普通野生稻中NBS同源序列的克隆和分析

Molecular Cloning and Analysis of Nucleotide Binding Site Homologues in Oryza rufipogon

已知的植物抗病基因大多数具有核苷酸结合位点（ＮＢＳ）和富含亮氨酸重复区（ＬＲＲ）．根据 ＮＢＳ的保守区设计引物，应用聚合酶链式反应（ＰＣＲ），从普通野生稻基因组中克隆了４个不 同的ＮＢＳ同源序列（ＯＳＮＢＡ１～ＯＳＮＢＡ４）．同源性比较显示它们均与非ＴＩＲ类的ＮＢＳ序列 相似．其中，ＯＳＮＢＡ１与双子叶植物拟南芥的ＲＰＳ２基因更接近；ＯＳＮＢＡ２～ＯＳＮＢＡ ４与单子叶植物水稻的ＸＡ１、ＲＰＲ１基因更相似．

To date the majority of known plant disease-resistance genes are featured with a nucleotide-binding site (NBS) and leucine-rich repeats(LRR). By polymerase c hain reaction with the degenerate primers designed to the conserved motifs withi n NBS, four distinct NBS homologues ( OSNBA 1 ～OSNBA 4) were cloned from Oryza rufipogon . All of them showed high homology to the non-TIR type of NBS sequences in plant genomes. The genetic distance analysis revealed that OSNBA 1 was closer to RPS2 from Arabidopsis while the others w ere closer to XA 1 and RPR 1 from rice.