用克隆池PCR法筛选小麦-簇毛麦易位系6VS/6AL基因组TAC文库获得抗病基因候选克隆

用根据抗病基因保守区设计的一对简并性引物，从小麦－簇毛麦易位系6VS／6AL cDNA中PCR扩增获得一个具有抗病基因核苷酸结合位点（Nucleotide binding site,NBS）结构特点的DNA片段克隆N7。从小麦－簇毛麦易位系6VS／6AL基因组TAC（Transformation-competent artificial chromosome,TAC）文库的22块96孔板提取所有2112个克隆池（每个池含约1000个克隆）的质粒，再根据N7的核苷酸序列设计一对特异引物，用克隆池PCR（pooled PCR)法经分级筛选从文库中获得一个阳性克隆。以N7为探针，通过Southern杂交证实了该TAC克隆为真正含有抗病候选基因的克隆。研究结果表明克隆池PCR法对克隆数目巨大的基因组文库的筛选很有效。

Screening for Resistance Gene Candidate from a Genomic TAC Library of Triticum aestivum- Haynaldia villosa Translocation Line 6VS/6AL by Pooled PCR

A pair of degenerate primers were designed based on NBS (nucleotide binding site, NBS) domain of resistance(R) gene and used to perform PCR with cDNA from the translocation line 6VS/6AL of Triticum aestivum-Haynaldia villosa. A clone (N7) characterized with NBS was obtained by sequencing analysis. Two specific primers were designed from the N7 sequence and used to screen a genomic TAC (transformation-competent artificial chromosome, TAC) library of 6VS/6AL consisting of ca. 2 x 10(6) clones. The library was stored as clone pools in twenty-two 96-well plates, each well containing approximately 1000 TAC clones. TAC plasmids were prepared from all the 2112 pools. Using a pooled PCR screening procedure, a positive TAC clone having a 40 kb insert was obtained. The positive clone was confirmed by Southern hybridization with the NBS fragment as a probe. The results indicate that the pooled PCR method is effective for screening of genomic libraries having large number of clones.