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 hybridization 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 twenty experimental lines, ten carried Th. intermedium chromatin as T4DL*4Ai#2S translocations, while, unexpectedly, seven 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: 1) at or near to the centromere, 2) intercalary between markers UL-Thin5 and Xgwm1130, and 3) towards the telomere between Xgwm0911 and Xbarc194. Labelled genomic Th. intermedium DNA hybridized 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.将外源来源的小麦线条花叶病毒（Wheat streak mosaic virus, WSMV）抗病基因及抗病增效基因聚合于小麦中，是一种经济高效且环境友好的病害防控策略。本研究采用基于PCR的分子标记技术结合基因组原位杂交（genomic in situ hybridization）的细胞遗传学分析方法，在4个遗传背景多样的普通小麦（Triticum aestivum）群体中鉴定外源染色质，这些小麦材料整合了中间偃麦草（Thinopyrum intermedium）与黑麦（Secale cereale）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；而令人意外的是，有7份品系在1B染色体上检测到外源染色质（来自中间偃麦草或黑麦）。此次新鉴定的、源自育种谱系早期传递的黑麦1RS染色质，与增强的WSMV抗性显著相关。田间试验结果显示，单独的1RS染色质即具备一定抗性，当其与中间偃麦草4Ai#2S片段组合时，其抗病效果优于已知抗病品种Mace。多数外源小麦品系携带完整染色体臂，值得关注的是，这些品系在1BS臂内发生了臂内重组。1BS与外源染色质之间的易位断点可分为三类：1）着丝粒处或其邻近区域；2）位于标记UL-Thin5与Xgwm1130之间的居间区段；3）靠近端粒、处于Xgwm0911与Xbarc194之间的区段。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，这表明谷类作物中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：尽管携带Wsm1的品系对病毒的耐受性有所提升，但培育适应性优良的小麦品系仍存在较大困难。本研究结果将为定向染色体工程育种提供助力，以培育农艺性状优良的抗小麦线条花叶病毒种质资源。