Department of Vegetable Science, China Agricultural University, Beijing, China.
Phytopathology. 2011 Oct;101(10):1217-23. doi: 10.1094/PHYTO-12-10-0345.
Bacterial spot of tomato (Solanum lycopersicum) is caused by four species of Xanthomonas. The disease causes significant yield losses and a reduction in fruit quality. Physiological races have been described with tomato race 3 (T3) corresponding to strains of Xanthomonas perforans. The breeding line Hawaii 7981 (hereafter H7981) shows a hypersensitive reaction (HR) to race T3 strains conditioned by the interaction of the host resistance locus Xv3 and the bacterial effector avrXv3. The Xv3 gene is required for H7981-derived resistance to be effective under field conditions, though its expression is subject to genetic background. The segregation of HR in F(2) populations derived from H7981 crossed to processing tomato parents OH88119 and OH7870 was studied in 331 progeny, with the two independent crosses providing validation. We screened 453 simple-sequence repeat, insertion/deletion, and single-nucleotide polymorphism markers and identified 44 polymorphic markers each for the OH88119 and OH7870 populations covering 84.6 and 73.3% of the genome, respectively, within 20 centimorgans (cM). Marker-trait analysis using all polymorphic markers demonstrated that Xv3-mediated resistance maps to chromosome 11 in the two independent crosses. Allelism tests were conducted in crosses between lines carrying Xv3 derived from H7981, Rx-4 derived from plant introduction (PI) 128216, and resistance derived from PI 126932. These allelism tests suggested that the loci conditioning HR to race T3 strains are linked within 0.1 cM, are allelic, or are the same gene.
番茄细菌性斑点病（Solanum lycopersicum）由四种黄单胞菌引起。这种疾病会导致显著的产量损失和果实品质下降。已经描述了生理小种，番茄小种 3（T3）对应于黄单胞菌穿孔变种的菌株。品系 Hawaii 7981（简称 H7981）对 T3 小种菌株表现出过敏反应（HR），这种 HR 是由宿主抗性基因 Xv3 与细菌效应因子 avrXv3 的相互作用所决定的。Xv3 基因是 H7981 衍生抗性在田间条件下有效的必要条件，尽管其表达受遗传背景的影响。在 H7981 与加工番茄亲本 OH88119 和 OH7870 杂交产生的 F2 群体中，HR 的分离情况在 331 个后代中进行了研究，两个独立的杂交提供了验证。我们筛选了 453 个简单序列重复、插入/缺失和单核苷酸多态性标记，分别为 OH88119 和 OH7870 群体鉴定了 44 个多态性标记，分别覆盖了基因组的 84.6%和 73.3%，每个标记的间距为 20 厘摩。利用所有多态性标记进行的标记-性状分析表明，Xv3 介导的抗性在两个独立的杂交中都位于第 11 号染色体上。在携带 H7981 衍生的 Xv3、植物引种（PI）128216 衍生的 Rx-4 和 PI 126932 衍生的抗性的品系之间进行了等位基因测试。这些等位基因测试表明，决定 T3 小种菌株 HR 的基因座在 0.1 厘摩内连锁，是等位基因，或者是同一个基因。
