Cytokinin dehydrogenase differentially regulates cytokinin and indirectly affects hydrogen peroxide accumulation in tomato leaf.

Abstract

Cytokinin dehydrogenase (CKX) catalyzes the irreversible degradation of cytokinins (CKs). CKs play a role in the regulation of hydrogen peroxide (H(2)O(2)) accumulation while H(2)O(2) is involved in chlorophyll degradation. Here, we elucidated how CKX differentially regulates representative CK levels and indirectly influence H(2)O(2) accumulation in tomato leaves. We induced drought, salt and iron-deficiency stresses in tomato plants and found that chlorosis-inducing stresses (salt and iron-deficiency) induced lower chlorophyll levels as compared to drought stress and control. Protein gel blot analysis detected two CKXs in tomato leaves: a 35 kDa protein (CKX35) found in chlorotic leaves associated with a reduction in representative CK levels and high H(2)O(2) concentrations, and a 37 kDa protein (CKX37) found in green leaves associated with representative CKs and H(2)O(2) at normal levels. In summary, CKX isoforms in the tomato leaf appear to have distinct roles in differentially regulating CK levels and indirectly influencing H(2)O(2) accumulation.

• Authors: Marni E Cueno, Kenichi Imai, Kuniyasu Ochiai, Takashi Okamoto
• Journal: Journal of plant physiology (J Plant Physiol) Vol. 169 Issue 8 Pg. 834-8 (May 15 2012) ISSN: 1618-1328 [Electronic] Germany
• PMID: 22365258 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2012 Elsevier GmbH. All rights reserved.

Chemical References

• Cytokinins
• Plant Growth Regulators
• Hydrogen Peroxide
• Oxidoreductases
• cytokinin oxidase

Topics

• Cytokinins (metabolism)
• Hydrogen Peroxide (metabolism)
• Solanum lycopersicum (enzymology, metabolism)
• Oxidoreductases (metabolism)
• Plant Growth Regulators (metabolism)
• Plant Leaves (metabolism)
• Stress, Physiological