Phytopathology. 2004 Nov;94(11):1198-206. doi: 10.1094/PHYTO.2004.94.11.1198.
ABSTRACT Breeding wheat for resistance is the most effective means to control Septoria tritici blotch (STB), caused by the ascomycete Mycosphaerella graminicola (anamorph Septoria tritici). At least eight genes that confer resistance to STB in wheat have been identified. Among them, the Stb4 locus from the wheat cv. Tadinia showed resistance to M. graminicola at both seedling and adult-plant stages. However, no attempt has been made to map the Stb4 locus in the wheat genome. A mapping population of 77 F10 recombinant-inbred lines (RILs) derived from a three-way cross between the resistant cv. Tadinia and the susceptible parent (Yecora Rojo x UC554) was evaluated for disease resistance and molecular mapping. The RILs were tested with Argentina isolate I 89 of M. graminicola for one greenhouse season in Brazil during 1999, with an isolate from Brazil (IPBr1) for one field season in Piracicaba (Brazil) during 2000, and with Indiana tester isolate IN95-Lafayette-1196-WW-1-4 in the greenhouse during 2000 and 2001. The ratio of resistant:susceptible RILs was 1:1 in all three tests, confirming the single-gene model for control of resistance to STB in Tadinia. However, the patterns of resistance and susceptibility were different between the Indiana isolate and those from South America. For example, the ratio of RILs resistant to both the Indiana and Argentina isolates, resistant to one but susceptible to the other, and susceptible to both isolates was approximately 1:1:1:1, indicating that Tadinia may contain at least two genes for resistance to STB. A similar pattern was observed between the Indiana and Brazil isolates. The gene identified with the Indiana tester isolate was assumed to be the same as Stb4, whereas that revealed by the South American isolates may be new. Bulked-segregant analysis was used to identify amplified fragment length polymorphism (AFLP) and microsatellite markers linked to the presumed Stb4 gene. The AFLP marker EcoRI-ACTG/MseI-CAAA5 and microsatellite Xgwm111 were closely linked to the Stb4 locus in coupling at distances of 2.1 and 0.7 centimorgans (cM), respectively. A flanking marker, AFLP EAGG/ M-CAT10, was 4 cM from Stb4. The Stb4 gene was in a potential supercluster of resistance genes near the centromere on the short arm of wheat chromosome 7D that also contained Stb5 plus five previously identified genes for resistance to Russian wheat aphid. The microsatellite marker Xgwm111 identified in this study may be useful for facilitating the transfer of Stb4 into improved cultivars of wheat.
摘要 培育小麦抗性是控制叶锈病（STB）的最有效手段，叶锈病是由子囊菌麦喙点霉（无性型为叶锈菌）引起的。目前已经鉴定出至少 8 个赋予小麦 STB 抗性的基因。其中，来自小麦品种 Tadinia 的 Stb4 基因座在幼苗和成株期均表现出对 M. graminicola 的抗性。然而，尚未尝试在小麦基因组中对 Stb4 基因座进行定位。利用来自抗叶锈病品种 Tadinia 和感病亲本（Yecora Rojo x UC554）的三交衍生的 77 个 F10 重组自交系（RIL）群体，在 1999 年巴西的一个温室季节、2000 年巴西皮拉西卡巴（Piracicaba）的一个田间季节以及 2000 年和 2001 年在温室中的印第安纳测试者分离株 IN95-Lafayette-1196-WW-1-4 对其进行了抗病性和分子作图评估。在所有三种测试中，抗性：感病 RIL 的比例均为 1:1，这证实了 Tadinia 中 STB 抗性的单基因模型。然而，印第安纳分离株与来自南美的分离株的抗性和感性模式不同。例如，对印第安纳和阿根廷分离株均抗性、对其中一个分离株抗性而对另一个分离株感性、对两个分离株均感性的 RIL 比例约为 1:1:1:1，表明 Tadinia 可能含有至少两个 STB 抗性基因。在印第安纳和巴西分离株之间观察到类似的模式。与印第安纳测试者分离株鉴定的基因假定为 Stb4，而与南美分离株鉴定的基因可能是新的。使用分组分离分析鉴定与假定的 Stb4 基因连锁的扩增片段长度多态性（AFLP）和微卫星标记。AFLP 标记 EcoRI-ACTG/MseI-CAAA5 和微卫星 Xgwm111 与 Stb4 基因座在连锁距离为 2.1 和 0.7 厘摩（cM）处紧密连锁。侧翼标记 AFLP EAGG/M-CAT10 与 Stb4 相距 4 cM。Stb4 基因位于小麦 7D 染色体短臂着丝粒附近的抗性基因超基因簇中，该基因簇还包含 Stb5 以及先前鉴定的 5 个抗俄罗斯麦蚜的基因。本研究中鉴定的微卫星标记 Xgwm111 可能有助于将 Stb4 转移到小麦改良品种中。
