Functional analysis of HvSPY, a negative regulator of GA response, in barley aleurone cells and Arabidopsis

Filardo, Fiona, Robertson, Masumi, Singh, Davinder Pal, Parish, Roger W. and Swain, Stephen M. (2009) Functional analysis of HvSPY, a negative regulator of GA response, in barley aleurone cells and Arabidopsis. Planta, 229 3: 523-537. doi:10.1007/s00425-008-0843-9


Author Filardo, Fiona
Robertson, Masumi
Singh, Davinder Pal
Parish, Roger W.
Swain, Stephen M.
Title Functional analysis of HvSPY, a negative regulator of GA response, in barley aleurone cells and Arabidopsis
Formatted title
Functional analysis of HvSPY, a negative regulator of GA response, in barley aleurone cells and Arabidopsis
Journal name Planta   Check publisher's open access policy
ISSN 0032-0935
1432-2048
Publication date 2009-02
Year available 2008
Sub-type Article (original research)
DOI 10.1007/s00425-008-0843-9
Volume 229
Issue 3
Start page 523
End page 537
Total pages 15
Place of publication Heidelberg, Germany
Publisher Springer
Language eng
Formatted abstract
SPINDLY (SPY) is an important regulator of plant development, and consists of an N-half tetratricopeptide repeat (TPR) domain containing 10 TPR motifs and a C-half catalytic domain, similar to O-GlcNAc transferase (OGT) of animals. The best characterised role of SPY is a negative regulator of GA signalling, and all known spy alleles have been isolated based on increased GA response. Of the eight alleles that directly affect the TPR domain, all alter TPRs 6, 8 and/or 9. To test the hypothesis that a subset of TPRs, including 6, 8 and 9, are both essential and sufficient for the regulation of GA response, we overexpressed the full-length barley (Hordeum vulgare L.) SPY protein (HvSPY) and several deletion mutants in barley aleurone cells and in Arabidopsis wild type (WT) and spy-4 plants. Transient assays in barley aleurone cells, that also express endogenous HvSPY, demonstrated that introduced HvSPY and HvTPR inhibited GA 3-induced α-amylase expression. With the exception of HvSPYΔ1-5, the other deletion proteins were partially active in the barley assay, including HvSPYΔ6-9 which lacks TPRs 6, 8 and 9. In Arabidopsis, analysis of seed germination under a range of conditions revealed that 35S:HvSPY increased seed dormancy. Hvspy-2, which lacks parts of the eighth and ninth TPRs, was able to partially complement all aspects of the spy-4 phenotype. In the presence of AtSPY, 35S:HvTPR caused some phenotypes consistent with a decrease in GA signalling, including increased seed sensitivity to paclobutrazol and delayed flowering. These plants also possessed distorted leaf morphology and altered epidermal cell shape. Thus, despite genetic analysis demonstrating that TPRs 6, 8 and 9 are required for regulation of GA signalling, our results suggest that these TPRs are neither absolutely essential nor sufficient for SPY activity.
© 2008 Government Employee.
Keyword Arabidopsis
Gibberellin
Hordeum
Tetratricopeptide repeat (TPR) domain
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown
Additional Notes Published online: 15 November 2008

Document type: Journal Article
Sub-type: Article (original research)
Collection: Australian Institute for Bioengineering and Nanotechnology Publications
 
Versions
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 6 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 7 times in Scopus Article | Citations
Google Scholar Search Google Scholar
Created: Mon, 07 Mar 2011, 11:25:59 EST by Dr Fiona Filardo on behalf of Aust Institute for Bioengineering & Nanotechnology