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TheSAC51Family Plays a Central Role in Thermospermine Responses in Arabidopsis
- Source :
- Plant and Cell Physiology. 57:1583-1592
- Publication Year :
- 2016
- Publisher :
- Oxford University Press (OUP), 2016.
-
Abstract
- The acaulis5 (acl5) mutant of Arabidopsis thaliana is defective in the biosynthesis of thermospermine and shows a dwarf phenotype associated with excess xylem differentiation. SAC51 was identified from a dominant suppressor of acl5, sac51-d, and encodes a basic helix-loop-helix protein. The sac51-d mutant has a premature termination codon in an upstream open reading frame (uORF) that is conserved among all four members of the SAC51 family, SAC51 and SACL1-SACL3 This suggests that thermospermine cancels the inhibitory effect of the uORF in main ORF translation. Another suppressor, sac57-d, has a mutation in the conserved uORF of SACL3 To define further the function of the SAC51 family in the thermospermine response, we analyzed T-DNA insertion mutants of each gene. Although sacl1-1 may not be a null allele, the quadruple mutant showed a semi-dwarf phenotype but with an increased level of thermospermine and decreased sensitivity to exogenous thermospermine that normally represses xylem differentiation. The sac51-1 sacl3-1 double mutant was also insensitive to thermospermine. These results suggest that SAC51 and SACL3 play a key role in thermospermine-dependent negative control of thermospermine biosynthesis and xylem differentiation. Using 5' leader-GUS (β-glucuronidase) fusion constructs, however, we detected a significant enhancement of the GUS activity by thermospermine only in SAC51 and SACL1 constructs. Furthermore, while acl5-1 sac51-1 showed the acl5 dwarf phenotype, acl5-1 sacl3-1 exhibited an extremely tiny-plant phenotype. These results suggest a complex regulatory network for the thermospermine response in which SAC51 and SACL3 function in parallel pathways.
- Subjects :
- 0301 basic medicine
Translation
Physiology
Mutant
Arabidopsis
Plant Science
medicine.disease_cause
Models, Biological
Open Reading Frames
03 medical and health sciences
Gene Expression Regulation, Plant
Genes, Reporter
Xylem
Upstream open reading frame
Basic Helix-Loop-Helix Transcription Factors
medicine
Arabidopsis thaliana
Amino Acid Sequence
Gene
Genetics
Mutation
biology
Arabidopsis Proteins
food and beverages
Cell Biology
General Medicine
biology.organism_classification
Null allele
Phenotype
Thermospermine
Mutagenesis, Insertional
Xylem differentiation
030104 developmental biology
Seedlings
Spermine
Sequence Alignment
uORF
Subjects
Details
- ISSN :
- 14719053 and 00320781
- Volume :
- 57
- Database :
- OpenAIRE
- Journal :
- Plant and Cell Physiology
- Accession number :
- edsair.doi.dedup.....7c7d52fc66377877c144223e11c6512b