State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China.
BMC Plant Biol. 2024 Oct 20;24(1):987. doi: 10.1186/s12870-024-05685-2.
Cabbage (Brassica oleracea L. var. capitata) is an important crop within the Brassica oleracea species and is extensively cultivated worldwide. In recent years, outbreaks of downy mildew caused by Hyaloperonospora parasitica have resulted in substantial losses in cabbage production. Despite this, there have been limited studies on genes associated with resistance to downy mildew in cabbage.
This study identified sister lines exhibiting significant differences in disease resistance and susceptibility. Using bulked segregant analysis followed by sequencing (BSA-seq) and linkage analysis, the cabbage resistance locus BoDMR2 was accurately mapped to an approximately 300 kb interval on chromosome 7. Among the candidate genes identified, several single nucleotide polymorphisms (SNPs) and a 3-bp insertion were found within the conserved domain of the Bo7g117810 gene, encoding a leucine-rich repeat domain protein, in susceptible genotypes. Additionally, real-time quantitative polymerase chain reaction (RT‒qPCR) analysis revealed that the expression level of Bo7g117810 in resistant specimens was 2.5-fold higher than that in susceptible specimens. An insertion‒deletion (InDel) marker was designed based on the identified insertion in susceptible materials, facilitating the identification and selection of downy mildew-resistant cabbage cultivars.
This study identifies Bo7g117810 as a potential candidate gene associated with adult-stage resistance to downy mildew in cabbage, supported by observed differences in gene sequence and expression levels. Furthermore, the development of an InDel marker I1-3, based on its mutation, provides valuable resources for breeding resistant cabbage cultivars.
结球甘蓝（Brassica oleracea L. var. capitata）是芸薹属作物中的重要一员，在全球范围内广泛种植。近年来，由寄生霜霉引起的霜霉病爆发导致结球甘蓝产量大幅下降。尽管如此，关于结球甘蓝抗霜霉病相关基因的研究却十分有限。
本研究鉴定了在抗病性和感病性方面表现出显著差异的姊妹系。通过 bulked segregant analysis followed by sequencing（BSA-seq）和连锁分析，将结球甘蓝抗性基因 BoDMR2 准确定位到 7 号染色体上约 300kb 的区间内。在所鉴定的候选基因中，在感病基因型中发现了 Bo7g117810 基因的保守结构域内存在几个单核苷酸多态性（SNP）和 3 个碱基插入，该基因编码富含亮氨酸重复结构域的蛋白质。此外，实时定量聚合酶链反应（RT‒qPCR）分析显示，抗性样本中 Bo7g117810 的表达水平是感病样本的 2.5 倍。根据易感材料中鉴定的插入，设计了插入缺失（InDel）标记，为鉴定和选择抗霜霉病结球甘蓝品种提供了便利。
本研究发现 Bo7g117810 是一个与结球甘蓝成株期抗霜霉病相关的潜在候选基因，这一结论得到了基因序列和表达水平差异的支持。此外，基于其突变开发的 InDel 标记 I1-3 为培育抗霜霉病结球甘蓝品种提供了有价值的资源。
