Department of Cell Biology and Genetics, University of Alcalá, Campus Universitario, 28871 Alcala de Henares, Madrid, Spain.
Genome. 2009 Jul;52(7):608-19. doi: 10.1139/G09-038.
Two previously isolated resistance gene analogs (RGAs) of oat have been located as RFLPs in the reference map of Avena byzantina 'Kanota' x Avena sativa 'Ogle' in regions either homologous or homoeologous to loci for resistance to Puccinia coronata, the causal agent of crown rust. In this study, the RGAs were mapped in two recombinant inbred line (RIL) populations that segregate for crown rust resistance: the diploid Avena strigosa x Avena wiestii RIL population (Asw), which has been used for mapping the complex locus PcA, and the hexaploid MN841801-1 x Noble-2 RIL population (MN), in which QTLs have been located. To obtain single-locus markers, RGAs were converted to sequence tagged site (STS) markers using a procedure involving extension of the original RGA sequence lengths by PCR genome walking, amplification and cloning of the parental fragments, and identification of single nucleotide polymorphisms. The procedure successfully obtained STSs from different members of the L7M2 family of sequences, the initial NBS of which have nucleotide similarities of >83%. However, for RGA III2.18, the parental lines were not polymorphic for the STSs assayed. A sequence characterized amplified region (SCAR) marker with features of an RGA had been previously identified for gene Pc94. This marker was also mapped in the above RIL populations. Markers based on RGA L7M2 co-localized with markers defining the QTL Prq1a in linkage group MN3, and were located 15.2 cM from PcA in linkage group AswAC. The SCAR marker for Pc94 was also located in the QTL Prq1a but at 39.5 cM from PcA in AswAC, indicating that the NBS-LRR sequence represented by this marker is not related to PcA. L7M2 was also excluded as a member of the PcA cluster, although it could be an appropriate marker for the Prq1a cluster if chromosome rearrangements are postulated.
两个先前分离的燕麦抗性基因类似物（RGAs）已被定位为在 Avena byzantina 'Kanota' x Avena sativa 'Ogle' 的参考图谱中的 RFLPs，这些图谱在与 Puccinia coronata（导致冠锈病的病原体）抗性相关的基因座的同源或同系物区域。在这项研究中，RGAs 被映射到两个 segregate 用于冠锈病抗性的重组自交系（RIL）群体中：二倍体 Avena strigosa x Avena wiestii RIL 群体（Asw），该群体已用于映射复杂基因座 PcA，以及六倍体 MN841801-1 x Noble-2 RIL 群体（MN），其中已经定位了 QTLs。为了获得单基因座标记，使用涉及通过 PCR 基因组行走扩展原始 RGA 序列长度、扩增和克隆亲本片段以及鉴定单核苷酸多态性的程序，将 RGAs 转换为序列标记位点（STS）标记。该程序成功地从 L7M2 序列家族的不同成员中获得了 STSs，其初始 NBS 的核苷酸相似性大于 83%。然而，对于 RGA III2.18，供试亲本系的 STSs 没有多态性。先前已经为基因 Pc94 鉴定了具有 RGA 特征的序列特征扩增区域（SCAR）标记。该标记也被映射到上述 RIL 群体中。基于 RGA L7M2 的标记与定义 MN3 连锁群中 QTL Prq1a 的标记共定位，并位于 AswAC 连锁群中 PcA 处 15.2 cM。Pc94 的 SCAR 标记也位于 QTL Prq1a 中，但在 AswAC 中距离 PcA 39.5 cM，表明该标记代表的 NBS-LRR 序列与 PcA 无关。尽管如果假设染色体重排，L7M2 也可以作为 PcA 簇的合适标记，但它也被排除在 PcA 簇之外。
