scholarly journals Development of a genetic linkage map for Sharon goatgrass (Aegilops sharonensis) and mapping of a leaf rust resistance gene

Genome ◽  
2013 ◽  
Vol 56 (7) ◽  
pp. 367-376 ◽  
Author(s):  
P.D. Olivera ◽  
A. Kilian ◽  
P. Wenzl ◽  
B.J. Steffenson

Aegilops sharonensis (Sharon goatgrass), a diploid wheat relative, is known to be a rich source of disease resistance genes for wheat improvement. To facilitate the transfer of these genes into wheat, information on their chromosomal location is important. A genetic linkage map of Ae. sharonensis was constructed based on 179 F2 plants derived from a cross between accessions resistant (1644) and susceptible (1193) to wheat leaf rust. The linkage map was based on 389 markers (377 Diversity Arrays Technology (DArT) and 12 simple sequence repeat (SSR) loci) and was comprised of 10 linkage groups, ranging from 2.3 to 124.6 cM. The total genetic length of the map was 818.0 cM, with an average interval distance between markers of 3.63 cM. Based on the chromosomal location of 115 markers previously mapped in wheat, the four linkage groups of A, B, C, and E were assigned to Ae. sharonensis (Ssh) and homoeologous wheat chromosomes 6, 1, 3, and 2. The single dominant gene (designated LrAeSh1644) conferring resistance to leaf rust race THBJ in accession 1644 was positioned on linkage group A (chromosome 6Ssh) and was flanked by DArT markers wpt-9881 (at 1.9 cM distal from the gene) and wpt-6925 (4.5 cM proximal). This study clearly demonstrates the utility of DArT for genotyping uncharacterized species and tagging resistance genes where pertinent genomic information is lacking.

2021 ◽  
Vol 12 ◽  
Author(s):  
Qiang Zhang ◽  
Wenxin Wei ◽  
Xiangxi Zuansun ◽  
Shengnan Zhang ◽  
Chen Wang ◽  
...  

Wheat leaf rust (also known as brown rust), caused by the fungal pathogen Puccinia triticina Erikss. (Pt), is one by far the most troublesome wheat disease worldwide. The exploitation of resistance genes has long been considered as the most effective and sustainable method to control leaf rust in wheat production. Previously the leaf rust resistance gene Lr65 has been mapped to the distal end of chromosome arm 2AS linked to molecular marker Xbarc212. In this study, Lr65 was delimited to a 0.8 cM interval between flanking markers Alt-64 and AltID-11, by employing two larger segregating populations obtained from crosses of the resistant parent Altgold Rotkorn (ARK) with the susceptible parents Xuezao and Chinese Spring (CS), respectively. 24 individuals from 622 F2 plants of crosses between ARK and CS were obtained that showed the recombination between Lr65 gene and the flanking markers Alt-64 and AltID-11. With the aid of the CS reference genome sequence (IWGSC RefSeq v1.0), one SSR marker was developed between the interval matched to the Lr65-flanking marker and a high-resolution genetic linkage map was constructed. The Lr65 was finally located to a region corresponding to 60.11 Kb of the CS reference genome. The high-resolution genetic linkage map founded a solid foundation for the map-based cloning of Lr65 and the co-segregating marker will facilitate the marker-assisted selection (MAS) of the target gene.


2000 ◽  
Vol 66 (12) ◽  
pp. 5290-5300 ◽  
Author(s):  
Luis M. Larraya ◽  
G�mer P�rez ◽  
Enrique Ritter ◽  
Antonio G. Pisabarro ◽  
Lucı́a Ramı́rez

ABSTRACT We have constructed a genetic linkage map of the edible basidiomycete Pleurotus ostreatus (var. Florida). The map is based on the segregation of 178 random amplified polymorphic DNA and 23 restriction fragment length polymorphism markers; four hydrophobin, two laccase, and two manganese peroxidase genes; both mating type loci; one isozyme locus (est1); the rRNA gene sequence; and a repetitive DNA sequence in a population of 80 sibling monokaryons. The map identifies 11 linkage groups corresponding to the chromosomes ofP. ostreatus, and it has a total length of 1,000.7 centimorgans (cM) with an average of 35.1 kbp/cM. The map shows a high correlation (0.76) between physical and genetic chromosome sizes. The number of crossovers observed per chromosome per individual cell is 0.89. This map covers nearly the whole genome of P. ostreatus.


Genome ◽  
1999 ◽  
Vol 42 (4) ◽  
pp. 657-661 ◽  
Author(s):  
Y Yao ◽  
M Ban ◽  
J Brandle

To lay a foundation for molecular breeding efforts, the first genetic linkage map for Stevia rebaudiana has been constructed using segregation data from a pseudo test-cross F1 population. A total of 183 randomly amplified polymorphic DNA (RAPD) markers were analysed and assembled into 21 linkage groups covering a total distance of 1389 cM, with an average distance between markers of of 7.6 cM. The 11 largest linkage groups consisted of 4-19 loci, ranged in length from 56 to 174 cM, and accounted for 75% of the total map distance. Fifteen RAPD loci were found to be unlinked. From the 521 primers showing amplification products, 185 (35.5%) produced a total of 293 polymorphic fragments, indicating a high level of genetic diversity in stevia. Most of the RAPD markers in stevia segregated in normal Mendelian fashion.Key words: stevia, open-pollinated, genome map, RAPD.


2015 ◽  
Vol 154 (7) ◽  
pp. 1209-1217 ◽  
Author(s):  
A. BOONCHANAWIWAT ◽  
S. SRAPHET ◽  
S. WHANKAEW ◽  
O. BOONSENG ◽  
D. R. SMITH ◽  
...  

SUMMARYCassava (Manihot esculenta Crantz) is an economically important root crop in Thailand, which is ranked the world's top cassava exporting country. Production of cassava can be hampered by several pathogens and pests. Cassava anthracnose disease (CAD) is an important disease caused by the fungus Colletotrichum gloeosporioides f. sp. manihotis. The pathogen causes severe stem damage resulting in yield reductions and lack of stem cuttings available for planting. Molecular studies of cassava response to CAD will provide useful information for cassava breeders to develop new varieties with resistance to the disease. The current study aimed to identify quantitative trait loci (QTL) and DNA markers associated with resistance to CAD. A total of 200 lines of two F1 mapping populations were generated by reciprocal crosses between the varieties Huabong60 and Hanatee. The F1 samples were genotyped based on simple sequence repeat (SSR) and expressed sequence tag-SSR markers and a genetic linkage map was constructed using the JoinMap®/version3·0 program. The results showed that the map consisted of 512 marker loci distributed on 24 linkage groups with a map length of 1771·9 centimorgan (cM) and a mean interval between markers of 5·7 cM. The genetic linkage map was integrated with phenotypic data for the response to CAD infection generated by a detached leaf assay test. A total of three QTL underlying the trait were identified on three linkage groups using the MapQTL®/version4·0 program. Those DNA markers linked to the QTL that showed high statistically significant values with the CAD resistance trait were identified for gene annotation analysis and 23 candidate resistance genes to CAD infection were identified.


Genome ◽  
2012 ◽  
Vol 55 (5) ◽  
pp. 360-369 ◽  
Author(s):  
Wengang Xie ◽  
Joseph G. Robins ◽  
B. Shaun Bushman

Orchardgrass ( Dactylis glomerata L.), or cocksfoot, is indigenous to Eurasia and northern Africa, but has been naturalized on nearly every continent and is one of the top perennial forage grasses grown worldwide. To improve the understanding of genetic architecture of orchardgrass and provide a template for heading date candidate gene search in this species, the goals of the present study were to construct a tetraploid orchardgrass genetic linkage map and identify quantitative trait loci associated with heading date. A combination of SSR markers derived from an orchardgrass EST library and AFLP markers were used to genotype an F1 population of 284 individuals derived from a very late heading Dactylis glomerata subsp. himalayensis parent and an early to mid-heading Dactylis glomerata subsp. aschersoniana parent. Two parental maps were constructed with 28 cosegregation groups and seven consensus linkage groups each, and homologous linkage groups were tied together by 38 bridging markers. Linkage group lengths varied from 98 to 187 cM, with an average distance between markers of 5.5 cM. All but two mapped SSR markers had homologies to physically mapped rice (Oryza sativa L.) genes, and six of the seven orchardgrass linkage groups were assigned based on this putative synteny with rice. Quantitative trait loci were detected for heading date on linkage groups 2, 5, and 6 in both parental maps, explaining between 12% and 24% of the variation.


1999 ◽  
Vol 133 (4) ◽  
pp. 389-395 ◽  
Author(s):  
M. A. CHOWDHURY ◽  
A. E. SLINKARD

We constructed a genetic linkage map of grasspea (Lathyrus sativus L.; 2n = 14) from 100 F2 individuals derived from a cross between PI 426891.1.3 and PI 283564c.3.2. A total of 71 RAPD, three isozyme and one morphological markers segregated in the F2 progeny. A small fraction of markers (12%) deviated significantly from the expected Mendelian ratio (1[ratio ]2[ratio ]1 or 3[ratio ]1). Out of 75 markers, 69 (one morphological, three isozyme and 65 RAPD markers) were assigned to 14 linkage groups comprising 898 cM. The average distance between two adjacent markers was 17·2 cM. The present linkage map will serve as a reference point for further linkage studies in grasspea.


Genome ◽  
2011 ◽  
Vol 54 (10) ◽  
pp. 819-828 ◽  
Author(s):  
Ivan W. Mott ◽  
Steven R. Larson ◽  
Thomas A. Jones ◽  
Joseph G. Robins ◽  
Kevin B. Jensen ◽  
...  

Elymus L. is the largest and most complex genus in the Triticeae tribe of grasses with approximately 150 polyploid perennial species occurring worldwide. We report here the first genetic linkage map for Elymus. Backcross mapping populations were created by crossing caespitose Elymus wawawaiensis (EW) (Snake River wheatgrass) and rhizomatous Elymus lanceolatus (EL) (thickspike wheatgrass) to produce F1 interspecific hybrids that were then backcrossed to the same EL male to generate progeny with segregating phenotypes. EW and EL are both allotetraploid species (n = 14) containing the St (Pseudoroegneria) and H (Hordeum) genomes. A total of 387 backcross progeny from four populations were genotyped using 399 AFLP and 116 EST-based SSR and STS markers. The resulting consensus map was 2574 cM in length apportioned among the expected number of 14 linkage groups. EST-based SSR and STS markers with homology to rice genome sequences were used to identify Elymus linkage groups homoeologous to chromosomes 1–7 of wheat. The frequency of St-derived genome markers on each linkage group was used to assign genome designations to all linkage groups, resulting in the identification of the seven St and seven H linkage groups of Elymus. This map also confirms the alloploidy and disomic chromosome pairing and segregation of Elymus and will be useful in identifying QTLs controlling perennial grass traits in this genus.


2009 ◽  
Vol 18 (2) ◽  
pp. 165-172 ◽  
Author(s):  
Samiul Haque ◽  
Nadim Ashraf ◽  
Selina Begum ◽  
R.H. Sarkar ◽  
Haseena Khan

The first and preliminary genetic linkage map of the jute genome was constructed with RAPD markers using two parents (variety O-9897 and accession no. 1805) and their F2 populations. Linkage analysis at a LOD (Log of odds base 10) score of 3.0 and a maximum distance 50 cM revealed 18 linkage groups. Among the 18 linkage groups, 15 contained single locus and the remaining three groups 16, 17 and 18 contained 2, 11 and 12 loci, respectively. The three multi locus linkage groups varying in length from 15.9 - 241.7 cM, snapped a total length of 463.7 cM with an average marker density of 19.6 cM between adjacent markers. The basic chromosome number of Corchorus spp. is seven (2n = 14), so in saturated map, seven linkage groups should have been obtained to represent the genome. But for linkage group analysis, the effort was very limited and the total number of loci (40) was also low.  Key words: Jute, Linkage map, RAPD, Polymorphism D.O.I 10.3329/ptcb.v18i2.3647 Plant Tissue Cult. & Biotech. 18(2): 165-172, 2008 (December)


Genome ◽  
2012 ◽  
Vol 55 (6) ◽  
pp. 417-427 ◽  
Author(s):  
A. Gadaleta ◽  
A. Giancaspro ◽  
S.L. Giove ◽  
S. Zacheo ◽  
O. Incerti ◽  
...  

The aims of the present study were to provide deletion maps for wheat ( Triticum aestivum L.) chromosomes 5A and 5B and a detailed genetic map of chromosome 5A enriched with popular microsatellite markers, which could be compared with other existing maps and useful for mapping major genes and quantitative traits loci (QTL). Physical mapping of 165 gSSR and EST–SSR markers was conducted by amplifying each primer pair on Chinese Spring, aneuploid lines, and deletion lines for the homoeologous group 5 chromosomes. A recombinant inbred line (RIL) mapping population that is recombinant for only chromosome 5A was obtained by crossing the wheat cultivar Chinese Spring and the disomic substitution line Chinese Spring-5A dicoccoides and was used to develop a genetic linkage map of chromosome 5A. A total of 67 markers were found polymorphic between the parental lines and were mapped in the RIL population. Sixty-three loci and the Q gene were clustered in three linkage groups ordered at a minimum LOD score of 5, while four loci remained unlinked. The whole genetic 5A chromosome map covered 420.2 cM, distributed among three linkage groups of 189.3, 35.4, and 195.5 cM. The EST sequences located on chromosomes 5A and 5B were used for comparative analysis against Brachypodium distachyon (L.) P. Beauv. and rice ( Oryza sativa L.) genomes to resolve orthologous relationships among the genomes of wheat and the two model species.


Genome ◽  
2012 ◽  
Vol 55 (4) ◽  
pp. 327-335 ◽  
Author(s):  
Xiaoxia Yu ◽  
Xiaolei Li ◽  
Yanhong Ma ◽  
Zhuo Yu ◽  
Zaozhe Li

Using a population of 105 interspecific F2 hybrids derived from a cross between Agropyron mongolicum Keng and Agropyron cristatum (L.) Gaertn. ‘Fairway’ as a mapping population, a genetic linkage map of crested wheatgrass was constructed based on AFLP and RAPD molecular markers. A total of 175 markers, including 152 AFLP and 23 RAPD markers, were ordered in seven linkage groups. The map distance was 416 cM, with a mean distance of 2.47 cM between markers. The number of markers ranged from 13 to 46 in each linkage group and the length of groups ranged from 18 to 104 cM. The research found that 30 out of 175 molecular markers showed segregation distortion, accounting for 17% of all markers. This is the first genetic linkage map of crested wheatgrass. This map will facilitate gene localization, cloning, and molecular marker-assisted selection in the future.


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