1. Zeatin Cis-Trans Isomerase in Plants Tomáš HLUSKA Department of Molecular Biology Centre of the Region Haná for Biotechnological and Agricultural Research

2. Zeatin interconversions

3. Zeatin Cis-Trans Isomerase

4. Existence of the enzyme is questionable due to several reasons:  Only one article describing in vitro activity and only one article describing in vivo activity  High non-enzymatic conversion  Need to light on reaction  Arabidopsis IPT knock-outs have lowered levels of tZ or cZ (Miyawaki et al. 2006)  Side chain of tZ and cZ originates from distinct pathways (Kasahara et al. 2004)

5. ZI activity in plants Upon salt stress, the activity rises in root, while decreases in shoot.

6. ZI activity in plants

7. Purification of ZmZI starting material: 3 days old roots of maize – 379 g

8. Zeatin Cis-Trans Isomerase glucan exohydrolase NAD-dep malate dehydrogenase peptidoglycan binding nucleoside diphosphate binding peroxidase xylanase inhibitor phosphoglycerate kinase serine protease phosphoglycerate mutase aspartate protease heat shock protein FAD-binding protein alpha-glucosidase; xylosidase ferredoxin NADP-reductase chitinase polyamine oxidase nodulin vicilin; globulin purple acid phosphatase lactoylglutathione lyase; glyoxylase beta-galactosidase aldose reductase nuclease lecithin:cholesterol acyltransferase methionine synthase acyl-CoA binding protein

9. Properties of ZmZI

11. Thank you for your attention