A new role for the Arabidopsis AP2 transcription factor, LEAFY PETIOLE, in gibberellin-induced germination is revealed by the misexpression of a homologous gene, SOB2/DRN-LIKE

Jason M Ward; Alison M Smith; Purvi K Shah; Sarah E Galanti; Hankuil Yi; Agnes J Demianski; Eric van der Graaff; Beat Keller; Michael M Neff

doi:10.1105/tpc.105.036707

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A new role for the Arabidopsis AP2 transcription factor, LEAFY PETIOLE, in gibberellin-induced germination is revealed by the misexpression of a homologous gene, SOB2/DRN-LIKE

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A new role for the Arabidopsis AP2 transcription factor, LEAFY PETIOLE, in gibberellin-induced germination is revealed by the misexpression of a homologous gene, SOB2/DRN-LIKE

Jason M Ward, Alison M Smith, Purvi K Shah, Sarah E Galanti, Hankuil Yi, Agnes J Demianski, Eric van der Graaff, Beat Keller and Michael M Neff

The Plant cell, Vol.18(1), pp.29-39

01/2006

DOI: https://doi.org/10.1105/tpc.105.036707

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https://hdl.handle.net/2376/116502

PMID: 16339853

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Abstract

Germination - drug effects

Amino Acid Sequence

Darkness

Arabidopsis Proteins - genetics

Oligonucleotides, Antisense

Seedlings - anatomy & histology

Molecular Sequence Data

Transcription Factors - genetics

Arabidopsis - metabolism

Arabidopsis - genetics

Arabidopsis Proteins - metabolism

Transcription Factors - metabolism

Sequence Alignment

Seedlings - physiology

Seeds - physiology

Arabidopsis - anatomy & histology

Light

Gene Expression Regulation, Plant

Germination - physiology

Gibberellins - pharmacology

Signal Transduction - physiology

Plant Growth Regulators - pharmacology

Phenotype

Mutation

Gibberellic acid (GA) promotes germination, stem/hypocotyl elongation, and leaf expansion during seedling development. Using activation-tagging mutagenesis, we identified a mutation, sob2-D (for suppressor of phytochromeB-4 [phyB-4]#2 dominant), which suppresses the long-hypocotyl phenotype of a phyB missense allele, phyB-4. This mutant phenotype is caused by the overexpression of an APETALA2 transcription factor, SOB2, also called DRN-like. SOB2/DRN-like transcript is not detectable in wild-type seedling or adult tissues via RT-PCR analysis, suggesting that SOB2/DRN-like may not be involved in seedling development under normal conditions. Adult sob2-D phyB-4 plants have curled leaves and club-like siliques, resembling plants that overexpress a closely related gene, LEAFY PETIOLE (LEP). Hypocotyls of a LEP-null allele, lep-1, are shorter in the light and dark, suggesting LEP involvement in seedling development. This aberrant hypocotyl phenotype is due at least in part to a delay in germination. In addition, lep-1 is less responsive to GA and more sensitive to the GA biosynthesis inhibitor paclobutrazol, indicating that LEP is a positive regulator of GA-induced germination. RT-PCR shows that LEP transcript accumulates in wild-type seeds during imbibition and germination, and the transcript levels of REPRESSOR OF ga1-3-LIKE2 (RGL2), a negative regulator of GA signaling during germination, is unaffected in lep-1. These results suggest LEP is a positive regulator of GA-induced germination acting independently of RGL2. An alternative model places LEP downstream of RGL2 in the GA-signaling cascade.

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Title: A new role for the Arabidopsis AP2 transcription factor, LEAFY PETIOLE, in gibberellin-induced germination is revealed by the misexpression of a homologous gene, SOB2/DRN-LIKE
Creators: Jason M Ward - Department of Biology, Washington University, St. Louis, Missouri 63130, USA
Alison M Smith
Purvi K Shah
Sarah E Galanti
Hankuil Yi
Agnes J Demianski
Eric van der Graaff
Beat Keller
Michael M Neff
Publication Details: The Plant cell, Vol.18(1), pp.29-39
Academic Unit: Department of Crop and Soil Sciences
Publisher: United States
Identifiers: 99900548264101842
Language: English
Resource Type: Journal article