Molecular cloning of protein phosphates and protein kinase genes from crop plants

Protein kinases and protein phosphatases are two very large enzyme families functioning in many important cellular processes such as regulation of cell cycle, signal transduction, self-incompatibility and disease resistance in plants. Some members of these two families have been cloned and subjected to detailed studies, but the majority remains unidentified, especially in plants. Barley and maize are two important crops in the world and also excellent experimental organisms particularly in the area of molecular genetics. Genes encoding protein kinase have been cloned from maize and barley, however, genes encoding protein phosphatase have not been cloned from barley. The signal transduction pathways involving the cloned protein kinases and protein phosphatases in maize and barley are not known. Since the amino acid sequences in the catalytic domains of protein kinase and protein phosphatase is conserved within eukaryotes, our approach consisted of using homology based screening to isolate novel protein kinases from maize cDNA library, and protein phosphatases from barley genomic library.