普通小麦SSR和EST-SSR引物对冰草通用性的比较分析

Comparison of Transferability of Common Wheat SSRs and EST-SSRs to Agropyron cristatum L.

选用定位于普通小麦7个部分同源群的534对SSR引物和351对EST-SSR引物分别对普通小麦品种‘Fukuho’和四倍体冰草‘Z559’的基因组DNA进行扩增,结果显示:有475对(89.0%)SSR引物和314对(89.5%)EST-SSR引物对‘Fukuho’能有效扩增,226对(42.3%)SSR和258对(73.5%)EST-SSR引物对‘Z559’能有效扩增,表明小麦EST-SSR对冰草的通用性明显高于SSR;扩增强带比率SSR和EST-SSR引物分别为76.1%、84.1%,说明小麦EST-SSR在冰草上扩增带的质量亦优于SSR。选择上述在‘Fukuho’和‘Z559’基因组DNA之间有多态性扩增且带谱清晰的SSR和EST-SSR引物各60对,对‘Fukuho’、‘中国春’、‘北京8号’和二、四、六倍体冰草‘Z804’、‘Z559’、‘Z1075’的基因组DNA再行PCR扩增,结果显示,40对(66.7%)SSR和22对(36.7%)EST-SSR引物在‘Fukuho’、‘中国春’和‘北京8号’间扩增产物表现多态性,且前者高于后者;50对(83.3%)SSR和52对(86.7%)EST-SSR引物在冰草‘Z804’、‘Z559’和‘Z1075’间扩增产物表现多态性,两者相当。通用性、多态性和扩增强带比率综合比较表明,普通小麦EST-SSR和SSR经筛选虽都能转用于冰草,但两者相比EST-SSR更优。

534 and 351 pairs of SSR and EST-SSR primers mapped on 7 homeologous groups of common wheat were initially used to amplify the genomic DNA of a representative common wheat cultivar,Fukuho and a tetraploid accession,Z559 from Agropyron cristatum L. It was found that 475（89.0%）SSRs and 314 （89.5%）EST-SSRs primer pairs brought detectable amplification on the genomic DNA of Fukuho respectively, while 226 （42.3 % ） SSRs and 258 （73.5 %） EST-SSRs primer pairs gave evident amplification on the genomic DNA of Z559. The results indicated that EST-SSRs had higher transferability to A. cristatum than that of genomic SSRs. Additionally, stronger bands were more frequently exhibited on the electrophoresis patterns of PCR products driven by EST-SSR primers compared with SSR primers. A subset of 60 primer pairs each of SSRs and EST-SSRs resulted in CIear bands and polYmorphisms on Fukuho and Z559 PCRpatterns was then chosen to further test the polymorphisms among three common wheat cv. ,Fukuho,Chinese Spring and Beijing 8 and among three A. cristatum accessions,Z804（2n=2x,PP）,Z559（2n=4x,PP- PP） and Z1075（2n=6x,PPPPPP）. 40 （66. 7%）SSRs and 22 （36.7%） EST-SSRs primer pairs detected polymorphisms among the three common wheat cultivars, while 50 （83.3 %） SSRs and 52 （86.7 %） ESTSSRs primer pairs amplified the genomic DNAs of the three A. cristatum accessions differently. Based on transferability,band intensity and polymorphisms on PCR patterns,it was obviously shown that common wheat EST-SSRs had higher transferability to A. cristatum than that of SSRs though both of them could do after screening. Thus, the utility of EST-SSR markers should be superior to that of SSRs in the studies related to A. cristatum.