Our long range goal is to understand the "genomic" bases for cold tolerance. Our focus here will be on developing a more detailed understanding of how plants respond to low temperature in terms of altering gene expression. This emphasis is largely motivated by recent findings indicating that the cold acclimation response involves the action of genes that are induced upon exposing plants to low temperature. Our project will comprise three related lines of investigation.

1. To construct a low temperature "wiring diagram" that includes a definition of low temperature regulatory circuits and the gene regulons that they control
Specific objectives of this line of investigation include determining the composition of the low temperature transcriptome (i.e., the array of gene transcripts that change in levels in response to low temperature); organizing cold-regulated genes into regulons; identifying genetic loci that control expression of the regulons; and determining which regulons have important roles in cold tolerance.

2. To determine whether the Arabidopsis CBF cold-response pathway is highly conserved in plants
Specific objectives of this line of investigation include determining the structure and expression of CBF loci in plants that differ in freezing tolerance; determining whether transferring CBF loci from freezing tolerant plants to freezing sensitive plants affects cold tolerance; determining whether the major freezing tolerance locus barley encodes CBF genes or regulators of the CBF genes; and characterizing the makeup of CBF regulons in plants that differ in freezing tolerance.

3. To compare the battery of low temperature regulated genes in plants that differ in freezing tolerance
These lines of investigation will provide a deeper understanding of the "genomic mechanisms" that plants have evolved to cope with low temperature and have the potential to provide "genetic tools" to improve the chilling and freezing tolerance of plants, traits of considerable agronomic and economic importance.