GrainGenes Reference Report: TAG-112-373
Reference
TAG-112-373
Title
Map-based analysis of genes affecting the brittle rachis character in tetraploid wheat (Triticum turgidum L.).
Journal
Theoretical and Applied Genetics
Year
2006
Volume
112
Pages
373-381
Author
Nalam VJ Vales MI Watson CJW Kianian SF Riera-Lizarazu O
Abstract
The mature spike rachis of wild emmer [Triticum turgidum L. ssp. dicoccoides (Korn. ex Asch. and Graebner) Thell.] disarticulates spontaneously between each spikelet leading to the dispersion of wedge-type diaspores. By contrast, the spike rachis of domesticated emmer (Triticum turgidum L. ssp. turgidum) fails to disarticulate and remains intact until it is harvested. This major distinguishing feature between wild and domesticated emmer is controlled by two major genes, brittle rachis 2 (Br-A2) and brittle rachis 3 (Br-A3) on the short arms of chromosomes 3A and 3B, respectively. Because of their biological and agricultural importance, a map-based analysis of these genes was undertaken. Using two recombinant inbred chromosome line (RICL) populations, Br-A2, on chromosome 3A, was localized to a similar to 11-cM region between Xgwm2 and a cluster of linked loci (Xgwm666.1, Xbarc19, Xcfa2164, Xbarc356, and Xgwm674), whereas Br-A3, on chromosome 3B, was localized to a similar to 24-cM interval between Xbarc218 and Xwmc777. Comparative mapping analyses suggested that both Br-A2 and Br-A3 were present in homoeologous regions on chromosomes 3A and 3B, respectively. Furthermore, Br-A2 and Br-A3 from wheat and Btr1/Btr2 on chromosome 3H of barley (Hordeum vulgare L.) also were homoeologous suggesting that the location of major determinants of the brittle rachis trait in these species has been conserved. On the other hand, brittle rachis loci of wheat and barley, and a shattering locus on rice chromosome 1 did not appear to be orthologous. Linkage and deletion-based bin mapping comparisons suggested that Br-A2 and Br-A3 may reside in chromosomal areas where the estimated frequency of recombination was similar to 4.3 Mb/cM. These estimates indicated that the cloning of Br-A2 and Br-A3 using map-based methods would be extremely challenging.
External Databases
https://doi.org/10.1007/s00122-005-0140-y
Gene
Br-A1 (Triticum) Br-A2 (Triticum)
Locus
Br-A1 Br-B1
GrainGenes is a product of the Agricultural Research Service of the US Department of Agriculture.
GrainGenes Reference Report: TAG-112-373
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GrainGenes is a product of the Agricultural Research Service of the US Department of Agriculture. | |||