A novel plant protein kinase, designated Brassica napus kinase 1 (BNK1), was isolated from a λ-pistil cDNA library. The deduced BNK1 protein contains all eleven conserved subdomains of a kinase and encodes a functional serine/threonine protein kinase. Phylogenetic analysis of several plant protein kinase subfamilies showed that BNK1 is most closely related to the NAK subfamily of protein kinases. Genomic Southern blot analysis revealed that BNK1 is a single copy gene in the B. napus genome and does not appear to be a member of a multigene family. Expression studies revealed that the BNK1 transcript was ubiquitously expressed throughout the plant, with highest levels in stem and pistil tissues.