真藓科植物ISSR-PCR反应体系的优化及ISSR指纹图谱的初步构建

目的]试图通过ISSR指纹图谱的构建,为真藓科（Bryacae）植物的种类鉴定提供分子分析数据。方法]为获得标准试验程序,首先利用正交试验设计的方法对真藓科植物的ISSR-PCR反应的5因素（Mg2＋、dNTPs、引物、DNA模板、TaqDNA聚合酶）4水平进行试验。结果]最适扩增条件是：在20μl PCR反应体系中,5ng模板DNA,0.2μmol/L引物,2.25mmol/LMgCl2,0.6U Taq DNA聚合酶,0.4mmol/LdNTPs。最适退火温度为48～50℃。利用此结论使用6条ISSR引物对14种真藓科及相关的提灯藓科（Mniaceae）植物分别进行PCR扩增,共扩增出86条带,多态性带为86条,多态率达100%。根据扩增结果进行NJ聚类分析,得到的支序图呈星状。结论]ISSR指纹能够在种级分类水平提供适度的多态性,利用引物UBC-808、811以及826构建的ISSR指纹图谱能够区分所有供试植物,为利用ISSR指纹技术解决真藓科植物种级水平分类关系问题时提供了分子辅助证据的可行性。

Optimization of ISSR-PCR Reaction System and Preliminary Construction of ISSR Fingerprinting of Some Species in Bryaceae

Objective] The aim was to provide molecular basis for the identification of species in the moss family Bryaceae by the construction of inter-simple sequence repeats (ISSR) fingerprinting. Method] In order to seek standardizing PCR reaction set-up, an orthogonal design was used to optimize ISSR-PCR amplification system of Bryaceae in five factors (Mg2+, dNTPs, primer, DNA template, Taq DNA polymerase) at four levels respectively. Result] A suitable ISSR reaction system was obtained, namely: 20 μl reaction system containing 5 ng of DNA template, 0.2 μmol/L primer, 2.25 mmol/L MgCl2, 0.6 U of Taq DNA polymerase, 0.4 mmol/L dNTPs. Proper annealing temperature was found at 48-50 ℃.The above system and six ISSR-PCR primers were used for the PCR amplification of 14 samples from Bryaceae and the related species in Mniaceae. A total of 86 bands were amplified, all showed polymorphism. NJ cluster analysis showed a star-shaped cladogram. Conclusion] The results manifested that ISSR fingerprinting could provide the appropriate degree of polymorphism at low taxonomic level, so it would be a useful tool to provide additional evidence for resolving taxonomic relationships at the species level of Bryaceae.