Sucrose non-fermenting-1-related protein kinases (SnRKs) may play a major role in regulating gene expression in plant cells. This family of regulatory proteins is represented by sucrose non-fermenting-1 (SNF1) protein kinase in Saccharomyces cerevisiae, AMP-activated protein kinases (AMPKs) in mammals and SnRKs in higher plants. The SnRK family has been reorganized into three subfamilies according to the evolutionary relationships of their amino acid sequences. Members of the SnRK subfamily have been identified in several plants. There is evidence that they are involved in the nutritional and/or environmental stress response, although their roles are not yet well understood. We have identified at least 22 sugarcane expressed sequence tag (EST) contigs encoding putative SnRKs. The amino acid sequence alignment of both putative sugarcane SnRKs and known SnRKs revealed a highly conserved N-terminal catalytic domain. Our results indicated that sugarcane has at least one member of each SnRK subfamily. Expression pattern analysis of sugarcane EST-contigs encoding putative SnRKs in 26 selected cDNA libraries from the sugarcane expressed sequence tag SUCEST database has indicated that members of this family are expressed throughout the plant. Members of the same subfamily showed no specific expression patterns, suggesting that their functions are not related to their phylogenic relationships based on N-terminal amino acid sequence phylogenetic relationships.
