Australian Brassica napus cultivars based on reactions to isolates with known avirulence genotypes. Crop & Pasture Science 63, 338–350.
Identifying resistance genes to Leptosphaeria maculans in Australian Brassica napus cultivars based on reactions to isolates with known avirulence genotypes.CrossRef | 1:CAS:528:DC%2BC38XptVWltL0%3D&md5=946c3ff5ed10f42960d8d07ca923d80eCAS |

Marcroft SJ, Van de Wouw AP, Salisbury PA, Potter TD, Howlett BJ (2012b) Rotation of canola (Brassica napus) cultivars with different complements of blackleg resistance genes decreases disease severity. Plant Pathology 61, 934–944.
Rotation of canola (Brassica napus) cultivars with different complements of blackleg resistance genes decreases disease severity.CrossRef | 1:CAS:528:DC%2BC38XhslSkurjJ&md5=7133e66bf40c3fe505b1fe971f67496bCAS |

McDonald BA, Linde C (2002) Pathogen population genetics, evolutionary potential, and durable resistance. Annual Review of Phytopathology 40, 349–379.
Pathogen population genetics, evolutionary potential, and durable resistance.CrossRef | 1:CAS:528:DC%2BD38Xos1Cltbg%3D&md5=23ccd90e8bb1f92b3aa9067a51063c92CAS |

Parlange F, Daverdin G, Fudal I, Kuhn ML, Balesdent MH, Blaise F, Grezes-Besset B, Rouxel T (2009) Leptosphaeria maculans avirulence gene AvrLm4-7 confers a dual recognition specificity by the Rlm4 and Rlm7 resistance genes of oilseed rape, and circumvents Rlm4-mediated recognition through a single amino acid change. Molecular Microbiology 71, 851–863.
Leptosphaeria maculans avirulence gene AvrLm4-7 confers a dual recognition specificity by the Rlm4 and Rlm7 resistance genes of oilseed rape, and circumvents Rlm4-mediated recognition through a single amino acid change.CrossRef | 1:CAS:528:DC%2BD1MXivFaqtb0%3D&md5=bb4486d4b05c11fff01bc085f861aa18CAS |

Plissonneau C, Daverdin G, Ollivier B, Blaise F, Degrave A, Fudal I, Rouxel T, Balesdent M (2016) A game of hide and seek between avirulence genes AvrLm4-7 and AvrLm3 in Leptosphaeria maculans. New Phytologist 209, 1613–1624.
A game of hide and seek between avirulence genes AvrLm4-7 and AvrLm3 in Leptosphaeria maculans.CrossRef | 1:CAS:528:DC%2BC28Xit12msbs%3D&md5=444065c9e4797e9845a5c37ee1f83232CAS |

Rouxel T, Grandaubert J, Hane JK, Hoede C, van de Wouw AP, Couloux A, Dominguez V, Anthouard V, Bally P, Bourras S, Cozijnsen AJ, Ciuffetti LM, Degrave A, Dilmaghani A, Duret L, Fudal I, Goodwin SB, Gout L, Glaser N, Linglin J, Kema GH, Lapalu N, Lawrence CB, May K, Meyer M, Ollivier B, Poulain J, Schoch CL, Simon A, Spatafora JW, Stachowiak A, Turgeon BG, Tyler BM, Vincent D, Weissenbach J, Amselem J, Quesneville H, Oliver RP, Wincker P, Balesdent MH, Howlett BJ (2011) Effector diversification within compartments of the Leptosphaeria maculans genome affected by Repeat-Induced Point mutations. Nature Communications 2, art202
Effector diversification within compartments of the Leptosphaeria maculans genome affected by Repeat-Induced Point mutations.CrossRef |

Sexton AC, Howlett BJ (2000) Characterisation of a cyanide hydratase gene in the phytopathogenic fungus Leptosphaeria maculans. Molecular & General Genetics 263, 463–470.
Characterisation of a cyanide hydratase gene in the phytopathogenic fungus Leptosphaeria maculans.CrossRef | 1:CAS:528:DC%2BD3cXjsFeqt7w%3D&md5=acd70f9c54db4d8700dab1c6808fc264CAS |

Sprague SJ, Marcroft SJ, Hayden HL, Howlett BJ (2006a) Major gene resistance to blackleg in Brassica napus overcome within three years of commercial production in southeastern Australia. Plant Disease 90, 190–198.
Major gene resistance to blackleg in Brassica napus overcome within three years of commercial production in southeastern Australia.CrossRef |

Sprague SJ, Balesdent MH, Brun H, Hayden HL, Marcroft SJ, Pinochet X, Rouxel T, Howlett BJ (2006b) Major gene resistance in Brassica napus (oilseed rape) is overcome by changes in virulence of populations of Leptosphaeria maculans in France and Australia. European Journal of Plant Pathology 114, 33–40.
Major gene resistance in Brassica napus (oilseed rape) is overcome by changes in virulence of populations of Leptosphaeria maculans in France and Australia.CrossRef |

Sprague SJ, Kirkegaard JA, Dove H, Graham JM, McDonald SE, Kelman WM (2015) Integrating dual-purpose wheat and canola into high-rainfall livestock systems in south-eastern Australia. Crop & Pasture Science 66, 365–376.
Integrating dual-purpose wheat and canola into high-rainfall livestock systems in south-eastern Australia.CrossRef |

Stukenbrock EH, McDonald BA (2009) Population genetics of fungal and oomycete effectors involved in gene-for-gene interactions. Molecular Plant-Microbe Interactions 22, 371–380.
Population genetics of fungal and oomycete effectors involved in gene-for-gene interactions.CrossRef | 1:CAS:528:DC%2BD1MXjs1OqsLg%3D&md5=a547dac54833ef9c92aa38df5ae333ecCAS |

Van de Wouw AP, Howlett BJ (2012) Estimating frequencies of virulent isolates in field populations of a plant pathogenic fungus, Leptosphaeria maculans, using high-throughput pyrosequencing. Journal of Applied Microbiology 113, 1145–1153.
Estimating frequencies of virulent isolates in field populations of a plant pathogenic fungus, Leptosphaeria maculans, using high-throughput pyrosequencing.CrossRef | 1:STN:280:DC%2BC38fivVOgsQ%3D%3D&md5=194595ca309fdc08a1918bd6538eb137CAS |

Van de Wouw AP, Marcroft SJ, Barbetti MJ, Hua L, Salisbury PA, Gout L, Rouxel T, Howlett BJ, Balesdent MH (2009) Dual control of avirulence in Leptosphaeria maculans towards a Brassica napus cultivar with ‘sylvestris-derived’ resistance suggests involvement of two resistance genes. Plant Pathology 58, 305–313.
Dual control of avirulence in Leptosphaeria maculans towards a Brassica napus cultivar with ‘sylvestris-derived’ resistance suggests involvement of two resistance genes.CrossRef |

Van de Wouw AP, Cozijnsen AJ, Hane JK, Brunner PC, McDonald BA, Oliver RP, Howlett BJ (2010) Evolution of linked avirulence effectors in Leptosphaeria maculans is affected by genomic environment and exposure to resistance genes in host plants. PLoS Pathogens 6, e1001180
Evolution of linked avirulence effectors in Leptosphaeria maculans is affected by genomic environment and exposure to resistance genes in host plants.CrossRef |

Van de Wouw AP, Elliott CE, Howlett BJ (2014a) Transformation of fungal isolates with avirulence genes provides tools for identification of corresponding resistance genes in the host plant. European Journal of Plant Pathology 140, 875–882.
Transformation of fungal isolates with avirulence genes provides tools for identification of corresponding resistance genes in the host plant.CrossRef | 1:CAS:528:DC%2BC2cXhtlarsbzK&md5=7d8316a2496595491f54ba64fbb89014CAS |

Van de Wouw AP, Marcroft SJ, Ware A, Lindbeck K, Khangura R, Howlett BJ (2014b) Breakdown of resistance to the fungal disease, blackleg, is averted in commercial canola (Brassica napus) crops in Australia. Field Crops Research 166, 144–151.
Breakdown of resistance to the fungal disease, blackleg, is averted in commercial canola (Brassica napus) crops in Australia.CrossRef |

Van de Wouw AP, Lowe RGT, Elliott CE, Dubois DJ, Howlett BJ (2014c) An avirulence gene, AvrLmJ1, from the blackleg fungus, Leptosphaeria maculans, confers avirulence to Brassica juncea cultivars. Molecular Plant Pathology 15, 523–530.
An avirulence gene, AvrLmJ1, from the blackleg fungus, Leptosphaeria maculans, confers avirulence to Brassica juncea cultivars.CrossRef | 1:CAS:528:DC%2BC2cXnslCksr8%3D&md5=48104cc4243bee16bcf0e91dcb016fdaCAS |

Van de Wouw AP, Marcroft SJ, Howlett BJ (2016) Blackleg disease of canola in Australia. Crop & Pasture Science 67, 273–282.
Blackleg disease of canola in Australia.CrossRef |



Export Citation