Department of Plant Pathology, University of California, Davis, CA, 95616, USA.
Present address: Indigo Ag, Charlestown, MA, 02129, USA.
BMC Plant Biol. 2019 Jul 10;19(1):305. doi: 10.1186/s12870-019-1905-9.
Verticillium wilt caused by the fungus Verticillium dahliae race 1 is among the top disease concerns for lettuce in the Salinas and Pajaro Valleys of coastal central California. Resistance of lettuce against V. dahliae race 1 was previously mapped to the single dominant Verticillium resistance 1 (Vr1) locus. Lines of tomato resistant to race 1 are known to contain the closely linked Ve1 and Ve2 genes that encode receptor-like proteins with extracellular leucine-rich repeats; the Ve1 and Ve2 proteins act antagonistically to provide resistance against V. dahliae race 1. The Vr1 locus in lettuce contains a cluster of several genes with sequence similarity to the tomato Ve genes. We used genome sequencing and/or PCR screening along with pathogenicity assays of 152 accessions of lettuce to investigate allelic diversity and its relationship to race 1 resistance in lettuce.
This approach identified a total of four Ve genes: LsVe1, LsVe2, LsVe3, and LsVe4. The majority of accessions, however, contained a combination of only three of these LsVe genes clustered on chromosomal linkage group 9 (within ~ 25 kb in the resistant cultivar La Brillante and within ~ 127 kb in the susceptible cultivar Salinas).
A single allele, LsVe1L, was present in all resistant accessions and absent in all susceptible accessions. This allele can be used as a molecular marker for V. dahliae race 1 resistance in lettuce. A PCR assay for rapid detection of race 1 resistance in lettuce was designed based on nucleotide polymorphisms. Application of this assay allows identification of resistant genotypes in early stages of plant development or at seed-level without time- and labor-intensive testing in the field.
由真菌黄萎轮枝菌 1 型引起的黄萎病是加利福尼亚州海岸萨利纳斯和帕哈罗山谷生菜的首要疾病关注点之一。生菜对黄萎轮枝菌 1 型的抗性以前被定位到单个显性黄萎病抗性 1（Vr1）基因座上。已知具有抗 1 型的番茄品系含有紧密连锁的 Ve1 和 Ve2 基因，这些基因编码具有细胞外亮氨酸丰富重复的受体样蛋白；Ve1 和 Ve2 蛋白拮抗作用，为抵抗黄萎轮枝菌 1 型提供抗性。生菜中的 Vr1 基因座包含几个与番茄 Ve 基因具有序列相似性的基因簇。我们使用基因组测序和/或 PCR 筛选以及对 152 份生菜材料的致病性测定，研究了等位基因多样性及其与生菜 1 型抗性的关系。
这种方法总共鉴定出了 4 个 Ve 基因：LsVe1、LsVe2、LsVe3 和 LsVe4。然而，大多数品系仅包含这 3 个 LsVe 基因的组合，这些基因簇位于染色体连锁群 9 上（在抗性品种 La Brillante 中约 25 kb 内，在易感品种 Salinas 中约 127 kb 内）。
所有抗性品系都存在一个单等位基因 LsVe1L，而所有易感品系都不存在。该等位基因可作为生菜抗黄萎轮枝菌 1 型的分子标记。基于核苷酸多态性，设计了一种用于快速检测生菜 1 型抗性的 PCR 检测方法。该检测方法的应用可以在植物发育的早期阶段或在种子水平上鉴定抗性基因型，而无需在田间进行耗时和劳动密集型测试。
