利用竞争性PCR筛选无标记Xa21转基因水稻

Application of competitive PCR for screening selectable marker-free Xa21 transgenic rice

PCR是一种简单、迅速、灵敏的检测方法,但假阳性与假阴性却影响了它在常规应用中的准确性。本研究利用竞争性PCR解决无标记Xa21转基因水稻PCR检测中的假阳性与假阴性问题。标记基因潮霉素基因(Hygromycin phosphotransferase,hpt)的竞争模板是外加的日本晴hpt转基因植株基因组DNA,抗白叶枯病基因Xa21的竞争模板是待测水稻内源的位于第11染色体上的Xa21同源基因序列。利用这一方法对双右边界T-DNA载体转化产生的转基因T1代植株进行分析,可以有效地减少或排除假阳性或假阴性样品,选出真正的转基因阳性植株。与常规PCR相比竞争性PCR提高了无标记Xa21转基因植株筛选的准确性。对获得的无标记Xa21转基因植株进行白叶枯抗病鉴定与潮霉素抗性鉴定证实了该方法的可靠性。

Polymerase chain reaction （PCR） is a simple, quick and highly sensitive method. However the accuracy of the conventional PCR assay was often affected by false positives and false negatives. In this study, a protocol competitive PCR was used to reduce the false results in screening for selectable marker-free （SMF） Xa21 transgenic rice plants. The competitive template of Xa21 was the endogenous Xa21 homologous sequence located on chromosome 11. The competitive template of the selectable marker gene, hygromycin phosphotransferase （hpt）, was an additive DNA extracted from hpt transgenic Nipponbare （Oryza sativa L）. Through competitive PCR analysis of transgenic T1 plants produced by double right border binary vector, false positive or false negative samples were effectively diminished, and genuine SMF Xa21 transgenic plants were obviously obtained. Comparing with the conventional non-competitive PCR, competitive PCR increased the accuracy for selecting SMF Xa21 transgenic plants. The results of bacterial blight （BB） resistance tests and hygromycin B resistance assay of SMF Xa21 transgenic plants testified the reliability of this method.