scholarly journals New eSSR and gSSR markers added to Australian barley maps

2006 ◽  
Vol 57 (9) ◽  
pp. 953 ◽  
Author(s):  
Kerrie L. Willsmore ◽  
Paul Eckermann ◽  
Rajeev K. Varshney ◽  
Andreas Graner ◽  
Peter Langridge ◽  
...  

To enhance genetic maps of barley previously developed in Australia for identifying markers useable in molecular breeding, a new set of simple sequence repeat (SSR) and indel markers was added to the maps. These markers were developed through (i) database mining of barley expressed sequence tag (EST) sequences, (ii) comparative barley-rice genome analysis, and (iii) screening of a genomic library with SSR probes. The primer set selected for this study comprised 216 EST-SSR (eSSR) and 25 genomic SSR (gSSR) markers, which were screened for polymorphism on 4 doubled haploid (DH) or recombinant inbred line (RIL) populations. In total, 81 new markers were added to the maps, with good coverage on all 7 chromosomes, except 6H, which only had 2 new markers added. The marker order of previously published maps was re-evaluated by comparing recombination fractions calculated by 2 methods to discover the best position for each marker. The new SSR markers were then added to the updated maps. Several of these new markers are linked to important barley disease resistance genes such as those for cereal cyst nematode, spot form of net blotch, and leaf scald resistance, and are readily useable for marker-assisted barley breeding. The new maps are available on-line at www.genica.net.au.

Genome ◽  
2011 ◽  
Vol 54 (12) ◽  
pp. 1016-1028 ◽  
Author(s):  
Amaresh Chandra ◽  
K.K. Tiwari ◽  
D. Nagaich ◽  
N. Dubey ◽  
S. Kumar ◽  
...  

A limited number of functional molecular markers has slowed the desired genetic improvement of Stylosanthes species. Hence, in an attempt to develop simple sequence repeat (SSR) markers, genomic libraries from Stylosanthes seabrana B.L. Maass & ’t Mannetje (2n = 2x = 20) using 5′ anchored degenerate microsatellite primers were constructed. Of the 76 new microsatellites, 21 functional primer pairs were designed. Because of the small number of primer pairs designed, 428 expressed sequence tag (EST) sequences from seven Stylosanthes species were also examined for SSR detection. Approximately 10% of sequences delivered functional primer pairs, and after redundancy elimination, 57 microsatellite repeats were selected. Tetranucleotides followed by trinucleotides were the major repeated sequences in Stylosanthes ESTs. In total, a robust set of 21 genomic–SSR (gSSR) and 20 EST–SSR (eSSR) markers were developed. These markers were analyzed for intraspecific diversity within 20 S. seabrana accessions and for their cross-species transferability. Mean expected (He) and observed (Ho) heterozygosity values with gSSR markers were 0.64 and 0.372, respectively, whereas with eSSR markers these were 0.297 and 0.214, respectively. Dendrograms having moderate bootstrap value (23%–94%) were able to distinguish all accessions of S. seabrana with gSSR markers, whereas eSSR markers showed 100% similarities between few accessions. The set of 21 gSSRs, from S. seabrana, and 20 eSSRs, from selected Stylosanthes species, with their high cross-species transferability (45% with gSSRs, 86% with eSSRs) will facilitate genetic improvement of Stylosanthes species globally.


AoB Plants ◽  
2020 ◽  
Vol 12 (6) ◽  
Author(s):  
Morad M Mokhtar ◽  
Ebtissam H A Hussein ◽  
Salah El-Din S El-Assal ◽  
Mohamed A M Atia

Abstract Faba bean (Vicia faba) is an essential food and fodder legume crop worldwide due to its high content of proteins and fibres. Molecular markers tools represent an invaluable tool for faba bean breeders towards rapid crop improvement. Although there have historically been few V. faba genome resources available, several transcriptomes and mitochondrial genome sequence data have been released. These data in addition to previously developed genetic linkage maps represent a great resource for developing functional markers and maps that can accelerate the faba bean breeding programmes. Here, we present the Vicia faba Omics database (VfODB) as a comprehensive database integrating germplasm information, expressed sequence tags (ESTs), expressed sequence tags-simple sequence repeats (EST-SSRs), and mitochondrial-simple sequence repeats (mtSSRs), microRNA-target markers and genetic maps in faba bean. In addition, KEGG pathway-based markers and functional maps are integrated as a novel class of annotation-based markers/maps. Collectively, we developed 31 536 EST markers, 9071 EST-SSR markers and 3023 microRNA-target markers based on V. faba RefTrans V2 mining. By mapping 7940 EST and 2282 EST-SSR markers against the KEGG pathways database we successfully developed 107 functional maps. Also, 40 mtSSR markers were developed based on mitochondrial genome mining. On the data curation level, we retrieved 3461 markers representing 12 types of markers (CAPS, EST, EST-SSR, Gene marker, INDEL, Isozyme, ISSR, RAPD, SCAR, RGA, SNP and SSR), which mapped across 18 V. faba genetic linkage maps. VfODB provides two user-friendly tools to identify, classify SSR motifs and in silico amplify their targets. VfODB can serve as a powerful database and helpful platform for faba bean research community as well as breeders interested in Genomics-Assisted Breeding.


Botany ◽  
2010 ◽  
Vol 88 (5) ◽  
pp. 537-543 ◽  
Author(s):  
Yong-Bi Fu ◽  
Gregory W. Peterson

One major challenge in genetic and evolutionary studies of wild flax species is the lack of informative molecular markers. A set of 100 informative expressed sequence tag-derived simple sequence repeat (EST-SSR) primer pairs developed in cultivated flax ( Linum usitatissimum L.) were characterized on 35 Linum accessions representing 17 Linum species for their transferability to other Linum species. Ninety-nine primer pairs displayed scorable polymorphisms across 35 Linum samples and generated 627 bands likely from 121 loci. About 50% of the detected bands occurred only in three or fewer samples. A total of 393 bands, likely from 116 loci, were detected by 97 primer pairs in Linum bienne Mill. samples, but only up to 60 bands, likely from up to 39 loci, were revealed by 6 to 37 primer pairs in the samples of the other 15 Linum species. The L. bienne samples displayed 23.7% more EST-SSR variation than the L. usitatissimum samples. These characterized EST-SSR markers should be useful for future genetic diversity and evolutionary studies of Linum species, particularly for the progenitor of cultivated flax.


2013 ◽  
Vol 138 (4) ◽  
pp. 290-296 ◽  
Author(s):  
Raúl De la Rosa ◽  
Angjelina Belaj ◽  
Antonio Muñoz-Mérida ◽  
Oswaldo Trelles ◽  
Inmaculada Ortíz-Martín ◽  
...  

In the present work, a set of eight new hexa-nucleotide simple sequence repeats (SSRs) is reported in olive (Olea europaea L). These SSRs loci were generated on the basis of expressed sequence tag (EST) sequences in the frame of an olive genomic project. The markers showed a high level of polymorphism when tested on a set of cultivars used as genitors in the olive breeding program of Córdoba, Spain. The long-core repeat motif of these markers allows a wider separation among alleles, thus permitting an accurate genotyping. Besides, these markers showed comparable levels of polymorphism to di-nucleotide SSRs, the only ones so far reported in olive. Selected on the basis of their discrimination capacity, four of the eight SSRs were used to test their ability for paternity testing in a total of 81 seedlings coming from 12 crosses. The paternity testing showed that seven crosses matched the alleged paternity and the remaining five were products of illicit pollinations. These results exactly matched with previous paternity testing performed with di-nucleotide SSR markers. These results demonstrate the usefulness of the developed hexa-nucleotide repeated motifs for checking the paternity of breeding progenies and suggest their use on variability studies.


Author(s):  
Romeo Di Pietro ◽  
Antonio Luca Conte ◽  
Piera Di Marzio ◽  
Paola Fortini ◽  
Emmanuele Farris ◽  
...  

AbstractMolecular diversity analysis of deciduous pubescent oaks was conducted for populations from Calabria, Sicily and Sardinia. The aims of this study were twofold. First, to provide data on the genetic diversity of pubescent oaks from an understudied area which currently exhibits one of the highest concentrations of pubescent oak species in Europe. Second, to verify if these groups of oaks are genetically distinct and if their identification is in accordance with the current taxonomic classification. Molecular analyses of leaf material of 480 trees from seventeen populations belonging to putatively different pubescent oak species (Quercus amplifolia, Q. congesta, Q. dalechampii, Q. ichnusae, Q. leptobalanos, Q. virgiliana) were performed. Twelve gene-based Expressed Sequence Tag-Simple Sequence Repeat markers were selected, and genetic diversity and differentiation were calculated. The results showed relatively high values of allelic richness, heterozygosity and number of private alleles for the populations investigated. A weak but positive correlation between geographical and genetic distance was detected. Genetic assignment (STRUCTURE) and principle coordinate analyses exhibited a weak separation into two genetic groups which, however, did not correspond to the taxonomic, chorological and ecological features of the populations investigated. Sardinian populations formed one group which was separated from the Calabrian and Sicilian populations. In light of the results obtained, the taxonomic classification for the pubescent white oaks currently reported in the major Italian floras and checklists for the study area was not confirmed by molecular analyses.


2021 ◽  
Vol 12 ◽  
Author(s):  
Haftom Brhane ◽  
Teklehaimanot Haileselassie ◽  
Kassahun Tesfaye ◽  
Cecilia Hammenhag ◽  
Rodomiro Ortiz ◽  
...  

Finger millet (Eleusine coracana (L.) Geartn.) is a self-pollinating amphidiploid crop cultivated with minimal input for food and feed, as well as a source of income for small-scale farmers. To efficiently assess its genetic diversity for conservation and use in breeding programs, polymorphic DNA markers that represent its complex tetraploid genome have to be developed and used. In this study, 13 new expressed sequence tag-derived simple sequence repeat (EST-SSR) markers were developed based on publicly available finger millet ESTs. Using 10 polymorphic SSR markers (3 genomic and 7 novel EST-derived), the genetic diversity of 55 landrace accessions and 5 cultivars of finger millet representing its major growing areas in Ethiopia was assessed. In total, 26 alleles were detected across the 10 loci, and the average observed number of alleles per locus was 5.6. The polymorphic information content (PIC) of the loci ranged from 0.045 (Elco-48) to 0.71 (UGEP-66). The level of genetic diversity did not differ much between the accessions with the mean gene diversity estimates ranging only from 0.44 (accession 216054) to 0.68 (accession 237443). Similarly, a narrow range of variation was recorded at the level of regional states ranging from 0.54 (Oromia) to 0.59 (Amhara and Tigray). Interestingly, the average gene diversity of the landrace accessions (0.57) was similar to that of the cultivars (0.58). The analysis of molecular variance (AMOVA) revealed significant genetic variation both within and among accessions. The variation among the accessions accounted for 18.8% of the total variation (FST = 0.19; P < 0.001). Similarly, significant genetic variation was obtained among the geographic regions, accounting for 6.9% of the total variation (P < 0.001). The results of the cluster, principal coordinate, and population structure analyses suggest a poor correlation between the genetic makeups of finger millet landrace populations and their geographic regions of origin, which in turn suggests strong gene flow between populations within and across geographic regions. This study contributed novel EST-SSR markers for their various applications, and those that were monomorphic should be tested in more diverse finger millet genetic resources.


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