Investigating Mechanisms of Cold Tolerance in Cereals By Comparing Whole-Chromosome Shotgun Assemblies of Wheat Chromosome 5A and the Long Arm of Rye Chromosome 5R

Low-temperature tolerance is an important agronomic trait for both spring and winter wheat crops.  Improvements to low-temperature tolerance in wheat have been limited by a lack of varieties with significantly greater tolerance than current cultivars.  An alternative source of low-temperature tolerance genes may be the closely related species rye, which displays the greatest tolerance of any temperate cereal.  Efforts to exploit the superior tolerance of rye for wheat improvement have not yet been successful, despite the identification of genomic regions involved in low-temperature tolerance in both species.

The cereal group 5 chromosomes, and in particular a region designated as Fr2, have been implicated in low-temperature tolerance. Using a subtractive approach we have assembled a chromosomal translocation of the long arm of rye variety Puma chromosome 5R, as well as chromosome 5A of the wheat variety Norstar.  These assemblies have been used for comparative analyses of the Fr2 loci.