scholarly journals New Simple Sequence Repeat Markers on Linkage Groups 2 and 7, and Investigation of New Sources of Eastern Filbert Blight Resistance in Hazelnut

2021 ◽  
pp. 1-18
Author(s):  
Merve Şekerli ◽  
Golnaz Komaei Koma ◽  
Jacob W. Snelling ◽  
Shawn A. Mehlenbacher
Keyword(s):  
Ssr Markers ◽  
Simple Sequence Repeat ◽  
The Other ◽  
Single Locus ◽  
Null Alleles ◽  
Dominant Allele ◽  
Sequence Repeat ◽  
Sources Of Resistance ◽  
Eastern Filbert Blight ◽  
Simple Sequence

Eastern filbert blight (EFB), caused by Anisogramma anomala, is a fungal disease threatening the european hazelnut (Corylus avellana) industry in the Willamette Valley of Oregon. The pathogen is endemic to the eastern United States where it causes little damage to the wild Corylus americana but causes severe cankers on most cultivars of the commercially important european hazelnut. The host genetic resistance in ‘Gasaway’ is conferred by a dominant allele at a single locus on linkage group 6 (LG6), and resistance from several other sources has been mapped to the same region. Some fungal isolates can overcome ‘Gasaway’ resistance, prompting a search for other sources of resistance. Resistance from other sources has been mapped to LG2 and LG7, for which additional simple sequence repeat (SSR) markers would facilitate marker-assisted selection (MAS). In this study, an in silico approach was used to develop new polymorphic SSR markers in the EFB resistance regions on LG2 and LG7. Starting with a search of 17 contigs of the ‘Jefferson’ genome sequence, 45 new polymorphic SSR markers were developed, characterized, and placed on the linkage map. The new SSR markers had an average of 10.18 alleles per locus, and average values for expected heterozygosity, observed heterozygosity, polymorphism information content, and frequency of null alleles of 0.72, 0.65, 0.68, and 0.068, respectively. Of the 42 new polymorphic SSRs segregating in the mapping population, 24 were on LG2, 12 were on LG7, and six were placed on other LGs. The new and previously developed SSR markers were used to study six new sources of EFB resistance, four from Russia and two from Crimea. Six resistant selections were crossed with susceptible selections, resulting in 7 progenies. Phenotyping for disease response revealed that segregation in progenies of the two Moscow selections (#2 and #27), one Russian selection (OSU 1187.101), and one Crimean selection (H3R12P62) fit the 1:1 segregation ratio expected for control of resistance by a dominant allele at a single locus; but in progenies of the other Russian selection (OSU 1166.123) and the other Crimean selection (H3R07P11), there was an excess of resistant seedlings. Correlation of disease scores and alleles at SSR loci indicated that resistance from three Russian selections (Moscow selections #2 and #27 and OSU 1166.123) and the Crimean selection H3R12P62 was on LG7, while resistance from Russian selection OSU 1187.101 was on LG2. Resistance from Crimean selection H3R07P11 was not correlated with markers on LG6, or LG2, or LG7. These sources and new SSR markers will be useful in MAS and the pyramiding of resistance genes in the breeding of new EFB-resistant cultivars.

scholarly journals Discovery, Characterization, and Linkage Mapping of Simple Sequence Repeat Markers In Hazelnut

2018 ◽  
Vol 143 (5) ◽  
pp. 347-362 ◽  
Author(s):  
Gehendra Bhattarai ◽  
Shawn A. Mehlenbacher
Keyword(s):  
Genetic Diversity ◽  
Linkage Map ◽  
Ssr Markers ◽  
Genome Sequence ◽  
Simple Sequence Repeat ◽  
Genomic Sequence ◽  
Geographic Origin ◽  
Null Alleles ◽  
Sequence Repeat ◽  
Simple Sequence

From the genome sequence of hazelnut (Corylus avellana), 192 new polymorphic simple sequence repeat (SSR) markers were developed, characterized, and used to investigate genetic diversity in 50 accessions. Next-generation sequencing allows inexpensive sequencing of plant genomes and transcriptomes, and efficient development of polymorphic SSR markers, also known as microsatellite markers, at low cost. A search of the genome sequence of ‘Jefferson’ hazelnut identified 9094 fragments with long repeat motifs of 4, 5, or 6 base pairs (bp), from which polymorphic SSR markers were developed. The repeat regions in the ‘Jefferson’ genome were used as references to which genomic sequence reads of seven additional cultivars were aligned in silico. Visual inspection for variation in repeat number among the aligned reads identified 246 as polymorphic, for which primer pairs were designed. Polymerase chain reaction (PCR) amplification followed by agarose gel separation indicated polymorphism at 195 loci, for which fluorescent forward primers were used to amplify the DNA of 50 hazelnut accessions. Amplicons were post-PCR multiplexed for capillary electrophoresis, and allele sizes were determined for 50 accessions. After eliminating three, 192 were confirmed as polymorphic, and 169 showed only one or two alleles in each of the 50 cultivars, as expected in a diploid. At these 169 SSRs, a total of 843 alleles were found, for an average of 4.99 and a range of 2 to 17 alleles per locus. The mean observed heterozygosity, expected heterozygosity, polymorphism information content, and the frequency of null alleles were 0.51, 0.53, 0.47, and 0.03, respectively. An additional 25 primer pairs produced more than two bands in some accessions with an average of 6.8 alleles. The UPGMA dendrogram revealed a wide genetic diversity and clustered the 50 accessions according to their geographic origin. Of the new SSRs, 132 loci were placed on the linkage map. These new markers will be useful for diversity and parentage studies, cultivar fingerprinting, marker-assisted selection, and aligning the linkage map with scaffolds of the genome sequence.

scholarly journals New Sources of Eastern Filbert Blight Resistance and Simple Sequence Repeat Markers on Linkage Group 6 in Hazelnut (Corylus avellana L.)

2021 ◽  
Vol 12 ◽  
Author(s):  
Golnaz Komaei Koma ◽  
Merve Şekerli ◽  
Jacob W. Snelling ◽  
Shawn A. Mehlenbacher
Keyword(s):  
Linkage Group ◽  
Ssr Markers ◽  
Simple Sequence Repeat ◽  
Corylus Avellana ◽  
Sequence Repeat ◽  
Disease Response ◽  
Resistance Sources ◽  
Group 6 ◽  
Eastern Filbert Blight ◽  
Simple Sequence

Commercial production of hazelnut (Corylus avellana) in Oregon’s Willamette Valley is threatened by eastern filbert blight (EFB), a serious canker disease caused by the pyrenomycete Anisogramma anomala (Peck) E. Müller. The fungus also prevents the establishment of hazelnut orchards in eastern North America. Genetic resistance is considered the most effective way to control the disease. A high level of EFB resistance was first discovered in ’Gasaway’. This resistance is conferred by a dominant allele at a single locus on linkage group 6 (LG6). Resistance from several additional sources has been assigned to the same chromosomal region. In this study, new simple sequence repeat (SSR) markers were developed for the resistance region on LG6 and new sources of resistance were investigated. Forty-two new SSR markers were developed from four contigs in the genome sequence of ‘Jefferson’ hazelnut, characterized, and nine of them were placed on LG6 of the genetic map. Accessions representing 12 new sources of EFB resistance were crossed with susceptible selections resulting in 18 seedling populations. Segregation ratios in the seedling populations fit the expected 1:1 ratio for 10 sources, while one source showed an excess of resistant seedlings and another showed an excess of susceptible seedlings. Based on correlation of disease response and scores of SSR markers in the ‘Gasaway’ resistance region in the seedlings, eight resistance sources were assigned to LG6. Linkage maps were constructed for each progeny using SSR markers. The LG6 resistance sources include two selections (#23 and #26) from the Russian Research Institute of Forestry and Mechanization near Moscow, four selections from southern Russia, one selection (OSU 1185.126) from Crimea, one selection (OSU 533.129) from Michigan, Corylus heterophylla ‘Ogyoo’ from the South Korea, and the interspecific hybrid ’Estrella #1’. These new LG6 resistance sources and SSR markers should be useful in breeding new cultivars, including the pyramiding of resistance genes. For the other four resistance sources (Moscow #37, hybrid selection OSU 401.014, C. americana ‘Winkler’ and C. americana OSU 366.060), SSR marker scores on linkage groups 6, 7 and 2 were not correlated with disease response and merit further investigation.

scholarly journals Genotyping of Peach and Nectarine Cultivars with SSR and SRAP Molecular Markers

2004 ◽  
Vol 129 (2) ◽  
pp. 204-210 ◽  
Author(s):  
Riaz Ahmad ◽  
Dan Potter ◽  
Stephen M. Southwick
Keyword(s):  
Molecular Markers ◽  
Ssr Markers ◽  
Simple Sequence Repeat ◽  
Sweet Cherry ◽  
Prunus Persica ◽  
Sequence Repeat ◽  
Srap Markers ◽  
Upgma Cluster Analysis ◽  
Commercially Important ◽  
Simple Sequence

Simple sequence repeat (SSR) and sequence related amplified polymorphism (SRAP) molecular markers were evaluated for detecting intraspecific variation in 38 commercially important peach and nectarine (Prunus persica) cultivars. Out of the 20 SSR primer pairs 17 were previously developed in sweet cherry and three in peach. The number of putative alleles revealed by SSR primer pairs ranged from one to five showing a low level of genetic variability among these cultivars. The average number of alleles per locus was 2.2. About 76% of cherry primers produced amplification products in peach and nectarine, showing a congeneric relationship within Prunus species. Only nine cultivars out of the 38 cultivars could be uniquely identified by the SSR markers. For SRAP, the number of fragments produced was highly variable, ranging from 10 to 33 with an average of 21.8 per primer combination. Ten primer combinations resulted in 49 polymorphic fragments in this closely related set of peaches and nectarines. Thirty out of the 38 peach and nectarine cultivars were identified by unique SRAP fingerprints. UPGMA Cluster analysis based on the SSR and SRAP polymorphic fragments was performed; the relationships inferred are discussed with reference to the pomological characteristics and pedigree of these cultivars. The results indicated that SSR and SRAP markers can be used to distinguish the genetically very close peach and nectarine cultivars as a complement to traditional pomological studies. However, for fingerprinting, SRAP markers appear to be much more effective, quicker and less expensive to develop than are SSR markers.

scholarly journals Assessment of the Genetic Diversity of Rice Germplasms Characterized by Black-Purple and Red Pericarp Color Using Simple Sequence Repeat Markers

Plants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 471
Author(s):  
Jae-Ryoung Park ◽  
Won-Tae Yang ◽  
Yong-Sham Kwon ◽  
Hyeon-Nam Kim ◽  
Kyung-Min Kim ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Ssr Markers ◽  
Simple Sequence Repeat ◽  
Germplasm Collection ◽  
Group Method ◽  
Sequence Repeat ◽  
Rice Varieties ◽  
Red Pericarp ◽  
Simple Sequence ◽  
Colored Rice

The assessment of the genetic diversity within germplasm collections can be accomplished using simple sequence repeat (SSR) markers and association mapping techniques. The present study was conducted to evaluate the genetic diversity of a colored rice germplasm collection containing 376 black-purple rice samples and 172 red pericarp samples, conserved by Dong-A University. There were 600 pairs of SSR primers screened against 11 rice varieties. Sixteen informative primer pairs were selected, having high polymorphism information content (PIC) values, which were then used to assess the genetic diversity within the collection. A total of 409 polymorphic amplified fragments were obtained using the 16 SSR markers. The number of alleles per locus ranged from 11 to 47, with an average of 25.6. The average PIC value was 0.913, ranging from 0.855 to 0.964. Four hundred and nine SSR loci were used to calculate Jaccard’s distance coefficients, using the unweighted pair-group method with arithmetic mean cluster analysis. These accessions were separated into several distinctive groups corresponding to their morphology. The results provided valuable information for the colored rice breeding program and showed the importance of protecting germplasm resources and the molecular markers that can be derived from them.

scholarly journals Grass Hosts Harbor More Diverse Isolates of Puccinia striiformis Than Cereal Crops

2016 ◽  
Vol 106 (4) ◽  
pp. 362-371 ◽  
Author(s):  
P. Cheng ◽  
X. M. Chen ◽  
D. R. See
Keyword(s):  
Ssr Markers ◽  
Stripe Rust ◽  
Simple Sequence Repeat ◽  
Puccinia Striiformis ◽  
The United States ◽  
Grass Species ◽  
Cereal Crops ◽  
Sequence Repeat ◽  
Grass Hosts ◽  
Simple Sequence

Puccinia striiformis causes stripe rust on cereal crops and many grass species. However, it is not clear whether the stripe rust populations on grasses are able to infect cereal crops and how closely they are related to each other. In this study, 103 isolates collected from wheat, barley, triticale, rye, and grasses in the United States were characterized by virulence tests and simple sequence repeat (SSR) markers. Of 69 pathotypes identified, 41 were virulent on some differentials of wheat only, 10 were virulent on some differentials of barley only, and 18 were virulent on some differentials of both wheat and barley. These pathotypes were clustered into three groups: group one containing isolates from wheat, triticale, rye, and grasses; group two isolates were from barley and grasses; and group three isolates were from grasses and wheat. SSR markers identified 44 multilocus genotypes (MLGs) and clustered them into three major molecular groups (MG) with MLGs in MG3 further classified into three subgroups. Isolates from cereal crops were present in one or more of the major or subgroups, but not all, whereas grass isolates were present in all of the major and subgroups. The results indicate that grasses harbor more diverse isolates of P. striiformis than the cereals.

scholarly journals Use of simple sequence repeat (SSR) markers for screening blue disease resistance in cotton germplasm exchange

2015 ◽  
Vol 14 (41) ◽  
pp. 2871-2875 ◽  
Author(s):  
Faustine Christopher ◽  
Vieira Hoffmann Lucia ◽  
Ismail Tibazarwa Flora ◽  
Lukonge Everina
Keyword(s):  
Disease Resistance ◽  
Ssr Markers ◽  
Simple Sequence Repeat ◽  
Sequence Repeat ◽  
Germplasm Exchange ◽  
Simple Sequence

scholarly journals ANALISIS KERAGAMAN GENETIK PLASMA NUTFAH KAKAO (Theobroma cacaoL.) BERDASARKANMARKA SSR / Analysis of Genetic Variability Germplasm of Cacao (Theobroma cacaoL.)Basedon SSR Marker

2020 ◽  
Vol 17 (4) ◽  
pp. 156
Author(s):  
Surti Kurniasih ◽  
Rubiyo Rubiyo ◽  
Asep Setiawan ◽  
Agus Purwantara ◽  
Sudarsono Sudarsono
Keyword(s):  
Genetic Diversity ◽  
Genetic Distance ◽  
Ssr Markers ◽  
Theobroma Cacao ◽  
Simple Sequence Repeat ◽  
Ssr Marker ◽  
Gene Diversity ◽  
Sequence Repeat ◽  
Theobroma Cacao L ◽  
Simple Sequence

<p>Microsatellite or simple sequence repeat (SSR) markers have proven to be an excellent tool for cultivar identification, pedigree analysis, and genetic distance evaluations among organisms. The objectives of this research were to characterize cacao collection of Indonesian Coffee and Cacao Research Institute (ICCRI) and to analyze their genetic diversity using SSR markers. In this research, 39 SSR primer pairs were used to amplify genomic DNA of 29 cacao clones. Amplified SSR fragments for each primer pair were scored as individual band and used to determine genetic distance among evaluated cacao clones. Results of the experiment indicated that all SSR primer pairs evaluated were able to produce SSR markers for 29 cacao clones. The results also indicated that 34 out of 39 microsatellite loci evaluated were polymorphic, while 5 others were monomorphic. The total number of observed alleles among 29 clones was 132. Number of alleles per locus ranged from 4-8, with an average of 5.5 alelles per locus. Results of data analysis indicated that the PIC value was 0.665, the observed heterozigosity (Ho) was 0.651, and the gene diversity (He) was 0.720. The PIC, Ho, and He values were considered high. Genetic distances were evaluated using NTSys version 2.1 and dendrogram was constructed. Results of analysis indicated that 12 cacao clones evaluated were clustered in the first group with diversity coefficient of &lt; 3.75. Nine cacao clones were in the second group but with the same value of diversity coefficient (&lt;7.50). The rest of the cacao clones were in the third group with diversity coefficient of&gt;7.50. Based on those finding, all SSR primer pairs evaluated could be used to analyze cacao genome and be useful for genetic diversity analysis of cacao germplasm. The SSR marker analysis in ICCRI cacao collections resulted in high PIC, high observed heterozygosity, and high genetic diversity.</p><p>Key words: Theobroma cacao L, microsatelite, molecular marker, genetic diversity, heterozygosity</p><p> </p><p><strong>Abstrak</strong></p><p>Marka mikrosatelit atau sekuens sederhana berulang (simple sequence repeat = SSR) terbukti merupakan alat yang bagus untuk identifikasi kultivar, analisis pedigree, dan evaluasi jarak genetik berbagai organisme. Penelitian ini bertujuan untuk:1) karakterisasi kakao koleksi Pusat penelitian Kopi dan Kakao Indonesia menggunakan marka SSR dan 2) analisis keragaman genetik klon-klon kakao koleksi dengan menggunakan marka SSR. Dalam penelitian ini, 39 pasangan primer SSR telah digunakan untuk amplifikasi DNA genomik dari 29 klon kakao. Skoring pita SSR hasil amplifikasi menggunakan masing-masing pasangan primer dilakukan secara terpisah dan digunakan untuk menentukan jarak genetik di antara klon kakao yang dievaluasi. Hasil percobaan menunjukkan bahwa semua pasangan primer SSR yang digunakan mampu menghasilkan pita DNA hasil amplifikasi (marka SSR) untuk 29 klon kakao yang diuji. Hasil penelitian juga menunjukkan bahwa 34 dari 39 lokus SSR yang dianalisis bersifat polimorfik sedangkan lima primer yang lain bersifat monomorfik. Dari 29 klon kakao yang dievaluasi, telah berhasil diamplifikasi sebanyak 132 alel, dengan kisaran antara 4-8 alel/lokus. Rataan jumlah alel per lokus sebanyak 5,50. Hasil analisis data yang dilakukan juga menunjukkan nilai PIC untuk marka SSR yang digunakan sebesar 0,665. Untuk populasi klon kakao yang dievaluasi, diperoleh nilai rataan heterosigositas pengamatan (Ho) sebesar 0,651 dan rataan diversitas gen (He) sebesar 0,720. Nilai PIC Ho dan He yang didapat tergolong tinggi. Berdasarkan analisis keragaman dengan menggunakan program NTSys, diperoleh hasil 12 klon kakao berada dalam grup pertama (koefisien keragaman&lt;3,75) dan9 klon berada dalam grup kedua, dengan koefisien keragaman &lt; 7,50. Sedangkan klon-klon lainnya mempunyai koefisien keragaman &gt; 7,50. Berdasarkan hasil penelitian dan analisis data disimpulkan bahwa marka SSR dapat digunakan untuk menganalisis keragaman genetik plasma nutfah kakao. Tingkat polimorfisme yang dihasilkan marka SSR relatif tinggi. Tingkat heterosigositas plasma nutfah kakao koleksi Puslit Kopi dan Kakao Indonesiarelatif tinggi, dan keragaman genetiknyacukup tinggi.</p><p>Kata kunci : Theobroma cacao L, mikrosatelit, marka molekuler, keragaman genetik, heterosigositas</p>

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