Abstract
Fruit set is initiated only after fertilization and is tightly regulated primarily by gibberellins (GAs) and auxins. The application of either of these hormones induces parthenocarpy, fruit set without fertilization, but the molecular mechanism underlying this induction is poorly understood. In the present study, we have shown that the parthenocarpic fruits induced by GA application at pre-bloom result from the interaction of GA with auxin signaling. The transcriptional levels of the putative negative regulators of fruit set initiation, including Vitis auxin/indole-3-acetic acid transcription factor 9 (VvIAA9), Vitis auxin response factor 7 (VvARF7), and VvARF8 were monitored during inflorescence development in seeded diploid 'Tamnara' grapevines with or without GA application. Without GA application, VvIAA9, VvARF7, and VvARF8 were expressed at a relatively high level before full bloom, but decreased thereafter following pollination. After GA application at 14 days before full bloom (DBF); however, the expression levels of VvIAA9 and VvARF7 declined at 5 DBF prior to pollination. The effects of GA application on auxin levels or auxin signaling were also analyzed by monitoring the expression patterns of auxin biosynthesis genes and auxin-responsive genes with or without GA application. Transcription levels of the auxin biosynthesis genes Vitis anthranilate synthase β subunit (VvASB1-like), Vitis YUCCA2 (VvYUC2), and VvYUC6 were not significantly changed by GA application. However, the expressions of Vitis Gretchen Hagen3.2 (VvGH3.2) and VvGH3.3, auxin-responsive genes, were up-regulated from 2 DBF to full bloom with GA application. Furthermore, the Vitis GA signaling gene, VvDELLA was up-regulated by GA application during 12 DBF to 7 DBF, prior to down-regulation of VvIAA9 and VvARF7. These results suggest that VvIAA9 and VvARF7 are negative regulators of fruit set initiation in grapevines, and GA signaling is integrated with auxin signaling via VvDELLA during parthenocarpic fruit development in grapevines.
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Claims 9
Claim · model-written summary
Pre-bloom GA application induced parthenocarpic fruits.
VitisNot reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Grapevines”
e0“the parthenocarpic fruits induced by GA application at pre-bloom”
Claim · model-written summary
Without GA, VvIAA9, VvARF7, and VvARF8 expression was relatively high before full bloom and decreased after pollination.
- Gene
- VvIAA9, VvARF7, and VvARF8e0
- Outcome
- expressed at a relatively high level before full bloome0
- Direction
- decreasede0
- Qualifier
- following pollinatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Grapevines”
e0“Without GA application, VvIAA9, VvARF7, and VvARF8 were expressed at a relatively high level before full bloom, but decreased thereafter following pollination”
Claim · model-written summary
GA application advanced the decline of VvIAA9 expression to five days before full bloom.
- Treatment
- GA application at 14 days before full bloom (DBF)e0
- Gene
- VvIAA9e0
- Outcome
- expression levels of VvIAA9e0
- Direction
- declinede0
- Qualifier
- 5 DBF prior to pollinatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Grapevines”
e0“After GA application at 14 days before full bloom (DBF); however, the expression levels of VvIAA9 and VvARF7 declined at 5 DBF prior to pollination”
Claim · model-written summary
GA application advanced the decline of VvARF7 expression to five days before full bloom.
- Treatment
- GA application at 14 days before full bloom (DBF)e0
- Gene
- VvARF7e0
- Outcome
- expression levels of VvIAA9 and VvARF7e0
- Direction
- declinede0
- Qualifier
- 5 DBF prior to pollinatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Grapevines”
e0“After GA application at 14 days before full bloom (DBF); however, the expression levels of VvIAA9 and VvARF7 declined at 5 DBF prior to pollination”
Claim · model-written summary
GA application did not significantly alter transcription of VvASB1-like, VvYUC2, or VvYUC6.
- Treatment
- GA applicatione0
- Gene
- VvASB1-like), Vitis YUCCA2 (VvYUC2), and VvYUC6e0
- Outcome
- Transcription levelse0
- Direction
- not significantly changede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Grapevines”
e0“Transcription levels of the auxin biosynthesis genes Vitis anthranilate synthase β subunit (VvASB1-like), Vitis YUCCA2 (VvYUC2), and VvYUC6 were not significantly changed by GA application”
Claim · model-written summary
GA upregulated auxin-responsive VvGH3.2 and VvGH3.3 from two days before full bloom through full bloom.
- Treatment
- GA applicatione0
- Gene
- VvGH3.2) and VvGH3.3e0
- Outcome
- expressionse0
- Direction
- up-regulatede0
- Qualifier
- from 2 DBF to full bloome0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Grapevines”
e0“the expressions of Vitis Gretchen Hagen3.2 (VvGH3.2) and VvGH3.3, auxin-responsive genes, were up-regulated from 2 DBF to full bloom with GA application”
Claim · model-written summary
GA upregulated VvDELLA from 12 to 7 days before full bloom.
- Treatment
- GA applicatione0
- Gene
- VvDELLAe0
- Outcome
- VvDELLAe0
- Direction
- up-regulatede0
- Qualifier
- during 12 DBF to 7 DBFe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Grapevines”
e0“VvDELLA was up-regulated by GA application during 12 DBF to 7 DBF”
Claim · model-written summary
The authors infer that VvIAA9 and VvARF7 negatively regulate fruit set initiation.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Grapevines”
e0“These results suggest that VvIAA9 and VvARF7 are negative regulators of fruit set initiation in grapevines”
Claim · model-written summary
The authors infer GA and auxin signaling integration via VvDELLA during parthenocarpic fruit development.
- Gene
- VvDELLAe0
- Outcome
- parthenocarpic fruit developmente0
- Qualifier
- GA signaling is integrated with auxin signalinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Grapevines”
e0“GA signaling is integrated with auxin signaling via VvDELLA during parthenocarpic fruit development in grapevines”
The same questions in other papers
Gibberellic acid · molecular: expression · VitisPositive and negative results
4 papers in the same direction as this paper · 7 in the opposite direction
- positive
- positive
- negative
8 papers more in this group
See all 12 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.