Isolation of CrHPt1, a cDNA encoding a histidine-containing phospho-transfer domain in Catharanthus roseus

Abstract

It is now accepted that some signal transduction systems in plants are built of modules that are homologous to the autophosphorylating histidine kinases, the histidine-containing phosphotransfer (HPt) domains and the response regulators that compose two-component systems (TCS) as well as multistep phosphorelay systems (MPS) firstly uncovered in Prokaryotes. There are now good evidences that TCS and MPS play crucial roles in the signaling pathways for ethylene and cytokinin, respectively. In the present study, a full length cDNA (designated CrHPt1) was isolated by PCR amplification of a cDNA library from periwinkle cell cultures. The deduced protein (151 amino acids) is 68% identical to the HPt protein AHP3 of Arabidopsis thaliana. Involvement of a HPt protein in the cytokinin signaling pathway leading to alkaloid biosynthesis enhancement in Madagascar periwinkle cell cultures is discussed.