Transferability of cereal EST-SSR markers to ryegrass

Genome ◽  
2009 ◽  
Vol 52 (5) ◽  
pp. 431-437 ◽  
Author(s):  
Sung-Chur Sim ◽  
Ju-Kyung Yu ◽  
Young-ki Jo ◽  
Mark E. Sorrells ◽  
Geunhwa Jung

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 cereal EST-SSRs in ryegrass ( Lolium spp.). A total of 165 cereal EST-SSRs were tested; a high rate of transferability (57%) and polymorphism (67% of functional EST-SSRs) was demonstrated between cereals and ryegrass. A total of 46 segregating loci derived from 37 EST-SSRs were mapped on an existing ryegrass genetic map. The mapped loci were uniformly distributed across all seven linkage groups without significant clustering at the distal regions of linkage groups. Sequences of ryegrass amplicons generated by randomly selected 16 EST-SSRs were aligned with reference sequences of cereal EST-SSRs. The SSR motifs and repeat lengths of the cereal EST-SSR markers were different from the majority of ryegrass amplicons. Furthermore, a majority of EST-SSRs amplified different flanking sequences of SSRs in ryegrass than the original cereal sequences. Our results suggest that the high degree of cereal EST-SSR transferability to ryegrass can be a useful enhancement to the molecular database of PCR-based markers but sequence analysis is essential before transferring genetic information using comparative mapping.

2010 ◽  
Vol 135 (6) ◽  
pp. 511-520 ◽  
Author(s):  
Karen R. Harris-Shultz ◽  
Brian M. Schwartz ◽  
Wayne W. Hanna ◽  
Jeff A. Brady

Genetic linkage maps of bermudagrass (Cynodon spp.) species using 118 triploid individuals derived from a cross of T89 [C. dactylon (2n = 4x = 36)] and T574 [C. transvaalensis (2n = 2x = 18)] were enriched with expressed sequence tags-derived simple sequence repeat (EST-SSR) markers. Primers were developed from 53 ESTs containing SSRs producing 75 segregating markers from which 28 could be mapped to the T89 and T574 genetic maps. With the addition of previously generated marker data, 26 T89 linkage groups and eight T574 linkage groups were formed using a log-of-odds (LOD) value of 4.0. The T89 and T574 linkage maps spanned 1055 cM and 311.1 cM and include 125 and 36 single-dose amplified fragments (SDAFs), respectively. Many of the SDAFs displayed disomic segregation and thus T89 may be a segmental allotetraploid or an allotetraploid. The additional EST-SSR markers add value to the maps by increasing marker density and provide markers that can be easily transferred to other bermudagrass populations. Furthermore, EST-SSRs can be immediately used to assess genetic diversity, identify non-mutated cultivars of bermudagrass, confirm pedigrees, and differentiate contaminants from cultivars derived from ‘Tifgreen’.


Crustaceana ◽  
2019 ◽  
Vol 92 (7) ◽  
pp. 841-851
Author(s):  
Xuekai Han ◽  
Ruyi Xu ◽  
Yuyu Zheng ◽  
Meirong Gao ◽  
Liying Sui

Abstract Artemia is one of the most important live food items used in larviculture. In order to study the genetic diversity of Artemia in China, 170 novel simple sequence repeats (SSR) markers were identified from expressed sequence tags (ESTs) of the transcriptome library of Artemia parthenogenetica. Of these, 8 microsatellite loci were developed to characterize three geographical populations of Artemia. The results showed the expected and observed heterozygosity varied from 0.43 to 0.50 and from 0.59 to 0.64, respectively. The PIC (polymorphic information content) ranged from 0.37 to 0.45. These observations indicated that the Yuncheng population has the highest genetic diversity, whereas the Shuanghu population has the lowest. The Fst value (genetic differentiation coefficient) indicated that the three populations are highly differentiated. Genetic identity analyses revealed that the Yuncheng and Shuanghu populations have the closest relationship. The SSR markers described here will serve as a valuable tool for further studies in population and conservation genetics on Artemia.


2004 ◽  
Vol 109 (4) ◽  
pp. 800-805 ◽  
Author(s):  
N. Nicot ◽  
V. Chiquet ◽  
B. Gandon ◽  
L. Amilhat ◽  
F. Legeai ◽  
...  

HortScience ◽  
2016 ◽  
Vol 51 (3) ◽  
pp. 227-231 ◽  
Author(s):  
Wenting Wang ◽  
Chao Feng ◽  
Zehuang Zhang ◽  
Liju Yan ◽  
Maomao Ding ◽  
...  

Chinese bayberry (Morella rubra) is an economically important subtropical evergreen fruit crop native to China and other Asian countries. For facilitating cultivar discrimination and genetic diversity analysis, a total of 38 high-quality and highly polymorphic expressed sequence tags-simple sequence repeat (EST-SSR) markers, with little or no polymerase chain reaction (PCR) stutter bands, including 21 screened from those obtained previously and 17 newly developed markers, were developed. The average number of alleles (Na) per locus was 5.6, and polymorphism information content varied from 0.34 to 0.86, with a mean value of 0.57. With these markers, all 42 Chinese bayberry accessions analyzed were successfully discriminated and the phylogenetic relationship between accessions was revealed. The accessions can be separated into two groups with six subgroups. The grouping of four main cultivars in three subgroups and 12 white-fruited accessions, each with little or no anthocyanin accumulation in ripe fruit, into five subgroups suggested the preservation of broad diversity among cultivated populations. These EST-SSR markers and the findings obtained in this study can assist the discrimination of cultivars and lines and contribute to genetic and breeding studies in Chinese bayberry.


2007 ◽  
Vol 42 (3) ◽  
pp. 377-384 ◽  
Author(s):  
Fernanda de Oliveira Pinto ◽  
Mirian Perez Maluf ◽  
Oliveiro Guerreiro-Filho

The objective of this work was to identify expressed simple sequence repeats (SSR) markers associated to leaf miner resistance in coffee progenies. Identification of SSR markers was accomplished by directed searches on the Brazilian Coffee Expressed Sequence Tags (EST) database. Sequence analysis of 32 selected SSR loci showed that 65% repeats are of tetra-, 21% of tri- and 14% of dinucleotides. Also, expressed SSR are localized frequently in the 5'-UTR of gene transcript. Moreover, most of the genes containing SSR are associated with defense mechanisms. Polymorphisms were analyzed in progenies segregating for resistance to the leaf miner and corresponding to advanced generations of a Coffea arabica x Coffea racemosa hybrid. Frequency of SSR alleles was 2.1 per locus. However, no polymorphism associated with leaf miner resistance was identified. These results suggest that marker-assisted selection in coffee breeding should be performed on the initial cross, in which genetic variability is still significant.


2011 ◽  
Vol 102 (1) ◽  
pp. 113-122 ◽  
Author(s):  
S. Jing ◽  
B. Liu ◽  
L. Peng ◽  
X. Peng ◽  
L. Zhu ◽  
...  

AbstractTo assess genetic diversity in populations of the brown planthopper (Nilaparvata lugensStål) (Homoptera: Delphacidae), we have developed and applied microsatellite, or simple sequence repeat (SSR), markers from expressed sequence tags (ESTs). We found that the brown planthopper clusters of ESTs were rich in SSRs with unique frequencies and distributions of SSR motifs. Three hundred and fifty-one EST-SSR markers were developed and yielded clear bands from samples of four brown planthopper populations. High cross-species transferability of these markers was detected in the closely related planthopperN. muiri. The newly developed EST-SSR markers provided sufficient resolution to distinguish within and among biotypes. Analyses based on SSR data revealed host resistance-based genetic differentiation among different brown planthopper populations; the genetic diversity of populations feeding on susceptible rice varieties was lower than that of populations feeding on resistant rice varieties. This is the first large-scale development of brown planthopper SSR markers, which will be useful for future molecular genetics and genomics studies of this serious agricultural pest.


Genome ◽  
2003 ◽  
Vol 46 (2) ◽  
pp. 277-290 ◽  
Author(s):  
Eline van Zijll de Jong ◽  
Kathryn M Guthridge ◽  
German C Spangenberg ◽  
John W Forster

Fungal endophytes of the genus Neotyphodium are common in temperate pasture grass species and confer both beneficial and deleterious agronomic characteristics to their hosts. The aim of this study was to develop molecular markers based on simple sequence repeat (SSR) loci for the identification and assessment of genetic diversity among Neotyphodium endophytes in grasses. Expressed sequence tags (ESTs) from both Neptyphodium coenophialum and Neotyphodium lolii were examined, and unique SSR loci were identified in 9.7% of the N. coenophialum sequences and 6.3% of the N. lolii sequences. A variety of SSRs were present, although perfect trinucleotide repeat arrays were the most common. Primers were designed to 50 SSR loci from N. coenophialum and 57 SSR loci from N. lolii and were evaluated using 20 Neotyphodium and Epichloë isolates. A high proportion of the N. coenophialum and N. lolii primers produced amplification products from the majority of isolates and most of these primers detected genetic variation. SSR markers from both N. coenophialum and N. lolii detected high levels of polymorphism between Neotyphodium and Epichloë species, and low levels of polymorphism within N. coenophialum and N. lolii. SSR markers may be used in appropriate combinations to discriminate between species. Comparison with amplified fragment length polymorphism (AFLP) data demonstrated that the SSR markers were informative for the assessment of genetic variation within and between endophyte species. These markers may be used to identify endophyte taxa and to evaluate intraspecific population diversity, which may be correlated with variation for endophyte-derived agronomic traits.Key words: Neotyphodium, simple sequence repeats, expressed sequence tags, amplified fragment length polymorphism, genetic diversity.


2011 ◽  
Vol 60 (1-6) ◽  
pp. 161-163 ◽  
Author(s):  
X. Yang ◽  
X. Sun ◽  
S. Zhang

Abstract Six simple sequence repeats (SSR) markers were developed from expressed sequence tags (ESTs) in the genus Larix. Based on evaluation with 49 L. kaempferi genotypes, the number of alleles per locus ranged from two to four, and the expected (He) and observed (Ho) heterozygosity values were 0.225−0.694 and 0.201−0.656, respectively. The inbreeding coffcient (FIS) for all loci were less than zero except that LAReSSR85 was 0.4383. All the six EST-SSR markers were transferable to L. gmelini, L. olgensis var Koreana, L. principisrupprechtii and L. olgensis. BlastX analysis showed that five of the EST-SSRs were homologous to known genes. The six EST-SSR markers developed here can be valuable for biological applications in Larix.


Genome ◽  
2005 ◽  
Vol 48 (5) ◽  
pp. 811-822 ◽  
Author(s):  
Daniel J Mullan ◽  
Amanda Platteter ◽  
Natasha L Teakle ◽  
Rudi Appels ◽  
Timothy D Colmer ◽  
...  

Lophopyrum elongatum, a close relative of wheat, provides a source of novel genes for wheat improvement. Molecular markers were developed to monitor the introgression of L. elongatum chromosome segments into hexaploid wheat. Existing simple sequence repeats (SSRs) derived from genomic libraries were initially screened for detecting L. elongatum loci in wheat, but only 6 of the 163 markers tested were successful. To increase detection of L. elongatum specific loci, 165 SSRs were identified from wheat expressed sequence tags (ESTs), where their chromosomal positions in wheat were known from deletion bin mapping. Detailed sequence analysis identified 41 SSRs within this group as potentially superior in their ability to detect L. elongatum loci. BLASTN alignments were used to position primers within regions of the ESTs that have sequence conservation with at least 1 similar EST from another cereal species. The targeting of primers in this manner enabled 14 L. elongatum markers from 41 wheat ESTs to be identified, whereas only 2 from 124 primers designed in random positions flanking SSRs detected L. elongatum loci. Addition and ditelosomic lines were used to assign all 22 markers to specific chromosome locations in L. elongatum. Nine of these SSR markers were assigned to homoeologous chromosome locations based on their similar position in hexaploid wheat. The remaining markers mapped to other L. elongatum chromosomes indicating a degree of chromosome rearrangements, paralogous sequences and (or) sequence variation between the 2 species. The EST-SSR markers were also used to screen other wheatgrass species indicating further chromosome rearrangements and (or) sequence variation between wheatgrass genomes. This study details methodologies for the generation of SSRs for detecting L. elongatum loci.Key words: Lophopyrum elongatum, expressed sequence tags (EST), simple sequence repeat (SSR), EST-SSR, synteny, alien introgression.


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