Abstract
Gibberellins (GAs) play important roles in regulating reproductive development, especially anther development. Our previous studies revealed that the MYB transcriptional factor GAMYB, an important component of GA signaling in cereal aleurone cells, is also important for anther development. Here, we examined the physiological functions of GA during anther development through phenotypic analyses of rice (Oryza sativa) GA-deficient, GA-insensitive, and gamyb mutants. The mutants exhibited common defects in programmed cell death (PCD) of tapetal cells and formation of exine and Ubisch bodies. Microarray analysis using anther RNAs of these mutants revealed that rice GAMYB is involved in almost all instances of GA-regulated gene expression in anthers. Among the GA-regulated genes, we focused on two lipid metabolic genes, a cytochrome P450 hydroxylase CYP703A3 and beta-ketoacyl reductase, both of which might be involved in providing a substrate for exine and Ubisch body. GAMYB specifically interacted with GAMYB binding motifs in the promoter regions in vitro, and mutation of these motifs in promoter-beta-glucuronidase (GUS) transformants caused reduced GUS expression in anthers. Furthermore, a knockout mutant for CYP703A3 showed gamyb-like defects in exine and Ubisch body formation. Together, these results suggest that GA regulates exine formation and the PCD of tapetal cells and that direct activation of CYP703A3 by GAMYB is key to exine formation.
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Claims 8
Claim · model-written summary
GA-deficient, GA-insensitive, and gamyb mutants had common tapetal PCD defects.
- Taxon
- rice
Oryza sativat0 - Material
- mutantse0
- Organ / stage
- tapetal cellse0
- Outcome
- defects in programmed cell death (PCD) of tapetal cellse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The mutants exhibited common defects in programmed cell death (PCD) of tapetal cells”
t0“Rice”
Claim · model-written summary
The same mutants had defects in exine and Ubisch body formation.
- Taxon
- riceOryza sativat0
- Material
- mutantse0
- Organ / stage
- exine and Ubisch bodiese0
- Outcome
- formation of exine and Ubisch bodiese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The mutants exhibited common defects in programmed cell death (PCD) of tapetal cells and formation of exine and Ubisch bodies”
t0“Rice”
Claim · model-written summary
GAMYB was involved in nearly all GA-regulated gene expression in rice anthers.
- Taxon
- riceOryza sativae0
- Organ / stage
- antherse0
- Gene
- rice GAMYBe0
- Outcome
- GA-regulated gene expressione0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“rice GAMYB is involved in almost all instances of GA-regulated gene expression in anthers”
Claim · model-written summary
GAMYB interacted with promoter binding motifs in vitro.
- Taxon
- riceOryza sativat0
- Gene
- GAMYBe0
- Outcome
- interacted with GAMYB binding motifse0
- Setting
- in vitroe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“GAMYB specifically interacted with GAMYB binding motifs in the promoter regions in vitro”
t0“Rice”
Claim · model-written summary
Mutation of promoter motifs reduced GUS expression in anthers.
- Taxon
- riceOryza sativat0
- Organ / stage
- antherse0
- Treatment
- mutation of these motifse0
- Outcome
- GUS expressione0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“mutation of these motifs in promoter-beta-glucuronidase (GUS) transformants caused reduced GUS expression in anthers”
t0“Rice”
Claim · model-written summary
CYP703A3 knockout had gamyb-like defects in exine and Ubisch body formation.
- Taxon
- riceOryza sativat0
- Treatment
- a knockout mutant for CYP703A3e0
- Gene
- CYP703A3e0
- Outcome
- defects in exine and Ubisch body formatione0
- Comparator
- gamybe0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a knockout mutant for CYP703A3 showed gamyb-like defects in exine and Ubisch body formation”
t0“Rice”
Claim · model-written summary
The results suggest GA regulates exine formation and tapetal PCD.
- Taxon
- riceOryza sativat0
- Outcome
- exine formation and the PCD of tapetal cellse0
- Qualifier
- GAe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“GA regulates exine formation and the PCD of tapetal cells”
t0“Rice”
Claim · model-written summary
The results suggest direct CYP703A3 activation by GAMYB is key to exine formation.
- Taxon
- riceOryza sativat0
- Gene
- CYP703A3e0
- Outcome
- exine formatione0
- Qualifier
- direct activation of CYP703A3 by GAMYBe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“direct activation of CYP703A3 by GAMYB is key to exine formation”
t0“Rice”
The same questions in other papers
loss of function · molecular: expression · Oryza sativa (rice)Positive and negative results
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