Juliana Philomin, Rutkoski Jessica E, Poland Jesse A, Singh Ravi P, Murugasamy Sivasamy, Natesan Senthil, Barbier Hugues, Sorrells Mark E
Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell Univ., Ithaca, NY, 14853.
Dep. of Agronomy, Kansas State University, Manhattan, KS, 66506.
Plant Genome. 2015 Jul;8(2):eplantgenome2015.01.0002. doi: 10.3835/plantgenome2015.01.0002.
The partial rust resistance genes Lr34 and Sr2 have been used extensively in wheat (Triticum aestivum L.) improvement, as they confer exceptional durability. Interestingly, the resistance of Lr34 is associated with the expression of leaf tip necrosis (LTN) and Sr2 with pseudo-black chaff (PBC). Genome-wide association mapping using CIMMYT's stem rust resistance screening nursery (SRRSN) wheat lines was done to identify genotyping-by-sequencing (GBS) markers linked to LTN and PBC. Phenotyping for these traits was done in Ithaca, New York (fall 2011); Njoro, Kenya (main and off-seasons, 2012), and Wellington, India (winter, 2013). Using the mixed linear model (MLM), 18 GBS markers were significantly associated with LTN. While some markers were linked to loci where the durable leaf rust resistance genes Lr34 (7DS), Lr46 (1BL), and Lr68 (7BL) were mapped, significant associations were also detected with other loci on 2BL, 5B, 3BS, 4BS, and 7BS. Twelve GBS markers linked to the Sr2 locus (3BS) and loci on 2DS, 4AL, and 7DS were significantly associated with PBC. This study provides insight into the complex genetic control of LTN and PBC. Further efforts to validate and study these loci might aid in determining the nature of their association with durable resistance.
部分抗锈病基因Lr34和Sr2已被广泛用于小麦（普通小麦）改良，因为它们具有非凡的持久性。有趣的是，Lr34的抗性与叶尖坏死（LTN）的表达相关，而Sr2的抗性与假黑颖壳（PBC）相关。利用国际玉米小麦改良中心的秆锈病抗性筛选圃（SRRSN）小麦品系进行全基因组关联作图，以鉴定与LTN和PBC相关的简化基因组测序（GBS）标记。针对这些性状的表型分析在纽约伊萨卡（2011年秋季）、肯尼亚乔洛（2012年主季和非主季）以及印度韦林顿（2013年冬季）进行。使用混合线性模型（MLM），18个GBS标记与LTN显著相关。虽然一些标记与持久抗叶锈病基因Lr34（7DS）、Lr46（1BL）和Lr68（7BL）所在的位点连锁，但在2BL、5B、3BS、4BS和7BS上的其他位点也检测到显著关联。12个与Sr2位点（3BS）以及2DS、4AL和7DS上的位点连锁的GBS标记与PBC显著相关。本研究为LTN和PBC的复杂遗传控制提供了见解。进一步验证和研究这些位点的努力可能有助于确定它们与持久抗性关联的性质。
