Abstract
Cytokinin plays crucial roles in diverse aspects of plant growth and development. Most active cytokinin is trans-zeatin (tZ). In the biosynthesis pathway, the nucleotide form is initially produced as cytokinin precursor. It is expected that two pathways be involved in production of tZ from the nucleotide: two-step activation pathway and direct activation pathway. In the two-step pathway, the nucleotides are converted to the nucleosides by nucleotidase and then to tZ by nucleosidase. On the other hand, in the direct pathway, the nucleotides are converted to tZ in one step. However, the biological roles of each pathway remain unclear.
Although the genes related in two-step pathway are not indentified, LONELY GUY (LOG) was previously identified as a cytokinin-activating enzyme that works in the direct pathway.
To study the biological roles of the direct pathway, we analyzed multiple knock out mutant of Arabidopsis LOGs (AtLOG1-5, 7-8). In addition, we monitored cytokinin metabolic fluxes by using stable isotope.
