Function of plant defense secondary metabolite in cytokinin degradation

0359310 - ÚEB 2011 RIV US eng J - Journal Article
Frébortová, Jitka
Function of plant defense secondary metabolite in cytokinin degradation.
Plant Signaling & Behavior. Roč. 5, č. 5 (2010), s. 523-525. ISSN 1559-2316. E-ISSN 1559-2324
R&D Projects: GA ČR GA522/05/0448; GA ČR GA301/08/1649
Institutional research plan: CEZ:AV0Z50380511
Keywords : cytokinin dehydrogenace * 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one * phenoxyl radiál
Subject RIV: EF - Botanics
http://www.landesbioscience.com/journals/psb/article/10965/

The flavoenzyme cytokinin dehydrogenace (CKX) catalyzes an irreversible deactivation of plant hormones cytokinins through oxidative cleavage of the cytokinin side chain to Šeld adenine or adenosine and an aldehyde. In the catalytic cycle of CKX, the cytokinin-reduced flavin cofactor is reoxidized by a suitable electron acceptor. We have recently demonstrated that the oxidation products of natural hydroxamic acid 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) function as effective electron acceptors of apoplastic CKX from maize. The stable oxidation product of DIMBOA reacting with peroxidase or laccase was identified as 4-nitrosoresorcinol 1-monomethyl ether (coniferron), which, however, is only a weak electron acceptor of CKX. Further analyses suggested formativ of transient free radicals that were estimated to reoxidize the cytokininreduced flavin cofactor of CKX with the rates comparable to those of flavin reduction.
Permanent Link: http://hdl.handle.net/11104/0197114