School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, UK.
G3 (Bethesda). 2020 May 4;10(5):1753-1763. doi: 10.1534/g3.120.401119.
The molecular interactions between tomato and have been an important model for molecular plant pathology. Complex genetic loci on tomato chromosomes 1 and 6 harbor genes for resistance to , encoding receptor like-proteins that perceive distinct effectors and trigger plant defenses. Here, we report classical mapping strategies for loci in tomato accessions that respond to effector Ecp5, which is very sequence-monomorphic. We screened 139 wild tomato accessions for an Ecp5-induced hypersensitive response, and in five accessions, the Ecp5-induced hypersensitive response segregated as a monogenic trait, mapping to distinct loci in the tomato genome. We identified at least three loci on chromosomes 1, 7 and 12 that harbor distinct genes in four different accessions. Our mapping showed that the in G1.1161 is located at the locus. The in LA0722 was mapped to the bottom arm of chromosome 7, while the genes in Ontario 7522 and LA2852 were mapped to the same locus on the top arm of chromosome 12. Bi-parental crosses between accessions carrying distinct Cf-Ecp5 genes revealed putative genetically unlinked suppressors of the Ecp5-induced hypersensitive response. Our mapping also showed that is located on chromosome 11, close to the locus. The Ecp5-induced hypersensitive response is widely distributed within tomato species and is variable in strength. This novel example of convergent evolution could be used for choosing different functional genes according to individual plant breeding needs.
番茄与叶霉菌互作是植物分子病理学的重要模式。番茄染色体 1 和 6 上的复杂遗传位点含有抗叶霉菌的基因，这些基因编码识别不同效应子并触发植物防御的类受体蛋白。在这里，我们报告了针对番茄品系中响应叶霉菌效应子 Ecp5 的基因座的经典作图策略，Ecp5 非常序列单一。我们筛选了 139 个野生番茄品系对 Ecp5 诱导的过敏反应，在五个品系中，Ecp5 诱导的过敏反应作为单基因性状分离，映射到番茄基因组中的不同基因座。我们在四个不同的品系中鉴定了至少三个位于染色体 1、7 和 12 上的不同基因座，这些基因座含有不同的基因。我们的作图表明，G1.1161 中的基因位于位点。LA0722 中的基因位于染色体 7 的底部臂，而 Ontario 7522 和 LA2852 中的基因位于染色体 12 的顶部臂的相同基因座上。携带不同 Cf-Ecp5 基因的品系之间的双亲杂交揭示了 Ecp5 诱导的过敏反应的潜在遗传不连锁抑制子。我们的作图还表明，基因位于染色体 11 上，靠近位点。Ecp5 诱导的过敏反应在番茄种内广泛分布，其强度具有可变性。这种新的趋同进化的例子可以根据个体植物育种的需要来选择不同的功能基因。
