scholarly journals Sequence Tagged Site Markers to Rsp1, Rsp2, and Rsp3 Genes for Resistance to Septoria Speckled Leaf Blotch in Barley

2007 ◽  
Vol 97 (2) ◽  
pp. 162-169 ◽  
Author(s):  
S. H. Lee ◽  
S. M. Neate

Five random amplified polymorphic DNA markers, two in coupling (OPAH5545C, and OPBA12314C) and three in repulsion phase (UBC285158R, OPC2441R, and OPB17451R), closely linked to Rsp genes conferring resistance to Septoria speckled leaf blotch (SSLB), were identified using bulked segregant analysis in three F2 populations, each containing a Rsp gene. These markers were converted into the sequence tagged site (STS) markers SUBC285, SOPC2, SOPAH5, and SOPBA12. Another STS marker (MWG938) linked to Rsp2 in coupling phase was also identified in an F2 population from the cross Robust/CIho 4780. The STS markers were tested on a set of 42 resistant and susceptible barley germplasm lines and 98 landraces. The expected sizes of marker fragments associated with each allele at Rsp loci were present in resistant or susceptible accessions. Efficiency of marker-assisted selection (MAS) for Rsp1, Rsp2, and Rsp3 using STS markers were evaluated in three F2–3 populations in the greenhouse and the field. Results of testing F2–3 progeny demonstrated that the accuracy of MAS was, with one exception, greater than 97% in the greenhouse and in two field locations (90% in the Osnabrock, ND trial for Rsp2). The STS markers closely linked to Rsp genes also identified the SSLB resistance corresponding to Rsp1, Rsp2, or Rsp3 in gene pyramiding F2 populations. The STS markers tightly linked to Rsp genes may be useful for M and for pyramiding with other genes in barley breeding for SSLB resistance.

Genome ◽  
1998 ◽  
Vol 41 (3) ◽  
pp. 440-444 ◽  
Author(s):  
K R Tiwari ◽  
G A Penner ◽  
T D Warkentin

Powdery mildew is a serious disease of pea caused by the obligate parasite Erysiphe pisi Syd. Random amplified polymorphic DNA (RAPD) analysis has emerged as a cost-effective and efficient marker system. The objective of this study was to identify RAPD markers for powdery mildew resistance gene er-1. The resistant cultivar Highlight (carrying er-1) and the susceptible cultivar Radley were crossed, and F3 plants were screened with Operon (OP) and University of British Columbia (UBC) primers, using bulked segregant analysis. A total of 416 primers were screened, of which amplicons of three Operon primers, OPO-18, OPE-16, and OPL-6, were found to be linked to er-1. OPO-181200 was linked in coupling (trans to er-1) and no recombinants were found. OPE-161600 (4 ± 2 cM) and OPL-61900 (2 ± 2 cM) were linked in repulsion (cis to er-1). The fragments OPO-181200 and OPE-161600 were sequenced and specific primers designed. The specific primer pair Sc-OPO-181200 will be useful in identifying homozygous resistant individuals in F2 and subsequent segregating generations. Sc-OPE-161600 will have greatest utility in selecting heterozygous BC\dn6 nF1 individuals in backcross breeding programs.Key words: bulked segregant analysis,Erysiphe pisi, pea, RAPD.


Genome ◽  
1997 ◽  
Vol 40 (2) ◽  
pp. 188-194 ◽  
Author(s):  
P. K. Subudhi ◽  
R. P. Borkakati ◽  
S. S. Virmani ◽  
N. Huang

The thermosensitive genetic male sterility (TGMS) system is considered to be a more efficient alternative to the cytoplasmic male sterility (CMS) system for hybrid rice. An F2 population from a cross between a TGMS mutant line (IR32364TGMS) and IR68 was used to map the TGMS gene tms3(t). Fertile and sterile bulks were constructed following the classification of F2 plants into true breeding sterile, fertile, and segregating fertile plants based on F3 family studies. From the survey of 389 arbitrary primers in bulked segregant analysis, four RAPD markers were identified in which three, OPF182600, OPB19750, and OPAA7550, were linked to tms3(t) in repulsion phase and one, OPAC3640, was linked to tms3(t) in coupling phase. The tms3(t) gene was flanked by OPF182600 and OPAC3640 on one side and by OPAA7550 and OPB19750 on the other side. All four markers were low-copy sequences and two of them (OPF182600 and OPAC3640) detected polymorphism when the markers were used to probe the genomic blots. Subsequently, OPAC3640 was mapped to the short arm of chromosome 6 using a mapping population available at IRRI. However, no RFLP markers from this region showed linkage to tms3(t) owing to the lack of polymorphism between the parents. All RAPD fragments were cloned and partially sequenced from both ends. Thus, PCR primers can be designed to develop PCR markers for marker-assisted breeding to facilitate the transfer of tms3(t) from one genetic background to another.Key words: bulked segregant analysis, gene tagging, marker-assisted selection, RAPD, TGMS.


2000 ◽  
Vol 90 (9) ◽  
pp. 1039-1042 ◽  
Author(s):  
G. M. Tabor ◽  
T. L. Kubisiak ◽  
N. B. Klopfenstein ◽  
R. B. Hall ◽  
H. S. McNabb McNabb

In the north central United States, leaf rust caused by Melampsora medusae is a major disease problem on Populus deltoides. In this study we identified molecular markers linked to a M. medusae resistance locus (Lrd1) that was segregating 1:1 within an intraspecific P. deltoides family (C9425DD). Previous field results were confirmed in the controlled environment of a growth chamber through an excised whole-leaf inoculation method. Using bulked segregant analysis we identified two random amplified polymorphic DNA (RAPD) markers (OPG10340 and OPZ191800) that are linked to Lrd1. Based on segregation in a total of 116 progeny, the genetic distances between OPG10340 and OPZ191800 and the resistance locus were estimated as 2.6 and 7.4 Haldane centimorgans (cM), respectively. Multipoint linkage analyses strongly suggest the most likely order for these loci is Lrd1, OPG10340, and OPZ191800. These markers may prove to be instrumental in the eventual cloning of Lrd1, as well as for marker-assisted selection of leaf-rust resistant genotypes.


2002 ◽  
Vol 121 (6) ◽  
pp. 512-516 ◽  
Author(s):  
T. J. Frew ◽  
A. C. Russell ◽  
G. M. Timmerman-Vaughan

Genetics ◽  
1995 ◽  
Vol 141 (2) ◽  
pp. 503-512 ◽  
Author(s):  
H S Judelson ◽  
L J Spielman ◽  
R C Shattock

Abstract DNA markers linked to the determinants of mating type in the oomycete, Phytophthora infestans, were identified and used to address the genetic basis of heterothallism in the normally diploid fungus. Thirteen loci linked to the A1 and A2 mating types were initially identified by bulked segregant analysis using random amplified polymorphic DNA markers (RAPDs) and subsequently scored in three crosses polymorphisms (SSCP), cleaved amplified polymorphisms (CAPS), or allele-specific polymerase chain reaction markers (AS-PCR). All DNA markers mapped to a single region, consistent with a single locus determining both mating types. Long-range restriction mapping also demonstrated the linkage of the markers to one region and delimited the mating type locus to a 100-kb region. The interval containing the mating type locus displayed non-Mendelian segregation as only two of the four expected genotypes were detected in progeny. This is consistent with a system of balance lethal loci near the mating type locus. A model for mating type determination is presented in which the balanced lethals exclude form progeny those with potentially conflicting combinations of mating type alleles, such as those simultaneously expressing A1 and A2 functions.


2008 ◽  
Vol 59 (1) ◽  
pp. 62 ◽  
Author(s):  
Natalia Gutierrez ◽  
C. M. Avila ◽  
M. T. Moreno ◽  
A. M. Torres

Faba beans (Vicia faba L.) have a great potential as a protein-rich fodder crop, but anti-nutritional factors such as condensed tannins reduce the biological value of their protein. Tannins can be removed from seeds by any of the two complementary genes, zt-1 and zt-2, which also determine white-flowered plants. The less common gene, zt-2, is also associated with increased protein levels and energy values and reduced fibre content of the seeds. To identify a cost-effective marker linked to zt-2, we analysed a segregating F2 population derived from the cross between the coloured flower and high tannin content genotype Vf6 and a zt-2 line. By using Bulked Segregant Analysis (BSA), five RAPD markers linked in coupling and repulsion phase to zt-2 were identified and their conversion into Sequence Characterised Amplified Regions (SCARs) was attempted. Amplification of the SCARS was more consistent, although the initial polymorphism was lost. Restriction digestion of SCAR SCAD16589 with AluI (SCAD16-A), Bsp120I (SCAD16-B) and HinfI (SCAD16-H) revealed clear differences due to the amplification of different loci. The consensus sequence of these CAPs (Cleavage Amplification Polymorphisms) markers allowed discrimination of three bands from which two new forward SCAR primers were developed based on specific sequences from zero tannin and high tannin content genotypes. To improve the efficiency of the marker screening, a multiplex PCR was developed that allowed the simultaneous amplification of the SCAR with the same advantages as a codominant marker. Marker validation was carried out with a new F2 population segregating for flower colour and tannin content, underscoring the potential of these markers in breeding selection to introgress the zt-2 gene for the development of new tannin free faba bean cultivars.


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