新麦草种质遗传多样性的ISSR分析

利用ISSR标记对15份新麦草(Psathyrostachys juncea)种质资源进行遗传多样性检测.为获得稳定的新麦草ISSR反应体系,对反应条件中的dNTP、Taq酶浓度、引物浓度、Mg_(2+)浓度等因子进行了优化,建立起的最佳反应体系为:25 μL的反应体系中含有dNTP 2.5 μL、Taq酶0.2 μL、Primers 1 μL、Mg~(2+)1.5 μL、2.5 μL 10×Buffer、2 μL模板DNA和ddH2O 15.3 μL.ISSR标记结果显示,筛选出的重复性好、谱带清晰的ISSR引物8条,共获得84个扩增位点,其中多态性位点72个,多态性比率(PPB)为85.7%.通过遗传相似系数(GS)的计算,供试种质材料间的GS值在0.440 5～0.904 8之间,表现出丰富的遗传多样性.通过聚类分析,将15份新麦草种质材料划分为四大类,且呈现出一定的地域性分布规律.

Genetic Diversity Analysis of 15 Psathyrostachys juncea Germplasm Resources by ISSR Molecular Marker

The genetic diversities of 15 Psathyrostachys juncea germplasm resources were analyzed by ISSR molecular marker. Based on the basic system, four factors of Taq DNA polymerase, random primers, Mg~(2+) , and dNTPs which affect ISSR-PCR amplifying results of P.juncea were optimized.An optimal ISSR-PCR system including 2.5μL dNTPs,2 μL template DNA,0.2 μL Taq DNA polymerase, 1μL random primers, 1.5 μL Mg~(2+) ,2.5 μL 10×PCR Buffer, 15.3 μL ddH_2O,and the total volume was 25 μL,was established.The results of ISSR marker showed that 8 primers,which could show clearer bands and had good repetition, were selected from 25 primers and detected a total of 84 bands, among which 72 bands were polymorphic. The average percentage of polymorphic bands ( PPB) was 85.7% . According to 0.440 5 -0.904 8 of the GS values,the germplasm and materials of P. juncea showed rich genetic diversity. Based on cluster analysis of the genetic characteristics, 15 P. juncea germplasm could be divided into 4 groups according to the nearest phylogenetic relationship. In most cases, the germplasm and materials from the same country were in the same group and showed the definite rules of geographical distribution.