ORGANIZATION AND EXPRESSION OF A POTATO (SOLANUM-TUBEROSUM) PROTEIN-KINASE GENE

A 4.3 kb genomic clone from potato (Solanum tuberosum) cv. Saturna has been isolated which contains the full coding sequence of a protein ki nase gene (Stpk1), 1 kb of 3' sequence, and the first exon of a neighb ouring gene encoding a sucrolytic enzyme. An identical organisation co uld be detected in a genomic clone carrying a gene that encodes a prot ein kinase homologue: in Arabidopsis thaliana (Hayashida et al., Gene, 121 (1992) 325-330). Southern and RT-PCR analyses indicate that Stpkl is a single copy gene which is expressed throughout the plant with an increase in transcript abundance in leaf after infection with Phytoph thora infestans. While comparisons using the deduced amino. acid seque nce for STPK1 indicate that it is most closely related to cyclic nucle otide-dependent protein kinases, it contains an additional plant-speci fic insert of 85 amino acids in the catalytic domain.