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Radiation Hybrid Mapping of the Species Cytoplasm-Specific (scsae) Gene in Wheat

2004; Oxford University Press; Volume: 168; Issue: 1 Linguagem: Inglês

10.1534/genetics.103.022590

1943-2631

Khwaja Hossain, Oscar Riera‐Lizarazu, Venugopal Kalavacharla, M. Isabel Vales, S. S. Maan, Shahryar F. Kianian,

Genetic Mapping and Diversity in Plants and Animals

Radiation hybrid (RH) mapping is based on radiation-induced chromosome breakage and analysis of chromosome segment retention or loss using molecular markers. In durum wheat (Triticum turgidum L., AABB), an alloplasmic durum line [(lo) durum] has been identified with chromosome 1D of T. aestivum L. (AABBDD) carrying the species cytoplasm-specific (scsae) gene. The chromosome 1D of this line segregates as a whole without recombination, precluding the use of conventional genome mapping. A radiation hybrid mapping population was developed from a hemizygous (lo) scsae--line using 35 krad gamma rays. The analysis of 87 individuals of this population with 39 molecular markers mapped on chromosome 1D revealed 88 radiation-induced breaks in this chromosome. This number of chromosome 1D breaks is eight times higher than the number of previously identified breaks and should result in a 10-fold increase in mapping resolution compared to what was previously possible. The analysis of molecular marker retention in our radiation hybrid mapping panel allowed the localization of scsae and 8 linked markers on the long arm of chromosome 1D. This constitutes the first report of using RH mapping to localize a gene in wheat and illustrates that this approach is feasible in a species with a large complex genome.