Agriculture and Agri-Food Canada, Saskatoon Research and Development Centre, 107 Science Place, Saskatoon, SK, S7N OX2, Canada.
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada.
Sci Rep. 2017 Jul 3;7(1):4516. doi: 10.1038/s41598-017-04903-2.
Clubroot, caused by Plasmodiophora brassicae, is an important disease of Brassica crops worldwide. F progeny from the Brassica rapa lines T19 (resistant) × ACDC (susceptible) were backcrossed with ACDC, then self-pollinated to produce BCS lines, From genotyping-by-sequencing (GBS) of the parental lines and BC plants, about 1.32 M sequences from T19 were aligned into the reference genome of B. rapa with 0.4-fold coverage, and 1.77 M sequences with 0.5-fold coverage in ACDC. The number of aligned short reads per plant in the BC ranged from 0.07 to 1.41 M sequences with 0.1-fold coverage. A total of 1584 high quality SNP loci were obtained, distributed on 10 chromosomes. A single co-localized QTL, designated as Rcr4 on chromosome A03, conferred resistance to pathotypes 2, 3, 5, 6 and 8. The peak was at SNP locus A03_23710236, where LOD values were 30.3 to 38.8, with phenotypic variation explained (PVE) of 85-95%. Two QTLs for resistance to a novel P. brassicae pathotype 5x, designated Rcr8 on chromosome A02 and Rcr9 on A08, were detected with 15.0 LOD and 15.8 LOD, and PVE of 36% and 39%, respectively. Bulked segregant analysis was performed to examine TIR-NBS-LRR proteins in the regions harboring the QTL.
根肿病由芸薹根肿菌引起，是世界范围内十字花科作物的重要病害。用甘蓝型油菜品种 T19（抗性）×ACDC（感病）的 F1 代回交 ACDC，然后自交产生 BCS 系。通过对亲本和 BC 植株的基因型测序（GBS），T19 的约 1.32M 序列以 0.4 倍覆盖度比对到芸薹属白菜的参考基因组中，ACDC 中有 1.77M 序列以 0.5 倍覆盖度比对。BC 中每株的比对短读长在 0.07 到 1.41M 序列之间，以 0.1 倍覆盖度比对。共获得 1584 个高质量 SNP 位点，分布在 10 条染色体上。单个共定位 QTL 被命名为 A03 染色体上的 Rcr4，对致病型 2、3、5、6 和 8 表现抗性。该 QTL 峰值位于 SNP 位点 A03_23710236，LOD 值为 30.3 到 38.8，表型变异解释率（PVE）为 85-95%。在 A02 染色体上检测到了一个对新型芸薹根肿菌致病型 5x 的抗性 QTL，命名为 Rcr8，在 A08 染色体上检测到了另一个抗性 QTL，命名为 Rcr9，LOD 值分别为 15.0 和 15.8，PVE 分别为 36%和 39%。利用 TIR-NBS-LRR 蛋白进行了区间 Bulked segregant analysis。
