Molecular mapping of Stb1, a potentially durable gene for resistance to septoria tritici blotch in wheat
Molecular mapping of Stb1, a potentially durable gene for resistance to septoria tritici blotch in wheat
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DOI：
10.1007/s00122-004-1709-6
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发表时间：
2004-09-01
影响因子：
5.4
通讯作者：
Goodwin, SB
中科院分区：
文献类型：
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作者：
Adhikari, TB;Yang, X;Goodwin, SB
小麦黑斑病(SepVictoria tritici blotch，STB)是由子囊菌Mycosphaerella graminicola(无性型)引起的小麦黑斑病，在20世纪70年代初抗性基因Stb1问世之前，曾是印第安纳州及邻近各州危害最严重的小麦病害。从那时起，Stb1在广泛种植的小麦品种中提供了对STB的持久保护。然而，它的染色体位置和与大多数其他STB基因的等位基因关系尚不清楚，因此Stb1的分子定位非常有意义。对两个作图群体进行了遗传分析和分子定位。用抗病品系P881072-75-1与感病品系P881072-75-2与孟农进行三交，共获得148个F-1植株(作图群体I)，从抗病品系72626E_2-12-9-1与感病品种Arthur杂交获得106个F-6重组自交系(作图群体II)。利用随机扩增多态性DNA(RAPD)、扩增片段长度多态性(AFLP)和微卫星或简单序列重复(SSR)标记进行批量分离分析，以鉴定与Stb1基因可能连锁的基因。分离分析证实，在每个定位群体中，一个显性基因控制着对稻瘟病菌的抗性。G7(1200)和H19(520)标记分别与小麦品系P881072-75-1的Stb1紧密连锁，连锁距离分别小于0.68 cM和1.4 cM。在作图群体II中，连锁最紧密的标记是SSR Xbarc74，位于5BL上Stb1近端2.8 cM处。微卫星座位Xgwm335和Xgwm213也分别位于距Stb1近7.4 cM和8.3 cM的位置。AFLP侧翼标记EcoRI-AGC/MseI-CTA-1位于Stb1远端8.4 cM处。将G71200和H19520两个随机扩增标记和AFLP ecoRI-AGC/MseI-CTA-1进行克隆和测序，转化为序列特征扩增区(SCAR)标记。只有等位基因H19(520)能被成功转化，所有的SCAR标记都不能对Stb1位点进行诊断。SSR和原5BL缺失群体的随机扩增结果表明，Stb1基因座位于染色体断裂点区域，片段长度分别为0.59和0.75。与Stb1紧密连锁的分子标记可用于辅助选择和将Stb1与其他抗稻瘟病菌基因聚合。
Septoria tritici blotch (STB), caused by the ascomycete Mycosphaerella graminicola (anamorph Septoria tritici), was the most destructive disease of wheat in Indiana and adjacent states before deployment of the resistance gene Stb1 during the early 1970s. Since then, Stb1 has provided durable protection against STB in widely grown wheat cultivars. However, its chromosomal location and allelic relationships to most other STB genes are not known, so the molecular mapping of Stb1 is of great interest. Genetic analyses and molecular mapping were performed for two mapping populations. A total of 148 F-1 plants (mapping population I) were derived from a three-way cross between the resistant line P881072-75-1 and the susceptible lines P881072-75-2 and Monon, and 106 F-6 recombinant-inbred lines (mapping population II) were developed from a cross between the resistant line 72626E2-12-9-1 and the susceptible cultivar Arthur. Bulked-segregant analysis with random amplified polymorphic DNA (RAPD), amplified fragment length polymorphism (AFLP), and microsatellite or simple-sequence repeat (SSR) markers was conducted to identify those that were putatively linked to the Stb1 gene. Segregation analyses confirmed that a single dominant gene controls the resistance to M. graminicola in each mapping population. Two RAPD markers, G7(1200) and H19(520), were tightly linked to Stb1 in wheat line P881072-75-1 at distances of less than 0.68 cM and 1.4 cM, respectively. In mapping population II, the most closely linked marker was SSR Xbarc74, which was 2.8 cM proximal to Stb1 on chromosome 5BL. Microsatellite loci Xgwm335 and Xgwm213 also were proximal to Stb1 at distances of 7.4 cM and 8.3 cM, respectively. The flanking AFLP marker, EcoRI-AGC/MseI-CTA-1, was 8.4 cM distal to Stb1. The two RAPD markers, G71200 and H19520, and AFLP ECORI-AGC/MseI-CTA-1, were cloned and sequenced for conversion into sequence-characterized amplified region (SCAR) markers. Only RAPD allele H19(520) could be converted successfully, and none of the SCAR markers was diagnostic for the Stb1 locus. Analysis of SSR and the original RAPD primers on several 5BL deletion stocks positioned the Stb1 locus in the region delineated by chromosome breakpoints at fraction lengths 0.59 and 0.75. The molecular markers tightly linked to Stb1 could be useful for marker-assisted selection and for pyramiding of Stb1 with other genes for resistance to M. graminicola in wheat.