Expression and genome organization of resistance gene analogs in soybean
Expression and genome organization of resistance gene analogs in soybean
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DOI：
10.1139/gen-43-1-86
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发表时间：
2000-02-01
期刊：
影响因子：
3.1
通讯作者：
Shoemaker, RC
中科院分区：
文献类型：
--
作者：
Graham, MA;Marek, LF;Shoemaker, RC
克隆植物抗病基因的序列分析揭示了一些保守结构域。研究人员利用这些结构域扩增了大豆和其他作物的类似序列——抗性基因类似物（RGAs）。其中许多rga与已知的抗性基因非常接近。虽然这项技术在鉴定潜在的抗病基因位点方面很有用，但从一组同源基因中鉴定功能性抗性基因需要来自这些保守结构域之外的序列信息。为了研究RGA的表达并确定其与其他植物抗性基因的相似程度，用RGA类特异性探针杂交筛选了两个大豆cDNA文库（根和上胚轴）。在每个文库中检测与RGA探针杂交的cdna。鉴定出两种类型的cdna。一种是全长型，含有多个抗病基因（r基因）特征。另一种类型在这些签名中包含了一些删除。cDNA克隆序列分析表明它们位于toll -白细胞介素-1受体、核苷酸结合域和富含亮氨酸的抗病基因重复序列家族。利用lrr的3prime末端的克隆特异性引物，我们能够将两个cDNA克隆（LM6和MG13）映射到已知跨越抗病基因簇的BAC contig上。
Sequence analysis of cloned plant disease-resistance genes reveals a number of conserved domains. Researchers have used these domains to amplify analogous sequences, resistance gene analogs (RGAs), from soybean and other crops. Many of these RGAs map in close proximity to known resistance genes. While this technique is useful in identifying potential disease resistance loci, identifying the functional resistance gene from a cluster of homologs requires sequence information from outside of these conserved domains. To study RGA expression and to determine the extent of their similarity to other plant resistance genes, two soybean cDNA libraries (root and epicotyl) were screened by hybridization with RGA class-specific probes. cDNAs hybridizing to RGA probes were detected in each library. Two types of cDNAs were identified. One type was full-length and contained several disease-resistance gene (R-gene) signatures. The other type contained several deletions within these signatures. Sequence analyses of the cDNA clones placed them in the Toll-Interleukin-1 receptor, nucleotide binding domain, and leucine-rich repeat family of disease-resistance genes. Using clone-specific primers from within the 3prime end of the LRRs, we were able to map two cDNA clones (LM6 and MG13) to a BAC contig that is known to span a cluster of disease-resistance genes.