caa a22 4500 467929114 CHVBK 20180406152938.0 cr unu---uuuuu 170328e20060101xx s 000 0 eng 10.1007/s10658-005-2104-0 doi (NATIONALLICENCE)springer-10.1007/s10658-005-2104-0 A Large-Scale Survey of Races of Leptosphaeria maculans Occurring on Oilseed Rape in France [Elektronische Daten] [Marie-Hélène Balesdent, Karine Louvard, Xavier Pinochet, Thierry Rouxel] Nine avirulence genes (AvrLm1-AvrLm9) were identified in Leptosphaeria maculans, the causal agent of stem canker of oilseed rape (OSR), combinations of which could theoretically generate up to 512 different races of the fungus. L.maculans displays a high evolutionary potential to adapt to novel resistance genes as illustrated by the Rlm1 breakdown in France, where virulent populations became prevalent within three growing seasons. An improved knowledge of the race structure of the fungal population is therefore needed to ensure a better use of available major resistance genes. The objective of this study was to characterise the L.maculans population structure in France using a large-scale, rationalised sample of isolates. Experimental fields, planted with "trap plants” harbouring no major resistance gene, were sown at 20 locations. Single-pycnidium isolates were collected from leaf lesions that developed in early autumn and 1797 isolates were genotyped at Avr loci. The frequency of AvrLm6 and AvrLm7 was higher than 99%, whereas avrLm2 and avrLm9 alleles were fixed in the population. AvrLm1, AvrLm4, AvrLm5 and AvrLm8 were polymorphic. AvrLm3 isolates were detected at a very low frequency (less than 1%). Only 11 races were identified in France, with one race prevalent, namely Av5-6-7-(8) (i.e. virulent on Rlm1, Rlm2, Rlm3, Rlm4 and Rlm9), representing around 65% of the population. Disparities between the locations sampled were evident at all scales analysed. Some virulent races, such as those harbouring avrLm5, were present before the introduction of the corresponding resistance gene in the commercial OSR crop. Springer, 2006 avirulence gene nationallicence blackleg disease nationallicence gene-for-gene relationship nationallicence Phoma lingam nationallicence resistance nationallicence Avr : avirulence nationallicence cv : cultivar nationallicence OSR : oilseed rape nationallicence R : resistance nationallicence Balesdent Marie-Hélène INRA, Unité PMDV, Route de Saint Cyr, 78026, Versailles Cedex, France aut Louvard Karine INRA, Unité PMDV, Route de Saint Cyr, 78026, Versailles Cedex, France aut Pinochet Xavier CETIOM (Centre Technique des Oléagineux Métropolitains), BP4, 78850, Thiverval-Grignon, France aut Rouxel Thierry INRA, Unité PMDV, Route de Saint Cyr, 78026, Versailles Cedex, France aut European Journal of Plant Pathology Kluwer Academic Publishers 114/1(2006-01-01), 53-65 0929-1873 114:1<53 2006 114 10658 https://doi.org/10.1007/s10658-005-2104-0 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10658-005-2104-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Balesdent Marie-Hélène INRA, Unité PMDV, Route de Saint Cyr, 78026, Versailles Cedex, France aut NATIONALLICENCE 700 1- Louvard Karine INRA, Unité PMDV, Route de Saint Cyr, 78026, Versailles Cedex, France aut NATIONALLICENCE 700 1- Pinochet Xavier CETIOM (Centre Technique des Oléagineux Métropolitains), BP4, 78850, Thiverval-Grignon, France aut NATIONALLICENCE 700 1- Rouxel Thierry INRA, Unité PMDV, Route de Saint Cyr, 78026, Versailles Cedex, France aut NATIONALLICENCE 773 0- European Journal of Plant Pathology Kluwer Academic Publishers 114/1(2006-01-01), 53-65 0929-1873 114:1<53 2006 114 10658 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer