Journal
JOURNAL OF EXPERIMENTAL BOTANY
Volume 64, Issue 14, Pages 4403-4419Publisher
OXFORD UNIV PRESS
DOI: 10.1093/jxb/ert251
Keywords
Anthesis; fruit set; gibberellin 2-hydroxylase; gibberellin 3-hydroxylase; gibberellin metabolism; gibberellin oxidase; grapevine; inflorescence; Vitis vinifera
Categories
Funding
- Autonomous Province of Trento (PAT-MArie Curie-Cofund)
Ask authors/readers for more resources
Gibberellins (GAs) are involved in the regulation of flowering and fruit-set in grapes (Vitis vinifera L.), but the molecular mechanisms behind this process are mostly unknown. In this work, the family of grapevine GA oxidases involved in the biosynthesis and deactivation of GAs was characterized. Six putative GA 20-oxidase (GA20ox), three GA 3-oxidase (GA3ox), and eight GA 2-oxidase (GA2ox) proteins, the latter further divided into five C-19-GA 2ox and three C-20-GA2ox proteins, were identified. Phylogenetic analyses suggest a common origin of the GA3ox and C-19-GA2ox groups and challenge previous evolutionary models. In vitro analysis revealed that all GA3ox and GA20ox enzymes prefer substrates of the non-13-hydroxylation pathway. In addition, ectopic expression of GA2ox genes in Arabidopsis thaliana confirmed the activity of their encoded proteins in vivo. The results show that bioactive GA(1) accumulates in opening grapevine flowers, whereas at later developmental stages only GA(4) is detected in the setting fruit. By studying the expression pattern of the grapevine GA oxidase genes in different organs, and at different stages of flowering and fruit-set, it is proposed that the pool of bioactive GAs is controlled by a fine regulation of the abundance and localization of GA oxidase transcripts.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available