Abstract

Cold tolerance in plants is a multigenic trait and high levels of tolerance require a period of acclimation during which the expression levels of many genes are known to change. The study of the signaling and regulatory mechanisms that control acclimation is particularly important for understanding the genetic basis of cold tolerance in plants. Previous microarray analysis has identified a number of genes that have altered expression during cold acclimation, some of which have characteristics of signaling or regulatory proteins. Since GTP-binding proteins have been shown to be important regulatory proteins in animal systems, the recently discovered cold regulated GTP-binding-like protein, J822, from wheat, was chosen for this study. The predicted amino acid sequence of J822 indicated that it encodes a novel GTP-binding protein. Cold induction of transcript level of J822 is higher in cold tolerant winter cultivars than in spring wheat cultivars. Yeast two-hybrid screening showed that J822 interacts with two phospholipase C proteins. J822 and the phospholipase Cs were found to be regulated by cold, drought and salt stress and may be involved in stress-induced phospholipid signaling. The Arabidopsis homolog of J822 is also regulated by cold, and provides a promising avenue for the functional study of this GTP binding protein as part of the stress response