AtSOFL1 and AtSOFL2 act redundantly as positive modulators of the endogenous content of specific cytokinins in Arabidopsis

Jingyu Zhang; Radomira Vankova; Jiri Malbeck; Petre I Dobrev; Yunyuan Xu; Kang Chong; Michael M Neff

doi:10.1371/journal.pone.0008236

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AtSOFL1 and AtSOFL2 act redundantly as positive modulators of the endogenous content of specific cytokinins in Arabidopsis

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AtSOFL1 and AtSOFL2 act redundantly as positive modulators of the endogenous content of specific cytokinins in Arabidopsis

Jingyu Zhang, Radomira Vankova, Jiri Malbeck, Petre I Dobrev, Yunyuan Xu, Kang Chong and Michael M Neff

PloS one, Vol.4(12), pp.e8236-e8236

12/09/2009

DOI: https://doi.org/10.1371/journal.pone.0008236

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https://hdl.handle.net/2376/113747

PMCID: PMC2785485

PMID: 20011053

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Abstract

Protein Structure, Tertiary

Darkness

Arabidopsis Proteins - genetics

Arabidopsis - drug effects

Gene Silencing - drug effects

Arabidopsis - growth & development

Genes, Plant

Mutagenesis, Insertional - drug effects

Hypocotyl - growth & development

Protein Transport - drug effects

Structure-Activity Relationship

Cytokinins - pharmacology

Mutation - genetics

Reverse Transcriptase Polymerase Chain Reaction

Arabidopsis - metabolism

Arabidopsis - genetics

Arabidopsis Proteins - metabolism

Gene Expression Regulation, Plant - drug effects

Phenotype

Arabidopsis Proteins - chemistry

Plants, Genetically Modified

Cytokinins - metabolism

Hypocotyl - drug effects

Although cytokinins have been known for decades to play important roles in the regulation of plant growth and development, our knowledge of the regulatory mechanism of endogenous content of specific cytokinins remains limited. Here, we characterized two SOB five-like (SOFL) genes, AtSOFL1 and AtSOFL2, in Arabidopsis (Arabidopsis thaliana) and showed that they acted redundantly in regulating specific cytokinin levels. Analysis of the translational fusion AtSOFL1:AtSOFL1-GUS and AtSOFL2:AtSOFL2-GUS indicated that AtSOFL1 and AtSOFL2 exhibited similar expression patterns. Both proteins were predominantly expressed in the vascular tissues of developing leaves, flowers and siliques, but barely detectable in roots and stems. Overexpression of either AtSOFL1 or AtSOFL2 led to increased cytokinin content and obvious corresponding mutant phenotypes for both transgenic seedlings and adult plants. In addition, overexpression and site-directed mutagenesis experiments demonstrated that the SOFL domains are necessary for AtSOFL2's overexpression phenotypes. Silencing or disrupting either AtSOFL1 or AtSOFL2 caused no obvious developmental defects. Endogenous cytokinin analysis, however, revealed that compared to the wild type control, the SOFL1-RNAi62 sofl2-1 double mutant accumulated lower levels of trans-zeatin riboside monophosphate (tZRMP) and N(6)-(Delta(2)-isopentenyl)adenosine monophosphate (iPRMP), which are biosynthetic intermediates of bioactive cytokinins. The double mutant also displayed decreased response to exogenous cytokinin in both callus-formation and inhibition-of-hypocotyl-elongation assays. Taken together, our data suggest that in plants AtSOFL1 and AtSOFL2 work redundantly as positive modulators in the fine-tuning of specific cytokinin levels as well as responsiveness.

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Title: AtSOFL1 and AtSOFL2 act redundantly as positive modulators of the endogenous content of specific cytokinins in Arabidopsis
Creators: Jingyu Zhang - Key Laboratory of Photosynthesis and Molecular Environmental Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China
Radomira Vankova
Jiri Malbeck
Petre I Dobrev
Yunyuan Xu
Kang Chong
Michael M Neff
Publication Details: PloS one, Vol.4(12), pp.e8236-e8236
Academic Unit: Crop and Soil Sciences, Department of
Publisher: United States
Identifiers: 99900547304401842
Language: English
Resource Type: Journal article