Abstract

Cold tolerance in plants is a complex trait that occurs in many plants during growth at low temperature, a process known as cold acclimation. This process is a multigenic system and there is broad variation in the range of freezing tolerance that can be achieved by different wheat cultivars. To identify genes that are regulated by cold treatment and to characterize their expression profiles a microarray was constructed with PCR amplified cDNA inserts from 1187 wheat Expressed Sequence Tags (ESTs) that represent 948 genes. Two Triticum aestivum L. cultivars, Norstar and Glenlea that differ in their capacity to develop freezing tolerance were used to compare the changes in gene expression during cold acclimation. Microarray analysis is a powerful and rapid approach to gene discovery and for studying global gene expression. In species in which large scale mutant screening and transgenic studies are not currently practical, genotype comparison is an especially good approach to identify candidate genes for important agronomic traits. The analysis reveals that the transcript levels of over 300 genes were altered by cold treatment. Among these, 65 genes were differently regulated in the freezing-tolerant and the less-freezing-tolerant cultivars on at least one time point. These genes encode for protein kinases, putative transcription factors, Ca 2+ binding proteins, Golgi localized protein, inorganic pyrophosphatase, cell wall associated hydrolase, 2-oxoglutarate/malate translocator, and aspartate-tRNA ligase.