Development Of Mongolia Wheatgrass EST-SSR Primers And Analysis Of Transferability Of Agropyron Geartn

With the continuous innovation of plant sequencing technology and the continuous compression of cost,the database capacity of NCBI-EST data grows exponentially every year,which promotes the batch development and application of EST-SSR labeled primers in many plants.Agropyron mongolicum Keng is a drought-resistant crops.Unfortunately,little genomic information has led to poor knowledge of functional genes related to A.mongolicum Keng,and the genetics research on them were limited.We employed the Illumina techonology to sequence the transcriptome of A.mongolicum Keng,obtain as much sequence information as possible,and systematic annotation was performed to identify in transcripts.Identify SSR loci and screen for polymorphism.The main results were as follows:(1)The present study used Illumina sequencing and de novo transcriptome assembly of A.mongolicum Keng,we obtained approximately 24237250 clean reads.After de novo assembly,75367 unigenes were generated and 37826(50.19%)showed significant similarities versus eight functional protein databases.(2)In addition,4396 expressed sequence tag-simple sequence repeats EST-SSRs were identified with a distribution frequency of 5.8%.Trinucleotide repeat motifs were the most abundant(68.44%),followed by dinucleotide repeat motifs(26.34%).Within the two possible types of repeat,CCG/CGG and AG/CT was the most abundant motifs,containing 41.09%of total SSRs.The number of SSR repeats ranged from 5 to 12,with five repeats(48.59%)representing the most common.(3)Out of 2396 designed EST-SSR primers,400 primers were selected for the development of potential molecular markers.230 pairs of primers could amplify the ideal product(57.5%).Among these markers,89 EST-SSR markers presented a level of genetic diversity,57 pairs of SSR primers with good polymorphism.And the polymorphism information content(PIC)was 0.262-0.657,the percentage of polymorphic loci is:100%.(4)The genetic identity of most A.mongolicum Keng materials varied from 0.5411 to 0.9415,indicating that the genetic relationship between the individuals was closer.(5)In this analysis of 57 pre-screened polymorphic markers,40 markers exhibited amplification in the species.O ur results high light the usefulness of mining sequenced EST collecions of gene-based SSRs to provide molecular markers that can examine genetic relationships and ecological genetics.