The Transferability Of Wheat EST-SSRs Across Other Crops And The Detection Of The Genetic Diversity Of 96 Wheat Materials

EST-SSRs,a new kind of molecular marker ,were based on ESTs(expressed sequence tags) databases.Different from the genomic SSRs,EST-SSRs have gene functions and better transferability.Therefore the development and the application of wheat EST-SSRs will benefit wheat function genomics and comparative genomics undoubtedly.Through PCR amplification and 6% silver-stained polyacrylamide-gel electrophoresis,the transferability of 597 sets of wheat EST-SSRs across maize,rice and soybean,and the genetic diversity of 96 wheat materials are detected.The results of the transferability showed: (1)477,393,371 and 347 of 597 sets amplified in wheat,maize,rice and soybeanrespectively;286 to 389 amplify in two crops;257 to 320 in three as well as 255 in theall four.(2) 80 percents of the 255 universal primers have known functions:of which 30 percents were related with protein destination (more than 92 percents were storage protein),the rests invovled in cell defense,aging,death,metabolism and energy et al. functions.(3) 134,159,134 and 119 of the 255 primers were polymorphic in each two materials of wheat,mai/e,rice and soybean respectively;56 to 92 in two crops and 36 to 51 in three as well as 32 in the all four.(4) The universal EST-SSRs tended to be trinucleotide and mononucleotide. The resaults of the genetic diversity of 96 wheat materials demanstrated:(1) 113 polimorphic bands were detected,on average 3 polymorphic bands for each primers.(2) Some materials had unique bands which can be used to distinguish heterogenous chromosomes and cultivars.(3) The DHs(double haploids) and common wheat were detingushed in two groups clearly;the cultivars' clustering consisted with genealogy basically in spite of some exceptions.(4) As for the diversity of the materials we selected,cultivars were highest,then were foreign cultivars,DHs and landraces.The diversity was different for diferent primers.(5) The diversity of cultivars was different for different provices which was lower than the whole cultivars.(6) The diversity of Chinese cultivars have ever-increasing trends from before 1950s to nowadays.lt increased greatly from 1960s tO 1980s while very slowly since 1980s.