Institute of Crop Sciences, National Wheat Improvement Center, Chinese Academy of Agricultural Sciences (CAAS), 12 Zhongguancun South Street, Beijing, 100081, China.
Department of Plant Genetics & Breeding/State Key Laboratory for Agrobiotechnology, China Agricultural University, 2 Yuanmingyuan West Road, Beijing, 100193, China.
BMC Plant Biol. 2017 Nov 23;17(1):220. doi: 10.1186/s12870-017-1167-3.
Black point is a serious threat to wheat production and can be managed by host resistance. Marker-assisted selection (MAS) has the potential to accelerate genetic improvement of black point resistance in wheat breeding. We performed a genome-wide association study (GWAS) using the high-density wheat 90 K and 660 K single nucleotide polymorphism (SNP) assays to better understand the genetic basis of black point resistance and identify associated molecular markers.
Black point reactions were evaluated in 166 elite wheat cultivars in five environments. Twenty-five unique loci were identified on chromosomes 2A, 2B, 3A, 3B (2), 3D, 4B (2), 5A (3), 5B (3), 6A, 6B, 6D, 7A (5), 7B and 7D (2), respectively, explaining phenotypic variation ranging from 7.9 to 18.0%. The highest number of loci was detected in the A genome (11), followed by the B (10) and D (4) genomes. Among these, 13 were identified in two or more environments. Seven loci coincided with known genes or quantitative trait locus (QTL), whereas the other 18 were potentially novel loci. Linear regression showed a clear dependence of black point scores on the number of favorable alleles, suggesting that QTL pyramiding will be an effective approach to increase resistance. In silico analysis of sequences of resistance-associated SNPs identified 6 genes possibly involved in oxidase, signal transduction and stress resistance as candidate genes involved in black point reaction.
SNP markers significantly associated with black point resistance and accessions with a larger number of resistance alleles can be used to further enhance black point resistance in breeding. This study provides new insights into the genetic architecture of black point reaction.
黑斑病是小麦生产的严重威胁，可以通过寄主抗性来控制。标记辅助选择（MAS）有可能加速小麦抗黑斑病的遗传改良。我们利用高密度小麦 90K 和 660K 单核苷酸多态性（SNP）检测进行了全基因组关联研究（GWAS），以更好地了解黑斑病抗性的遗传基础，并鉴定相关的分子标记。
在五个环境中对 166 个小麦优良品种的黑斑病反应进行了评估。在染色体 2A、2B、3A、3B（2）、3D、4B（2）、5A（3）、5B（3）、6A、6B、6D、7A（5）、7B 和 7D（2）上分别鉴定出 25 个独特的位点，解释了表型变异范围从 7.9%到 18.0%。在 A 基因组中检测到的位点数量最多（11 个），其次是 B（10 个）和 D（4 个）基因组。其中，有 13 个在两个或更多环境中被鉴定出来。7 个位点与已知基因或数量性状位点（QTL）重合，而其他 18 个可能是新的位点。线性回归显示黑斑病评分与有利等位基因的数量明显相关，表明 QTL 聚合将是提高抗性的有效方法。与抗性相关的 SNP 序列的计算机分析鉴定了 6 个可能参与氧化酶、信号转导和应激反应的基因，作为参与黑斑病反应的候选基因。
与黑斑病抗性显著相关的 SNP 标记和具有更多抗性等位基因的品种可用于进一步提高育种中的黑斑病抗性。本研究为黑斑病反应的遗传结构提供了新的见解。
