PDF(Pubmed)
Abstract：
Clubroot disease poses a significant threat to Brassica crops, necessitating ongoing updates on resistance gene sources. In F2 segregants of the clubroot-resistant inbred line BrT18-6-4-3 and susceptible DH line Y510, the genetic analysis identified a single dominant gene responsible for clubroot resistance. Through bulk segregant sequencing analysis and kompetitive allele-specific polymerase chain reaction assays, CRA8.1.6 was mapped within 110 kb (12,255-12,365 Mb) between markers L-CR11 and L-CR12 on chromosome A08. We identified B raA08g015220.3.5C as the candidate gene of CRA8.1.6. Upon comparison with the sequence of disease-resistant material BrT18-6-4-3, we found 249 single-nucleotide polymorphisms, seven insertions, six deletions, and a long terminal repeat (LTR) retrotransposon (5,310 bp) at 909 bp of the first intron. However, the LTR retrotransposon was absent in the coding sequence of the susceptible DH line Y510. Given the presence of a non-functional LTR insertion in other materials, it showed that the LTR insertion might not be associated with susceptibility. Sequence alignment analysis revealed that the fourth exon of the susceptible line harbored two deletions and an insertion, resulting in a frameshift mutation at 8,551 bp, leading to translation termination at the leucine-rich repeat domain\'s C-terminal in susceptible material. Sequence alignment of the CDS revealed a 99.4% similarity to Crr1a, which indicate that CRA8.1.6 is likely an allele of the Crr1a gene. Two functional markers, CRA08-InDel and CRA08-KASP1, have been developed for marker-assisted selection in CR turnip cultivars. Our findings could facilitate the development of clubroot-resistance turnip cultivars through marker-assisted selection.
摘要：
丛枝病对芸苔属作物构成重大威胁,需要持续更新抗性基因来源。在抗根瘤菌自交系BrT18-6-4-3和易感DH系Y510的F2分离物中，遗传分析确定了一个负责根瘤菌抗性的显性基因。通过批量分离测序分析和竞争性等位基因特异性聚合酶链反应测定，CRA8.1.6在染色体A08上的标记L-CR11和L-CR12之间的110kb（12,255-12,365Mb）内定位。我们确定BraA08g015220.3.5C为CRA8.1.6的候选基因。通过与抗病材料BrT18-6-4-3的序列比较，我们发现249个单核苷酸多态性，七个插入，六个删除，和第一个内含子909bp处的长末端重复序列（LTR）反转录转座子（5,310bp）。然而,易感DH系Y510的编码序列中不存在LTR反转录转座子。鉴于在其他材料中存在非功能性LTR插入，这表明LTR插入可能与易感性无关.序列比对分析表明，易感系的第四个外显子包含两个缺失和一个插入，导致8,551bp的移码突变，导致易感材料中富含亮氨酸的重复结构域C末端的翻译终止。CDS的序列比对显示与Crr1a有99.4%的相似性，这表明CRA8.1.6可能是Crr1a基因的等位基因。两个功能标记，CRA08-InDel和CRA08-KASP1已开发用于CR萝卜品种的标记辅助选择。我们的发现可以通过标记辅助选择促进抗根茎萝卜品种的发展。
