Abstract
trans-Zeatin (tZ) is one of cytokinins (CKs) that induce cell division and differentiation of the plant in the presence of auxin. We have recently demonstrated that tZ-type CKs are mainly produced using dimethylallyl diphosphate from the plastidic methylerythritol phosphate (MEP) pathway in Arabidopsis seedlings. Interestingly, tZ-type CKs were also partially produced through the cis-trans isomerization of cis-zeatin (cZ)-type CKs, of which prenyl side chains are derived from the cytosolic MVA pathway. To elucidate CK biosynthesis in cultured cell lines of plant, we carried out feeding experiments using 13C-labeled precursors of the MEP/MVA pathways. We will present the results from feeding experiments in Arabidopsis T87 cells and tobacco BY2 cells which do not require exogenous CK in the medium.
