Data from: Introgression of chromosome segments from multiple alien species in wheat breeding lines with wheat streak mosaic virus resistance

Pyramiding of alien-derived Wheat streak mosaic virus (WSMV) resistance and resistance enhancing genes in wheat is a cost-effective and environmentally safe strategy for disease control. PCR-based markers and cytogenetic analysis with genomic in situ hybridisation were applied to identify alien chromatin in four genetically diverse populations of wheat (Triticum aestivum) lines incorporating chromosome segments from Thinopyrum intermedium and Secale cereale (rye). Out of 20 experimental lines, 10 carried Th. intermedium chromatin as T4DL*4Ai#2S translocations, while, unexpectedly, 7 lines were positive for alien chromatin (Th. intermedium or rye) on chromosome 1B. The newly described rye 1RS chromatin, transmitted from early in the pedigree, was associated with enhanced WSMV resistance. Under field conditions, the 1RS chromatin alone showed some resistance, while together with the Th. intermedium 4Ai#2S offered superior resistance to that demonstrated by the known resistant cultivar Mace. Most alien wheat lines carry whole chromosome arms, and it is notable that these lines showed intra-arm recombination within the 1BS arm. The translocation breakpoints between 1BS and alien chromatin fell in three categories: (i) at or near to the centromere, (ii) intercalary between markers UL-Thin5 and Xgwm1130 and (iii) towards the telomere between Xgwm0911 and Xbarc194. Labelled genomic Th. intermedium DNA hybridised to the rye 1RS chromatin under high stringency conditions, indicating the presence of shared tandem repeats among the cereals. The novel small alien fragments may explain the difficulty in developing well-adapted lines carrying Wsm1 despite improved tolerance to the virus. The results will facilitate directed chromosome engineering producing agronomically desirable WSMV-resistant germplasm.

在小麦中聚合外源衍生的小麦条纹花叶病毒（Wheat streak mosaic virus, WSMV）抗性基因及抗性增强基因，是一种经济高效且环境友好的病害防控策略。研究采用基于聚合酶链式反应（Polymerase Chain Reaction, PCR）的分子标记技术结合基因组原位杂交（genomic in situ hybridisation）细胞遗传学分析，在4个遗传背景多样的普通小麦（Triticum aestivum）品系群体中鉴定外源染色质，这些群体均整合有中间偃麦草（Thinopyrum intermedium）与黑麦（Secale cereale, rye）的染色体片段。在20份试验品系中，10份携带以T4DL*4Ai#2S易位形式存在的中间偃麦草染色质；而意外的是，另有7份品系的1B染色体上检测到外源染色质（中间偃麦草或黑麦来源）。本次新鉴定的黑麦1RS染色质可从育种谱系早期传递，且与WSMV抗性提升显著相关。田间试验显示，仅携带1RS染色质的品系即表现出一定抗性；当其与中间偃麦草4Ai#2S染色质共同存在时，抗病效果优于已知抗病品种Mace。多数外源小麦材料携带完整染色体臂，值得关注的是，本研究涉及的品系在1BS臂内发生了臂内重组事件。1BS与外源染色质之间的易位断点可分为三类：(i) 着丝粒处或其邻近区域；(ii) 位于分子标记UL-Thin5与Xgwm1130之间的居间区域；(iii) 朝向端粒，位于Xgwm0911与Xbarc194之间。在高严谨度杂交条件下，标记的中间偃麦草基因组DNA可与黑麦1RS染色质发生杂交，表明谷类作物间存在共享的串联重复序列。这类新型小型外源片段，或可解释为何尽管携带Wsm1的材料对病毒的耐受性有所提升，但培育适应性优良的品系仍存在较大挑战。本研究结果将为定向染色体工程育种提供助力，助力培育兼具优良农艺性状与抗WSMV能力的小麦种质资源。