| Olea europaea L.and Vernicia montana L.belong to the genus Olea of Oleaceae family and the genus Vernicia of Euphorbiaceae family,respectively.O.europaea,as an oil crop with important edible value,is cultivated and spread worldwide,owning very rich germplasm resources.The confusion on the names of olive germplasms has often occurred,which make it difficult to identify germplasms.For V.montana with extremely strong resistant to wilt disease,its seed oil has important industrial value.However,the identification and genetic analysis of V.montana germplasms urgently need to be strengthened due to its short cultivation history and inadequate management of germplasm resources.Simple sequence repeats（SSRs）are excellent molecular markers and have been used for the identification of germplasms and genetic diversity analysis in many plants.In this study,the newly developed genomic-SSR markers identified germplasms and revealed the genetic diversity in O.europaea and V.montana,respectively.The main results are as follows:（1）According to the whole genome of olive provided by NCBI,200 pairs of SSR primers were designed based on trinucleotide SSR loci.21 highly polymorphic genomic SSR markers were selected and developed from these 200 SSR primers by genotyping the SSR loci,covering most chromosomes of olive.These SSR markers well distinguished all the tested 53 olive germplasms,confirming their effectiveness.DNA fingerprints of the 53 olive germplasms were constructed based on the 21 SSR markers.The dendrogram clearly divided the tested germplasms into two main groups,which was also supported by the results of principal coordinate analysis.A total of 31 private alleles were detected in 15olive germplasms at 13 SSR loci,which reflected the genetic diversity within 53 olive germplasms to some extent.Six homonymy cases were also clarified by genetic analysis.（2）The simplified genome of V.montana were assembled by RAD sequencing technology.300 pairs of SSR primers were successfully designed from trinucleotide,tetranucleotide,and pentanucleotide SSR loci based on the genome sequence.17 polymorphic trinucleotide genomic-SSR markers were selected and developed from these 300 SSR primers by genotyping the SSR loci,which well distinguished all the tested 105 accessions of three V.montana populations from different geographical distributions,confirming their effectiveness.DNA fingerprints of the 105 V.montana germplasms were constructed based on the 17 SSR markers.A total of 85 private alleles were detected in 62 germplasms at 15 SSR loci.The FST analysis in AMOVA showed a moderate degree of genetic differentiation within and among the three populations of V.montana;however,the genetic variation within the populations was much higher than that among the populations.Population structure analysis revealed that four different gene pools were present in the tested three populations from different geographical distributions,and there was both evolutionary independence and a relatively high degree of genetic admixture between the populations that was well correlated with the results of UPGMA clustering and PCo A analyses.Taken together,the results indicated that the newly developed genomic-SSR markers in O.europaea and V.montana would be very valuable for the germplasm collection and preservation,especially for the SSR molecular marker-assisted breeding to accelerate the breeding process of new germplasms. |
