转基因水稻T—DNA侧翼序列的扩增与分析

利用现有的转抗白叶枯病基因Xa21的水稻材料，通过TAIL－PCR技术扩增出携带Xa21基因的T－DNA的侧翼序列，对24个有效扩增片段的序列分析结果表明，其中14个侧翼序列是水稻DNA，9个含载体主干序列，1个是外源基因Xa21片段，14个T－DNA侧翼的水稻DNA序列与直接转化法外源基因整合位点的基因组序列具有不同的特点，这些T－DNA在水稻染色体上整合后其两端序列的特点类似于在转基因双子叶植物中观察到的现象，在含主干序列的侧翼序列（37．5％，9／24），中，载体主干序列是以不同的类型出现的。

Amplification and Analysisof T-DNA Flanking Sequences in Transgenic Rice

Rice transformation mediated by Agrobacterium tumefaciens has technically matured to some extent, but the mechanics of T-DNA integration in transgenic rice remains largely unknown. Using thermal asymmetric interlaced PCR (TAIL-PCR), we analyzed the flanking sequences of T-DNAs in transgenic rice plants, in which the resistance gene for rice bacterial blight disease, Xa21, had been integrated stably.Sequence analysis of 24 fragments amplified by TAIL-PCR showed that of them 14 were rice genomic DNA, 9 contained vector backbone sequences, and one was a fragment of the exogenous gene Xa21. The characteristics of the 14 rice genomic DNA sequences at T-DNA integrated sites are significantly different from those of the reported rice genomic sequences into which exogenous genes were integrated through direct DNA transformation methods. T-DNA border sequences integrated in rice genome have similar features as those integrated in dicotyledonous genomes. In the backbonecontaining flanking sequences (37.5%, 9/24) vector backbones appeared in different types.