目的设计出霍山石斛的位点特异性鉴别引物，仅通过PCR就能对霍山石斛的真伪进行准确鉴别。方法利用石斛属植物基因库中rDNA ITS序列数据库进行同源性比较，在与霍山石斛差异较大的区段设计1对特异性引物，然后对19份石斛属植物DNA模板进行PCR扩增，阳性者即为霍山石斛正品。结果发现在退火温度为60℃时，该引物能把霍山石斛的模板从19份石斛属植物中扩增出来，而其他的石斛属植物均为阴性。结论运用位点特异性鉴别引物成功地对霍山石斛进行PCR鉴别，该鉴别反应重现性好，能在霍山石斛鉴别时发挥重要的作用，与形态学、DNA测序等鉴别方法相比，该方法具有高效、准确、简便、省时等优点。

Objective To design a pair of allele-specific diagnostic primer for authenticating Dendrobium huoshanense from other species of Dendrobium Sw.only by PCR.Methods Based on rDNA ITS sequences database of D.huoshanense and other species of Dendrobium Sw.,an allele-specific diagnostic primer pairs was designed.Diagnostic PCRs were performed using the primer with the total DNAs of 19(original) plants from Dendrobium Sw.as templates.The positive was the genuine.Results When the(annealing) temperature was raised to 60 ℃, the template DNA of D.huoshanense could be amplified whereas the diagnostic PCR of the rest species were all negative.Conclusion The diagnostic PCRs can authenticate D.huoshanense from other species of Dendrobium Sw.efficiently.Compared to the authentication method by sequencing DNA fragments and morphological traits etc.,the allele-specific diagnostic PCR is not only simple with time-saving but also practical and effective.

上海市高等学校科学技术发展基金项目(03DZ02)