• Horticultural Science & Technology
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• v.31 no.6
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• pp.772-781
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• 2013

The objective of this study was to develop simple sequence repeat (SSR) markers from expressed sequence tags (EST) of lettuce (Lactuca sativa) and identify 9 germplasms from 3 wild species of lettuce and 61 commercial cultivars using the developed EST-SSR markers. A total of 81,330 lettuce ESTs from NCBI databases were used to search for SSR and 4,229 SSR loci were identified. The highest proportion (59.12%, 2500) was represented by trinucleotide, followed by dinucleotide (29.70%, 1256) and hexanucleotide (6.62%, 280) among SSR repeat motifs. Totally 474 EST-SSR primers were developed from EST and a random set of 267 primers was used to assess the genetic diversity among 9 germplasms and 61 cultivars. Out of 267 primers, 47 EST-SSR markers showed polymorphism between 7 cultivars. Twenty-six EST-SSR markers among 47 EST-SSR markers showed high polymorphism, reproducibility, and band clearance. The relationship between 26 markers genotypes and 70 accessions was analyzed. Totally 127 polymorphic amplified fragments were obtained by 26 EST-SSR markers and two to nine SSR alleles were detected for each locus with an average of 4.88 alleles per locus. Average polymorphism information content was 0.542, ranging from 0.269 to 0.768. Genetic distance of clusters ranged from 0.05 to 0.94 between 70 accessions and dendrogram at a similarity of 0.34 gave 7 main clusters. Analysis of genetic diversity revealed by these 26 EST-SSR markers showed that the 9 germplasms and 61 commercial cultivars were discriminated by marker genotypes. These newly developed EST-SSR markers will be useful for cultivar identification and distinctness, uniformity and stability test of lettuce.

• Korean Journal of Plant Resources
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• v.26 no.4
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• pp.491-502
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• 2013

Persimmon (Diospyros kaki Thunb) fruit is one of the most important fruit and have been cultivated from ancient times in Korea. In this study, we found 16 EST-SSR markers that contained one or more EST-SSR sites from 246 cDNA sequences. The developing of EST-SSR marker analysis from 42 persimmon cultivars was compared by genetic relationships and morphological relationships using 6 qualitative traits (fruit related 6 traits) and 19 quantitative traits (flower related 19 traits). In this study, 25 primer sets were tested to identify PCR polymorphism and 14 potential EST-SSR primer pairs were selected. The result of morphological relationship EST-SSR marker analysis showed that the coefficient 0.02 was difficult to categorize in several groups. And then, coefficient 0.77 of genetic relationship showed that the group was classified as four groups. The result of correlation distance between genetic relationship and morphological relationship were investigated was low significance (-0.03). Our results also provided an optimized method for improvement of breeding efficiency and introduce of superior character at persimmon cultivars using EST-SSR markers which was useful for further investigation.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.74-74
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• 2018

Little millet (Panicum sumatrense) is well known for its salt and drought stress tolerance and high nutritional value, but very limited knowledge of genetic variation and genomic information is available. This study was to develop highly polymorphic EST-SSR markers based on cross-species transferability of derived SSRs from switchgrass EST databases and characterize newly developed EST - SSRs to better understand the genetic diversity of collected 37 germplasm accessions of little millet. A total of 779 primer pairs were designed from the 22,961 EST sequences of switchgrass (Pancium virgatum), of which 48 EST - SSR markers were developed based on the trials of transferability of these primers in little millet. The EST - SSR amplicons showed reproducible single band polymorphism and produced a total of 160 alleles with an average of 3.3 alleles per locus in 37 accessions of little millet. T he average values of expected and observed heterozygosities were 0.266 and 0.123, respectively. T he polymorphic information content (PIC) values were observed in range of 0.026 to 0.549 with an average of 0.240. The genetic relatedness among the little millet accessions was evaluated by neighbor-joining dendrogram, which grouped all accessions into two distinct groups. The validation thus demonstrated the utility of the switchgrass EST - SSR markers in assessing genomic relationships in little millet. T he findings from this study could be useful for designing strategies for the identification of diverse germplasm for conservation and future molecular breeding programs for little millet.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.43-43
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• 2019

The collection, evaluation and conservation of crop germplasm have been treated as one of the basics to breeding program. An understanding of genetic relationships among germplasm resources is vital for future breeding process like yield, quality, and resistance. In the present study, EST-SSR markers were employed to assess the polymorphism and genetic diversity of 192 accessions of Proso millet preserved in the National Agrobiodiversity Center of RDA. We evaluated the efficiency of EST-SSR markers developed for proso millet species. A total of 98 alleles were detected with an average allele number of 4.5 per locus among 192 proso millet millet accessions using 22 EST-SSR markers. The averaged values of gene diversity ($H_E$) and polymorphism information content (PIC) for each EST-SSR marker were 0.362 and 0.404 within populations, respectively. Our results showed the moderate level of the molecular diversity among the proso millet accessions from diverse countries. A phylogenetic tree revealed three major groups of accessions that did not correspond with geographical distribution patterns with a few exceptions. The less correlation between the clusters and their geographic location might be considered due to their type difference. Our study provided a better understanding of genetic relationships among various germplasm collections, and it could contribute to more efficient utilization of valuable genetic resources. The EST-SSR markers developed here will serve as a valuable resource for genetic studies, like linkage mapping, diversity analysis, quantitative trait locus/association mapping, and molecular breeding.

• Korean Journal of Medicinal Crop Science
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• v.20 no.4
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• pp.277-285
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• 2012

In this study, Expressed Sequence Tag-Simple Sequence Repeat (EST-SSR) analyses were used to clarify the genetic polymorphisms among Korean ginseng cultivars and breeding lines and to classify them into distinct genetic groups. Polymorphic and reproducible bands were produced by 14 primers out of total 30 primers used in this study. Fourteen EST-SSR loci generated a total of 123 bands. Amplified PCR products showed the highly reproducible banding patterns at 110~920 bp. The number of amplified bands for each EST-SSR primers ranged from 2 to 19 with a mean of 8.8 bands. P26 and P35 primers showed 13 and 12 banding patterns, respectively. The number of alleles for each EST-SSR locus ranged from 1.67 to 2.00 with a mean of 1.878 alleles. P34 and P60 primers showed the highest and the lowest genetic polymorphism, respectively. Cluster analysis based on genetic similarity estimated by EST-SSR markers classified Korean cultivars and breeding lines into 4 groups. Group included Gopoong and Chunpoong and 9 breeding lines (55%), group included 2 breeding lines (10%), group included 3 breeding lines (15%), group included Gumpoong and 3 breeding lines (20%). Consequently, the EST-SSR marker developed in this study may prove useful for the evaluation of genetic diversity and differentiation of Korean ginseng cultivars and breeding lines.

• Journal of Plant Biotechnology
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• v.46 no.3
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• pp.158-164
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• 2019

Molecular characterization of different genotypes reveals accurate information about the degree of genetic diversity that helps to develop a proper breeding program. In this study, a total of 30 EST-based simple sequence repeat (EST-SSR) markers derived from trumpet lily (Lilium longiflorum) were used across 11 native lily species for their genetic relationship. Among these 30 markers, 24 SSR markers that showed polymorphism were used for evaluation of diversity spectrum. The allelic number at per locus ranged from 1 at SSR2 locus to 34 alleles at SSR15 locus, with an average of 11.25 alleles across 24 loci observed. The polymorphic information content, PIC, values ranged from 0.0523 for SSR9 to 0.9919 for SSR2 in all 24 loci with an average of 0.3827. The allelic frequency at every locus ranged from 0.81% at SSR2 locus to 99.6% at SSR14 locus. The pairwise genetic dissimilarity coefficient revealed the highest genetic distance with a value of 81.7% was in between L. dauricum and L. amabile. A relatively closer genetic distance was found between L. lancifolium and L. dauricum, L. maximowiczii and L. concolor, L. maximowiczii and L. distichum (Jeju), L. tsingtauense and L. callosum, L. cernuum and L. distichum (Jeju ecotype), of which dissimilarity coefficient was 50.0%. The molecular fingerprinting based on microsatellite marker could serve boldly to recognize genetically distant accessions and to sort morphologically close as well as duplicate accessions.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.45-45
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• 2020

A large number of expressed sequence tags (ESTs) in public databases have provided an opportunity for the systematic development of simple sequence repeat (SSR) markers. EST-SSRs derived from conserved coding sequences show considerable cross-species transferability in related species. In the present study, we assessed the utility of foxtail millet EST-SSRs in barnyard millet. A total of 312 EST-SSRs of foxtail millet were tested using 84 Echinochloa crus-galli germplasm accessions; a high rate of transferability (62%) and 46 primer sets (13%) were shown the polymorphism in barnyard millet. The 13% of functional EST-SSRs) was demonstrated between cereals and barnyard millet. SSR marker profile data were scored for the computation of pairwise distances as well as a Neighbor Joining (NJ) tree of all the genotypes. The averaged values of gene diversity (H_E) and polymorphism information content (PIC) were 0.213 and 0.179 within populations, respectively. The 84 barnyard millet germplasm accessions were divided into five different groups, which agreed well with their geographical origins. The exotic 12 accessions of India type barnyard millet (E. frumentacea) were all separated form Korean local collection genotype. The present results provide evidence of divergence between cultured and wild type barnyard, as a millet and grass. The polymorphic SSR markers indicated in this study were of great value in analysis of genetic diversity that can be further used for crop improvement through breeding.

• Journal of agriculture & life science
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• v.46 no.4
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• pp.85-92
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• 2012

This study was conducted to develop a set of EST-SSR marker for the purity test of commercial F1 hybrid cultivars in the watermelon. A total of 353 EST-SSR were selected and tested on seven F1 cultivars and their 11 parental lines achieved from NH Seeds Inc., Korea. Among tested 96 primer sets, WMU0056 for 'Orange', WMU0400 for 'Heukbo', WMU0056 and WMU0400 for 'Sindong', and WMU0056 and WMU0400 for 'Serona' revealed polymorphisms between the parental lines and heterozygosity from these F1 cultivers. Of 122 primer sets tested for 'Haedong', WMU0056, WMU0400, WMU0580, WMU1211, WMU4136, and WMU448 showed polymorphisms that were appropriate for the F1 purity test. WMU0056 and WMU0400 can be useful for 'Haedong', as well. Relatively low polymorphisms between parental lines were detected for 'Kulnara'(5%) and 'Hwangpea'(2%), and therefore, all 353 primer sets were tested on these cultivars. As the result, WMU5339 and WMU7003 were found to be useful for the F1 purity test in 'Kulnara' and 'Hwangpea', respectively. Using these EST-SSR markers developed by ICuGI, hybridity of the seeds for four F1 cultivars produced from farmers was evaluated, and levels of the F1 purity higher than 97.5% was observed from all seed populations. Our results indicated that the watermelon EST-SSR marker information posted in ICuGI could be utilized for developing codomiant and locus-specific markers that are highly effective for the F1 purity test.

• Korean Journal of Plant Resources
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• v.30 no.3
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• pp.287-297
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• 2017

Little millet (Panicum sumatrense) is well known for its salt and drought stress tolerance and high nutritional value, but very limited knowledge of genetic variation and genomic information is available. In this study, a total of 779 primer pairs were designed from the 22,961 EST sequences of switchgrass (Pancium virgatum), of which 48 EST-SSR markers were developed based on the trials of transferability of these primers in little millet. The EST-SSR amplicons showed reproducible single band polymorphism and produced a total of 160 alleles with an average of 3.3 alleles per locus in 37 accessions of little millet. The average values of expected and observed heterozygosities were 0.266 and 0.123, respectively. The polymorphic information content (PIC) values were observed in range of 0.026 to 0.549 with an average of 0.240. The genetic relatedness among the little millet accessions was evaluated by neighbor-joining dendrogram, which grouped all accessions into two distinct groups. The validation thus demonstrated the utility of the switchgrass EST-SSR markers in assessing genomic relationships in little millet. The findings from this study could be useful for designing strategies for the identification of diverse germplasm for conservation and future molecular breeding programs for little millet.

• Korean Journal of Medicinal Crop Science
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• v.21 no.6
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• pp.444-454
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• 2013

The development of random amplified polymorphic DNA (RAPD) and expressed sequence tag-derived simple sequence repeats (EST-SSRs) provided a useful tool for investigating Korean ginseng genetic diversity. In this study, 18 polymorphic markers (7 RAPD and 11 EST-SSR) selected to assess the genetic diversity in 31 ginseng accessions (11 Korean ginseng cultivars and 20 breeding lines). In RAPD analysis, a total of 53 unique polymorphic bands were obtained from ginseng accessions and number of amplicons ranged from 4 to 11 with a mean of 7.5 bands. Pair-wise genetic similarity coefficient (Nei) among all pairs of ginseng accessions varied from 0.01 to 0.32, with a mean of 0.11. On the basis of the resulting data, the 31 ginseng accessions were grouped into six clusters. As a result of EST-SSR analysis, 11 EST-SSR markers detected polymorphisms among the 31 ginseng accessions and revealed 49 alleles with a mean of 4.45 alleles per primer. The polymorphism information content (PIC) value ranged from 0.06 to 0.31, with an average of 0.198. The 31 ginseng accessions were classified into five groups by cluster analysis based on Nei's genetic distances. Consequently, the results of ginseng-specific RAPD and EST-SSR markers may prove useful for the evaluation of genetic diversity and discrimination of Korean ginseng cultivars and breeding lines.