Saturation of two chromosome regions conferring resistance to SCMV with SSR and AFLP markers by targeted BSA

Abstract

Quantitative trait loci (QTLs) and bulked segregant analyses (BSA) identified the major genes Scmv1 on chromosome 6 and Scmv2 on chromosome 3, conferring resistance against sugarcane mosaic virus (SCMV) in maize. Both chromosome regions were further enriched for SSR and AFLP markers by targeted bulked segregant analysis (tBSA) in order to identify and map only markers closely linked to either Scmv1 or Scmv2. For identification of markers closely linked to the target genes, symptomless individuals of advanced backcross generations BC5 to BC9 were employed. All AFLP markers, identified by tBSA using 400 EcoRI/ MseI primer combinations, mapped within both targeted marker intervals. Fourteen SSR and six AFLP markers mapped to the Scmv1 region. Eleven SSR and 18 AFLP markers were located in the Scmv2 region. Whereas the linear order of SSR markers and the window size for the Scmv2 region fitted well with publicly available genetic maps, map distances and window size differed substantially for the Scmv1 region on chromosome 6. A possible explanation for the observed discrepancies is the presence of two closely linked resistance genes in the Scmv1 region.

Monosomic and molecular mapping of adult plant leaf rust resistance genes in the Brazilian wheat cultivar Toropi

“…The AFLP technique combines the strengths of different marker systems and provides opportunities for mapping plants with large genomes and low polymorphism rates, such as wheat. Recently, several studies have described the association of AFLP markers with important resistance genes, such as greenbug and Fusarium head blight resistance in wheat (Weng and Lazar, 2002;Guo et al, 2003), powdery mildew resistance in tomato (De Giovanni et al, 2004), and SCMV and RppQ resistance in corn (Dussle et al, 2003;Chen et al, 2004).…”

Targeted BSA mapping of Scmv1 and Scmv2 conferring resistance to SCMV using PstI/MseI compared with EcoRI/MseI AFLP markers

“…The plant materials of maize, Zea mays L., used in this study were the same as described by Dußle et al (2003): advanced backcross generations (BC i , i ¼ 5-9) from two parental lines, the SCMVresistant dent inbred FAP1360A (donor) and the highly susceptible flint inbred F7 (recurrent parent). The individuals were artificially inoculated with SCMV and the symptoms were recorded at weekly intervals.…”

“…AFLP markers were applied as described by Vos et al (1995) and modified by Dußle et al (2003). Genomic DNA was digested with two restriction enzymes PstI and MseI, and ligated to a PstI adapter (5¢-CTCGTAGACTGCGTA-CATGCA-3¢; 3¢-CATCTGACGCATGT-5¢) and a MseI adapter (5¢-GACGATGAGTCCTGAG-3¢; 3¢-TACTCAGGACTCAT-5¢).…”

“…For the effective identification of markers closely linked to SCMV resistance genes, Dußle et al (2003) applied a new targeted bulked segregant analysis (tBSA) to screen amplified fragment length polymorphism (AFLP) markers in a narrow genetic window surrounding the target genes. Six and eighteen EcoRI/MseI AFLP (Eco-AFLP) markers mapped to the Scmv1 and Scmv2 regions, respectively.…”

Challenges, Opportunities and Recent Advances in Sugarcane Breeding

“…Molecular markers have been useful to identify and map candidate genes in sugarcane breeding clones (Andru et al, 2011), from DNA regions (Tabasum et al, 2010) as well as from expressed RNA sequences (Wei et al, 2010). Bulked segregant analysis (BSA) coupled with molecular marker analysis of quantitative trait loci has been successful to develop genetic maps around resistance genes in sugarcane against diseases and pests (Asnaghi et al, 2004;Dussle et al, 2003). Molecular markers linked to yield were found in 27 regions of the sugarcane genome from a cross between the Australian variety Q165 and S. officinarum, whereas no significant correlations between stalk traits and sugar yield was found in the population analyzed (Aitken et al, 2008).…”