Genetic analysis of the expression of the cold-regulated gene cor14b: a way toward the identification of components of the cold response signal transduction in Triticeae

Extensive molecular biological studies have led to the cloning of many cold-regulated genes (cor) whose expression is up-regulated in winter cereals during exposure to cold. Among them is cor14b, a nuclear gene coding for a chloroplast-localized protein whose expression level has been associated with frost resistance in Triticeae. Although frost tolerance is recognised as a complex quantitative character, members of homologous group 5 in Triticeae are known to carry major loci determining frost tolerance. In this work we summarize a number of recent experiments where the cold-regulated gene cor14b was used as a tool (i) to understand the genetic relationship between the expression of cor genes and the frost resistance loci and (ii) to identify barley mutants revealing a chloroplast role in the signal transduction pathway leading to the molecular cold response.