The SAC51 family plays a central role in thermospermine responses in arabidopsis

Qingqing Cai, Hiroko Fukushima, Mai Yamamoto, Nami Ishii, Tomoaki Sakamoto, Tetsuya Kurata, Hiroyasu Motose, Taku Takahashi

Research output: Contribution to journalArticle

18 Citations (Scopus)

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 (b-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.

Original languageEnglish
Pages (from-to)1583-1592
Number of pages10
JournalPlant and Cell Physiology
Volume57
Issue number8
DOIs
Publication statusPublished - Aug 1 2016

Fingerprint

Arabidopsis
open reading frames
mutants
xylem
phenotype
Xylem
Open Reading Frames
biosynthesis
Phenotype
null alleles
stop codon
translation (genetics)
Arabidopsis thaliana
thermospermine
mutation
Nonsense Codon
Glucuronidase
DNA
genes
proteins

Keywords

  • Arabidopsis
  • Thermospermine
  • Translation
  • uORF
  • Xylem differentiation

ASJC Scopus subject areas

  • Medicine(all)
  • Physiology
  • Plant Science
  • Cell Biology

Cite this

The SAC51 family plays a central role in thermospermine responses in arabidopsis. / Cai, Qingqing; Fukushima, Hiroko; Yamamoto, Mai; Ishii, Nami; Sakamoto, Tomoaki; Kurata, Tetsuya; Motose, Hiroyasu; Takahashi, Taku.

In: Plant and Cell Physiology, Vol. 57, No. 8, 01.08.2016, p. 1583-1592.

Research output: Contribution to journalArticle

Cai, Q, Fukushima, H, Yamamoto, M, Ishii, N, Sakamoto, T, Kurata, T, Motose, H & Takahashi, T 2016, 'The SAC51 family plays a central role in thermospermine responses in arabidopsis', Plant and Cell Physiology, vol. 57, no. 8, pp. 1583-1592. https://doi.org/10.1093/pcp/pcw113
Cai Q, Fukushima H, Yamamoto M, Ishii N, Sakamoto T, Kurata T et al. The SAC51 family plays a central role in thermospermine responses in arabidopsis. Plant and Cell Physiology. 2016 Aug 1;57(8):1583-1592. https://doi.org/10.1093/pcp/pcw113
Cai, Qingqing ; Fukushima, Hiroko ; Yamamoto, Mai ; Ishii, Nami ; Sakamoto, Tomoaki ; Kurata, Tetsuya ; Motose, Hiroyasu ; Takahashi, Taku. / The SAC51 family plays a central role in thermospermine responses in arabidopsis. In: Plant and Cell Physiology. 2016 ; Vol. 57, No. 8. pp. 1583-1592.
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