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Bioorganic Chemistry
Biochemistry of Plant Interactions
Cell and Metabolic Biology
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Publications - Cell and Metabolic Biology
Publications
Jasmonates are lipid-derived plant hormones that regulate plant defenses and numerous developmental processes. Although the biosynthesis and molecular function of the most active form of the hormone, (+)-7-iso-jasmonoyl-L-isoleucine (JA-Ile), have been unraveled, it remains poorly understood how the diversity of bioactive jasmonates regulates such a multitude of plant responses. Bioactive analogs have been used as chemical tools to interrogate the diverse and dynamic processes of jasmonate action. By contrast, small molecules impairing jasmonate functions are currently unknown. Here, we report on jarin-1 as what is to our knowledge the first small-molecule inhibitor of jasmonate responses that was identified in a chemical screen using Arabidopsis thaliana. Jarin-1 impairs the activity of JA-Ile synthetase, thereby preventing the synthesis of the active hormone, JA-Ile, whereas closely related enzymes are not affected. Thus, jarin-1 may serve as a useful chemical tool in search for missing regulatory components and further dissection of the complex jasmonate signaling networks.
Publications
In barley leaves a group of genes is expressed in response to treatment with jasmonates and abscisic acid (ABA) [21]. One of these genes coding for a jasmonate-induced protein of 23 kDa (JIP-23) was analyzed to find out the link between ABA and jasmonates by recording its expression upon modulating independently, the endogenous level of both of them. By use of inhibitors of JA synthesis and ABA degradation, and the ABA-deficient mutant Az34, as well as of cultivar-specific differences, it was shown that endogenous jasmonate increases are necessary and sufficient for expression of this gene. The endogenous rise of ABA did not induce synthesis of JIP-23, whereas exogenous ABA did not act via jasmonates. Different signalling pathways are suggested and discussed.
Publications
This article surveys the currently isolated and identified GA conjugates, their synthesis and evaluates modern methods for analysing GA glucose conjugates. The metabolism of applied GAs in higher plant systems leading, in most cases, to GA conjugates is also considered. The enzymology of the formation and hydrolysis of GA glucose conjugates is discussed in connection with their possible physiological function.
Publications
Data on the occurrence of free and conjugated gibberellins in different tribes of Gramineae are compiled and discussed with regard to their biosynthetic pathways. From the gibberellins detected so far the functioning of both the early 13-hydroxylation and the non-3,13-hydroxylation pathway of GA biosynthesis in gramineous plants can be deduced and the discovery of further gibberellin conjugates may be expected.
This page was last modified on 27 Jan 2025 .
