1. Jasmonic acid-isoleucine formation in grapevine (Vitis vinifera L.) by two enzymes with distinct transcription profiles.
- Author
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Böttcher C, Burbidge CA, di Rienzo V, Boss PK, and Davies C
- Subjects
- Acetates pharmacology, Amino Acids metabolism, Chromatography, Liquid, Cyclopentanes pharmacology, Fruit drug effects, Fruit genetics, Fruit growth & development, Gene Expression Regulation, Plant drug effects, Genes, Plant, Isoleucine biosynthesis, Mass Spectrometry, Organ Specificity drug effects, Organ Specificity genetics, Oxylipins pharmacology, Plant Leaves drug effects, Plant Leaves genetics, Recombinant Proteins metabolism, Substrate Specificity drug effects, Vitis drug effects, Vitis growth & development, Gene Expression Profiling, Isoleucine analogs & derivatives, Transcription, Genetic drug effects, Vitis enzymology, Vitis genetics
- Abstract
The plant hormone jasmonic acid (JA) is essential for stress responses and the formation of reproductive organs, but its role in fruit development and ripening is unclear. Conjugation of JA to isoleucine is a crucial step in the JA signaling pathway since only JA-Ile is recognized by the jasmonate receptor. The conjugation reaction is catalyzed by JA-amido synthetases, belonging to the family of Gretchen Hagen3 (GH3) proteins. Here, in vitro studies of two grapevine (Vitis vinifera L. cv Shiraz) GH3 enzymes, VvGH3-7 and VvGH3-9, demonstrated JA-conjugating activities with an overlapping range of amino acid substrates, including isoleucine. Expression studies of the corresponding genes in grape berries combined with JA and JA-Ile measurements suggested a primary role for JA signaling in fruit set and cell division and did not support an involvement of JA in the ripening process. In response to methyl JA (MeJA) treatment, and in wounded and unwounded (distal) leaves, VvGH3-9 transcripts accumulated, indicating a participation in the JA response. In contrast, VvGH3-7 was unresponsive to MeJA and local wounding, demonstrating a differential transcriptional regulation of VvGH3-7 and VvGH3-9. The transient induction of VvGH3-7 in unwounded, distal leaves was suggestive of the involvement of an unknown mobile wound signal., (© 2014 Institute of Botany, Chinese Academy of Sciences.)
- Published
- 2015
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