Ameline-Torregrosa Carine, Cazaux Marc, Danesh Dariush, Chardon Fabien, Cannon Steven B, Esquerré-Tugayé Marie-Thérèse, Dumas Bernard, Young Nevin D, Samac Deborah A, Huguet Thierry, Jacquet Christophe
UMR 5546, Centre National de la Recherche Scientifique-UPS, Pôle de Biotechnologie Végétale, 24 Chemin Borde Rouge, 34326 Castanet-Tolosan, France.
Mol Plant Microbe Interact. 2008 Jan;21(1):61-9. doi: 10.1094/MPMI-21-1-0061.
Medicago truncatula was used to characterize resistance to anthracnose and powdery mildew caused by Colletotrichum trifolii and Erysiphe pisi, respectively. Two isolates of E. pisi (Ep-p from pea and Ep-a from alfalfa) and two races of C. trifolii (races 1 and 2) were used in this study. The A17 genotype was resistant and displayed a hypersensitive response after inoculation with either pathogen, while lines F83005.5 and DZA315.16 were susceptible to anthracnose and powdery mildew, respectively. To identify the genetic determinants underlying resistance in A17, two F7 recombinant inbred line (RIL) populations, LR4 (A17 x DZA315.16) and LR5 (A17 x F83005.5), were phenotyped with E. pisi isolates and C. trifolii races, respectively. Genetic analyses showed that i) resistance to anthracnose is governed mainly by a single major locus to both races, named Ct1 and located on the upper part of chromosome 4; and ii) resistance to powdery mildew involves three distinct loci, Epp1 on chromosome 4 and Epa1 and Epa2 on chromosome 5. The use of a consensus genetic map for the two RIL populations revealed that Ct1 and Epp1, although located in the same genome region, were clearly distinct. In silico analysis in this region identified the presence of several clusters of nucleotide binding site leucine-rich repeat genes. Many of these genes have atypical resistance gene analog structures and display differential expression patterns in distinct stress-related cDNA libraries.
蒺藜苜蓿被用于分别鉴定对由三叶草炭疽菌和豌豆白粉菌引起的炭疽病和白粉病的抗性。本研究使用了两种豌豆白粉菌分离株（来自豌豆的Ep-p和来自苜蓿的Ep-a）以及三叶草炭疽菌的两个小种（小种1和小种2）。A17基因型具有抗性，接种任何一种病原菌后均表现出过敏反应，而F83005.5和DZA315.16品系分别对白粉病和炭疽病敏感。为了鉴定A17中抗性的遗传决定因素，分别用豌豆白粉菌分离株和三叶草炭疽菌小种对两个F7重组自交系（RIL）群体LR4（A17×DZA315.16）和LR5（A17×F83005.5）进行了表型分析。遗传分析表明：i）对炭疽病的抗性主要由一个单一位点控制，该位点对两个小种均起作用，命名为Ct1，位于4号染色体的上部；ii）对白粉病的抗性涉及三个不同的位点，4号染色体上的Epp1以及5号染色体上的Epa1和Epa2。对两个RIL群体使用共有的遗传图谱表明，尽管Ct1和Epp1位于同一基因组区域，但它们明显不同。该区域的电子分析确定存在几个核苷酸结合位点富含亮氨酸重复序列基因簇。这些基因中的许多具有非典型的抗性基因类似物结构，并在不同的胁迫相关cDNA文库中表现出差异表达模式。
