ID 55380
FullText URL
Thumnail Fig.pdf 4.29 MB
Author
Cai, Qingqing Graduate School of Natural Science and Technology, Okayama University
Fukushima, Hiroko Graduate School of Natural Science and Technology, Okayama University
Yamamoto, Mai Graduate School of Natural Science and Technology, Okayama University
Ishii, Nami Graduate School of Natural Science and Technology, Okayama University
Sakamoto, Tomoaki Graduate School of Biological Sciences, Nara Institute of Science and Technology
Kurata, Tetsuya Graduate School of Biological Sciences, Nara Institute of Science and Technology
Motose, Hiroyasu Graduate School of Natural Science and Technology, Okayama University
Takahashi, Taku Graduate School of Natural Science and Technology, Okayama University
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.
Keywords
Arabidopsis
Thermospermine
Translation
Xylem differentiation
uORF
Note
This is an Accepted Manuscript of an article published by Oxford University Press
Published Date
2016-08
Publication Title
Plant and Cell Physiology
Volume
volume57
Issue
issue8
Publisher
Japanese Society of Plant Physiologists
Start Page
1583
End Page
1592
ISSN
0032-0781
NCID
AA0077511X
Content Type
Journal Article
language
英語
OAI-PMH Set
岡山大学
Copyright Holders
http://creativecommons.org/licenses/by-nc-nd/4.0/
File Version
author
PubMed ID
DOI
Web of Sience KeyUT
Related Url
https://doi.org/10.1093/pcp/pcw113