Ellis J G, Lawrence G J, Luck J E, Dodds P N
Commonwealth Scientific and Industrial Research Organization-Plant Industry, GPO Box 1600, Canberra, ACT, 2601, Australia.
Plant Cell. 1999 Mar;11(3):495-506. doi: 10.1105/tpc.11.3.495.
Thirteen alleles (L, L1 to L11, and LH) from the flax L locus, which encode Toll/interleukin-1 receptor homology-nucleotide binding site-leucine-rich repeat (TIR-NBS-LRR) rust resistance proteins, were sequenced and compared to provide insight into their evolution and into the determinants of gene-for-gene resistance specificity. The predicted L6 and L11 proteins differ solely in the LRR region, whereas L6 and L7 differ solely in the TIR region. Thus, specificity differences between alleles can be determined by both the LRR and TIR regions. Functional analysis in transgenic plants of recombinant alleles constructed in vitro provided further information: L10-L2 and L6-L2 recombinants, encoding the LRR of L2, conferred L2 resistance specificity, and an L2-L10 recombinant, encoding the LRR of L10, conferred a novel specificity. The sequence comparisons also indicate that the evolution of L alleles has probably involved reassortment of variation, resulting from accumulated point mutations, by intragenic recombination. In addition, large deletion events have occurred in the LRR-encoding regions of L1 and L8, and duplication events have occurred in the LRR-encoding region of L2.
对亚麻L位点的13个等位基因（L、L1至L11以及LH）进行了测序和比较，这些等位基因编码Toll/白细胞介素-1受体同源核苷酸结合位点富含亮氨酸重复序列（TIR-NBS-LRR）的抗锈蛋白，以深入了解它们的进化以及基因对基因抗性特异性的决定因素。预测的L6和L11蛋白仅在LRR区域存在差异，而L6和L7仅在TIR区域存在差异。因此，等位基因之间的特异性差异可由LRR和TIR区域共同决定。对体外构建的重组等位基因在转基因植物中的功能分析提供了进一步信息：编码L2的LRR的L10-L2和L6-L2重组体赋予L2抗性特异性，而编码L10的LRR的L2-L10重组体赋予一种新的特异性。序列比较还表明，L等位基因的进化可能涉及因基因内重组导致的累积点突变所产生的变异重排。此外，L1和L8的LRR编码区域发生了大的缺失事件，L2的LRR编码区域发生了重复事件。
