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Molecular characterization of a major gene -rich region in wheat (Triticum aestivum L.)

Devinder Sandhu, University of Nebraska - Lincoln

Abstract

Wheat belongs to tribe Triticeae of family Poaceae. Gene synteny is highly conserved among species of Triticeae and moderately among the Poaceae. The short arm of Triticeae homoeologous group 1 chromosomes is known to contain many agronomically important genes. Most of these useful genes are present in a major gene-rich region (‘1S0.8 region’) present on the short arm. The region spans ∼6% of the 1BS chromosome and is flanked by the breakpoints of deletions 1BS-4 and 1BS-19. The objectives of this study were to construct a fine physical map of homoeologous group 1 chromosomes in wheat, identify useful genes present in ‘1S0.8 region’, enrich this region with markers, and to study distribution of genes and recombination. High density fine physical map was generated using 121 RFLP markers on 51 single break deletion lines and was compared with a consensus genetic map of Triticeae and a genetic linkage map of Triticum tauschii. More than 90% of the group 1 markers were present in eight gene-rich regions encompassing ∼14% of the chromosome. Recombination occurs preferably in the gene-rich regions, and also is a function of distance from the centromere. For the enrichment of ‘1S0.8 region’ with markers RNAF/DD and comparative mapping approaches were used. For RNAF/DD, mRNA of two deletion lines flanking ‘1S0.8 region’ were amplified and size separated on a denaturing-polyacrylamide-urea gel. Sixty-five fragment bands, which were present in IBS-4 but missing in IBS-19 were tested by gel blot DNA analysis of group 1 nullisomic tetrasomic lines and the two deletion lines. Of these 65 fragments, 19 detected smear pattern. Twenty-two of the 46 usable probes, mapped to group 1 and seven mapped to the ‘1S0.8 region’. For comparative mapping thirty-five different maps from Poaceae were compared and 75 agronomically important genes along with 93 potential DNA markers were identified for ‘1S0.8 region’. Seventy-three of the 93 probes mapped to group 1 and detected 91 loci. Fifty-two marker loci mapped to ‘1S0.8 region’ and 13 to ‘1S0.5 region’. ^

Subject Area

Agriculture, Agronomy|Biology, Molecular|Biology, Genetics

Recommended Citation

Sandhu, Devinder, "Molecular characterization of a major gene -rich region in wheat (Triticum aestivum L.)" (2000). ETD collection for University of Nebraska - Lincoln. AAI3027467.
http://digitalcommons.unl.edu/dissertations/AAI3027467

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