Screening and identification of resistance to Leptosphaeria maculans (stem canker) in Brassica napus accessions}

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• 作者：Rouxel ; Thierry ; Willner ; Evelin ; Coudard ; Laurent ; Balesdent ; Marie H&eacute ; lè ; ne
• 关键词：avirulence ; blackleg disease ; field resistance ; gene ; for ; gene ; Phoma lingam ; specific resistance
• 刊名：Euphytica
• 出版年：2003
• 出版时间：2003
• 年：2003
• 卷：133
• 期：2
• 页码：219-231
• 全文大小：130 KB
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Life Sciences
  Plant Physiology
  Plant Sciences
  Ecology
  
• 出版者：Springer Netherlands
• ISSN：1573-5060

文摘

The occurrence of race-specific resistancegenes to the stem canker fungus, Leptosphaeria maculans, was analysed in453 accessions of B. napus, mainlyoriginating from the Institut fürPflanzengenetik undKulturpflanzenforschung (IPK)GeneBank. Major resistance genes Rlm1, Rlm2, Rlm4 and theputative RlmBBA gene wereinvestigated using genetically improvedstrains of the fungus harbouring as fewcorresponding avirulence genes as possible.In addition, a screening with fullyvirulent isolates was used to uncover novelresistance sources. Major resistance geneswere rarer in frequency and diversity inspring-type cultivars compared to wintertypes. In the former, 65.7% of theaccessions were fully susceptible to allisolates, whereas only 12.2% of the wintertypes were devoid of at least one R gene.In spring cultivars, the most common Rgene, Rlm4 was found in 26.6% ofaccessions, whereas the other R genes wererare. In winter cultivars, the most commonR genes were Rlm2 (more than45.9–54.0% of the accessions) and Rlm4 (26.4–27.7% of the genotypes). Inwinter types however, the improvement ofthe quality of oils, through the generationof single- and double-low genotypesimproved the homogeneity of the cvs,whereas it impoverished R gene diversity,including the loss of complete resistancethat was harboured by 18.4% of the lessadvanced accessions, and a reduction in theratio of accessions harbouring Rlm1.Correlation between the R gene(s) presentin the accessions and their fieldresistance is discussed.