School of Agriculture and Food Sciences, University of Queensland, Brisbane, QLD, Australia.
School of Biological Sciences, University of Western Australia, Perth, WA, Australia.
Theor Appl Genet. 2021 Jul;134(7):2035-2050. doi: 10.1007/s00122-021-03803-4. Epub 2021 Mar 25.
One hundred and sixty-seven B. juncea varieties were genotyped on the 90K Brassica assay (42,914 SNPs), which led to the identification of sixteen candidate genes for Rlm6. Brassica species are at high risk of severe crop loss due to pathogens, especially Leptosphaeria maculans (the causal agent of blackleg). Brassica juncea (L.) Czern is an important germplasm resource for canola improvement, due to its good agronomic traits, such as heat and drought tolerance and high blackleg resistance. The present study is the first using genome-wide association studies to identify candidate genes for blackleg resistance in B. juncea based on genome-wide SNPs obtained from the Illumina Infinium 90 K Brassica SNP array. The verification of Rlm6 in B. juncea was performed through a cotyledon infection test. Genotyping 42,914 single nucleotide polymorphisms (SNPs) in a panel of 167 B. juncea lines revealed a total of seven SNPs significantly associated with Rlm6 on chromosomes A07 and B04 in B. juncea. Furthermore, 16 candidate Rlm6 genes were found in these regions, defined as nucleotide binding site leucine-rich-repeat (NLR), leucine-rich repeat RLK (LRR-RLK) and LRR-RLP genes. This study will give insights into the blackleg resistance in B. juncea and facilitate identification of functional blackleg resistance genes which can be used in Brassica breeding.
167 份芥菜品种进行了 90K 芸薹属基因分型分析（42914 个 SNP），从中鉴定出 16 个与 Rlm6 相关的候选基因。芸薹属植物由于病原体的存在而面临严重减产的高风险，尤其是黑胫病菌（导致黑胫病的病原体）。芥菜（L.）Czern 是油菜改良的重要种质资源，因为它具有良好的农艺性状，如耐热和耐旱性以及高黑胫病抗性。本研究首次利用全基因组关联研究，基于 Illumina Infinium 90K 芸薹属 SNP 阵列获得的全基因组 SNP，鉴定芥菜中黑胫病抗性的候选基因。通过子叶感染试验验证了 Rlm6 在芥菜中的存在。在 167 份芥菜品系的panel 中对 42914 个单核苷酸多态性（SNP）进行基因分型，结果在芥菜的 A07 和 B04 染色体上共发现了 7 个与 Rlm6 显著相关的 SNP。此外，在这些区域还发现了 16 个候选 Rlm6 基因，它们被定义为核苷酸结合位点富含亮氨酸重复（NLR）、富含亮氨酸重复的受体样激酶（LRR-RLK）和富含亮氨酸重复的 RLK（LRR-RLK）和 LRR-RLP 基因。本研究将深入了解芥菜的黑胫病抗性，并有助于鉴定可用于芸薹属作物育种的功能黑胫病抗性基因。
