Large-scale population survey of Leptosphaeria maculans in France highlights both on-going breakdowns and potentially effective resistance genes in oilseed rape.

Autor: Balesdent MH; Université Paris-Saclay, INRAE, UR Bioger, 22, Place de l'Agronomie, Palaiseau, 91120, France., Laval V; Université Paris-Saclay, INRAE, UR Bioger, 22, Place de l'Agronomie, Palaiseau, 91120, France., Noah JM; Université Paris-Saclay, INRAE, UR Bioger, 22, Place de l'Agronomie, Palaiseau, 91120, France., Bagot P; GEVES, Domaine de l'Anjouère, La Pouëze, 49370, Erdre en Anjou, France., Mousseau A; GEVES, Domaine de l'Anjouère, La Pouëze, 49370, Erdre en Anjou, France., Rouxel T; Université Paris-Saclay, INRAE, UR Bioger, 22, Place de l'Agronomie, Palaiseau, 91120, France.
Jazyk: angličtina
Zdroj: Pest management science [Pest Manag Sci] 2024 May; Vol. 80 (5), pp. 2426-2434. Date of Electronic Publication: 2023 Feb 18.
DOI: 10.1002/ps.7401
Abstrakt: 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.
(© 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.)
Databáze: MEDLINE
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