DELLA-GAF1 complex is involved in tissue-specific expression and gibberellin feedback regulation of GA20ox1 in Arabidopsis
Key message The GAF1 transcription factor is shown to bind to the promoter of the Arabidopsis GA-biosynthetic enzyme GA20ox1 and, in association with DELLA protein, promotes GA20ox1 expression, thereby contributing to its feedback regulation and tissue specificity. Gibberellins (GAs) are phytohormon...
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Published in | Plant molecular biology Vol. 107; no. 3; pp. 147 - 158 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
Dordrecht
Springer Netherlands
01.10.2021
Springer Nature B.V |
Subjects | |
Online Access | Get full text |
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Summary: | Key message
The GAF1 transcription factor is shown to bind to the promoter of the Arabidopsis GA-biosynthetic enzyme GA20ox1 and, in association with DELLA protein, promotes
GA20ox1
expression, thereby contributing to its feedback regulation and tissue specificity.
Gibberellins (GAs) are phytohormones that promote plant growth and development, including germination, elongation, flowering, and floral development. Homeostasis of endogenous GA levels is controlled by GA feedback regulation. DELLAs are negative regulators of GA signaling that are rapidly degraded in the presence of GAs. DELLAs regulate several target genes, including
AtGA20ox2
and
AtGA3ox1
, encoding the GA-biosynthetic enzymes GA 20-oxidase and GA 3-oxidase, respectively. Previous studies have identified GAI-ASSOCIATED FACTOR 1 (GAF1) as a DELLA interactor, with which DELLAs act as transcriptional coactivators; furthermore,
AtGA20ox2
,
AtGA3ox1
, and
AtGID1b
were identified as target genes of the DELLA-GAF1 complex. Among the five
Arabidopsis GA20ox
genes,
AtGA20ox1
is the most highly expressed gene during vegetative growth; its expression is controlled by GA feedback regulation. Here, we investigated whether
AtGA20ox1
is regulated by the DELLA-GAF1 complex. The electrophoretic mobility shift and transactivation assays showed that three GAF1-binding sites exist in the
AtGA20ox1
promoter. Using transgenic plants, we further evaluated the contribution of the DELLA-GAF1 complex to GA feedback regulation and tissue-specific expression. Mutations in two GAF1-binding sites obliterated the negative feedback regulation and tissue-specific expression of
AtGA20ox1
in transgenic plants. Thus, our results showed that GAF1-binding sites are involved in GA feedback regulation and tissue-specific expression of
AtGA20ox1
in Arabidopsis, suggesting that the DELLA-GAF1 complex is involved in both processes. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0167-4412 1573-5028 |
DOI: | 10.1007/s11103-021-01195-z |