Inst. of Plant Breeding, Genetics, and Genomics, Univ. of Georgia, Griffin Campus, Griffin, GA, 30223.
Inst. of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
Plant Genome. 2019 Nov;12(3):1-14. doi: 10.3835/plantgenome2019.05.0033.
The emergence of new virulent Puccinia triticina races requires a continuous search for novel sources of resistance to combat leaf rust (LR) disease Twenty-two wheat genotypes resistant to four P. triticina races were identified in this study A genome-wide association study detected 11 quantitative trait loci for LR resistance; five of them were detected on genomic regions where no LR resistant genes have been detected. Wheat (Triticum aestivum L.) production worldwide is being challenged by several biotic and abiotic factors. Leaf rust (LR), caused by Puccinia triticina, is a major biotic constraint of wheat production worldwide. Genetic resistance is the most efficient and cost-effective way to control LR. Seventy-nine LR resistance genes have been identified to date but the frequent emergence of new virulent P. triticina races every year demands a constant search for new sources of resistance with novel quantitative trait loci (QTL) or genes. The objectives of this study were to identify putative novel sources of effective resistance against the current prevalent races of P. triticina in the southeast United States and to map genomic loci associated with LR resistance via a genome-wide association study (GWAS) approach. Evaluation of 331 diverse wheat genotypes against four prevalent P. triticina races (MFGKG, MBTNB, MCTNB, and TCRKG) revealed that the majority of the genotypes were susceptible and only 22 genotypes (6.6%) were resistant to all four P. triticina races. The GWAS detected 11 QTL on nine chromosomes for LR resistance. Of these, six QTL were identified in the vicinity of known genes or QTL; therefore, more studies are warranted to determine their relationship. Five QTL (QLr.uga-1AL, QLr.uga-4AS, QLu.uga-5AS, QLr.uga-5AL, and QLr.uga-7AS) were identified on genomic regions where no LR resistance genes have been identified in wheat, representing potential novel loci for LR resistance. The highly resistant wheat genotypes and novel QTL reported in this study could be used in breeding programs to improve LR resistance.
新的毒力强的小麦条锈菌菌株的出现需要不断寻找新的抗性来源，以对抗叶锈病（LR）。本研究鉴定了 22 个对四种小麦条锈菌菌株具有抗性的小麦基因型。全基因组关联研究检测到 11 个与 LR 抗性相关的数量性状位点；其中 5 个位于尚未检测到 LR 抗性基因的基因组区域。全球小麦（Triticum aestivum L.）生产正受到多种生物和非生物因素的挑战。由 Puccinia triticina 引起的叶锈病（LR）是全球小麦生产的主要生物限制因素。遗传抗性是控制 LR 最有效和最具成本效益的方法。迄今为止，已经鉴定了 79 个 LR 抗性基因，但每年新的毒力强的小麦条锈菌菌株的频繁出现要求不断寻找具有新的数量性状位点（QTL）或基因的新抗性来源。本研究的目的是鉴定美国东南部当前流行的小麦条锈菌菌株的潜在有效抗性新来源，并通过全基因组关联研究（GWAS）方法对与 LR 抗性相关的基因组位点进行作图。对 331 个不同的小麦基因型对四个流行的小麦条锈菌菌株（MFGKG、MBTNB、MCTNB 和 TCRKG）的评价表明，大多数基因型是易感性的，只有 22 个基因型（6.6%）对所有四个小麦条锈菌菌株具有抗性。GWAS 在九个染色体上检测到 11 个与 LR 抗性相关的 QTL。其中，在已知基因或 QTL 附近鉴定了 6 个 QTL；因此，需要进一步研究以确定它们之间的关系。在小麦中尚未鉴定到 LR 抗性基因的五个 QTL（QLr.uga-1AL、QLr.uga-4AS、QLu.uga-5AS、QLr.uga-5AL 和 QLr.uga-7AS）在基因组区域被鉴定出来，代表了 LR 抗性的潜在新位点。本研究中报道的高抗小麦基因型和新的 QTL 可用于改良 LR 抗性的育种计划。
