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ID 48760
フルテキストURL
著者
Yoshimoto, Kaori Okayama Univ
Noutoshi, Yoshiteru
Hayashi, Ken-ichiro Okayama Univ Sci
Shirasu, Ken RIKEN
Takahashi, Taku Okayama Univ
Motose, Hiroyasu Okayama Univ
抄録
Thermospermine, a structural isomer of spermine, is produced through the action of ACAULIS5 (ACL5) and suppresses xylem differentiation in Arabidopsis thaliana. To elucidate the molecular basis of the function of thermospermine, we screened chemical libraries for compounds that can modulate xylem differentiation in the acl5 mutant, which is deficient in thermospermine and shows a severe dwarf phenotype associated with excessive proliferation of xylem vessels. We found that the isooctyl ester of a synthetic auxin, 2,4-D, remarkably enhanced xylem vessel differentiation in acl5 seedlings. 2,4-D, 2,4-D analogs and IAA analogs, including 4-chloro IAA (4-Cl-IAA) and IAA ethyl ester, also enhanced xylem vessel formation, while IAA alone had little or no obvious effect on xylem differentiation. These effects of auxin analogs were observed only in the acl5 mutant but not in the wild type, and were suppressed by the anti-auxin, p-chlorophenoxyisobutyric acid (PCIB) and alpha-(phenyl ethyl-2-one)-IAA (PEO-IAA), and also by thermospermine. Furthermore, the suppressor of acaulis51-d (sac51-d) mutation, which causes SAC51 overexpression in the absence of thermospermine and suppresses the dwarf phenotype of acl5, also suppressed the effect of auxin analogs in acl5. These results suggest that the auxin signaling that promotes xylem differentiation is normally limited by SAC51-mediated thermospermine signaling but can be continually stimulated by exogenous auxin analogs in the absence of thermospermine. The opposite action between thermospermine and auxin may fine-tune the timing and spatial pattern of xylem differentiation.
キーワード
ACAULIS5
Arabidopsis thaliana
Auxin
2.4-D
Thermospermine
Xylem differentiation
発行日
2012-04
出版物タイトル
Plant and Cell Physiology
53巻
4号
開始ページ
635
終了ページ
645
ISSN
0032-0781
資料タイプ
学術雑誌論文
オフィシャル URL
http://dx.doi.org/10.1093/pcp/pcs017
言語
English
論文のバージョン
author
査読
有り
DOI
PubMed ID
Web of Sience KeyUT