Genetic and molecular regulation by DELLA proteins of trichome development in Arabidopsis.
Gibberellins (GA) are known to influence phase change in Arabidopsis (Arabidopsis thaliana) as well as the development of trichomes, which are faithful epidermal markers of shoot maturation. They modulate these developmental programs in part by antagonizing DELLA repressors of growth, GIBBERELLIC ACID INSENSITIVE (GAI) and REPRESSOR OF ga1-3 (RGA). In this study, we have probed the relative roles played by RGA, GAI, and two homologs, RGA-LIKE1 (RGL1) and RGL2, in these processes and investigated molecular mechanisms through which they influence epidermal differentiation. We found that the DELLAs act collectively to regulate trichome initiation on all aerial organs and that the onset of their activity is accompanied by the repression of most genes known to regulate trichome production. These effects are consistent with the results of genetic analysis, which conclusively place theses genes downstream of the DELLAs. We find that repression of trichome regulatory genes is rapid, but involves an indirect, rather than a direct, molecular mechanism, which requires de novo protein synthesis. DELLA activity also influences postinitiation events and we show that GAI is a major repressor of trichome branching, a role in which it is antagonized by RGL1 and RGL2. Finally, we report that, in contrast to most other effects, the repression by GA applications of flower trichome initiation is not dependent on RGA, GAI, RGL1, or RGL2. In summary, our data show that DELLA proteins are central to trichome development in Arabidopsis and that their effect can be largely explained by their transcriptional influence on trichome initiation activators.
Gan
Yinbo
Y
Centre for Novel Agricultural Products, Department of Biology, University of York, York YO10 5YW, United Kingdom.
Yu
Hao
H
Peng
Jinrong
J
Broun
Pierre
P
D017360:Arabidopsis / Q000166:cytology / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D035264:Flowers; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D005810:Multigene Family; D009154:Mutation; D018515:Plant Leaves / Q000166:cytology* / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism
D029681:Arabidopsis Proteins
Plant Physiol. 1997 Apr;113(4):1051-8
9112768
Plant Physiol. 2006 Oct;142(2):509-25
16920880
Genetics. 2000 Nov;156(3):1349-62
11063707
Plant Cell. 2002 Jan;14(1):57-70
11826299
Development. 2001 May;128(9):1539-46
11290293
Genetics. 2001 Oct;159(2):777-85
11606552
Plant Cell. 2002 Dec;14(12):3191-200
12468736
Int Rev Cytol. 1999;186:147-78
9770299
Plant J. 2005 Oct;44(1):88-99
16167898
Genetics. 1999 May;152(1):461-76
10224275
Plant Cell. 1999 Jul;11(7):1337-50
10402433
Plant Cell. 2005 Jan;17(1):92-102
15608330
Plant Cell. 2004 Jun;16(6):1392-405
15155881
Development. 2007 Jun;134(11):2073-81
17507408
Plant Cell. 1998 Feb;10(2):155-69
9490740
Development. 1997 Feb;124(3):645-54
9043079
Plant Cell. 2003 May;15(5):1120-30
12724538
Plant Physiol. 1998 Jun;117(2):375-83
9625690
Plant Cell. 2001 Jul;13(7):1555-66
11449051
Plant Cell. 1994 Aug;6(8):1065-1076
12244266
Plant Physiol. 1992 Sep;100(1):403-8
16652976
Plant Physiol. 1996 Aug;111(4):1321-8
8756507
Plant Physiol. 2004 Jun;135(2):1008-19
15173565
Planta. 2005 Nov;222(4):730-42
16021502
Development. 2004 Mar;131(5):1055-64
14973286
Science. 2003 Mar 21;299(5614):1896-8
12649483
Genetics. 2001 Oct;159(2):767-76
11606551
Development. 2003 Oct;130(20):4859-69
12917293
Plant Cell. 2004 Jun;16(6):1406-18
15161962
Genes Dev. 2002 Mar 1;16(5):646-58
11877383
Science. 2003 Mar 21;299(5614):1853-4
12649470
Proc Natl Acad Sci U S A. 2004 May 18;101(20):7827-32
15128937
Science. 1999 Jul 23;285(5427):582-4
10417387
Nature. 2005 Sep 29;437(7059):693-8
16193045
Planta. 2005 Dec;223(1):105-13
16034591
Genetics. 1997 Jul;146(3):1087-99
9215910
Plant Cell. 2002 Jan;14(1):87-100
11826301
Plant Cell. 2006 Feb;18(2):278-82
16452510
Plant Cell. 2006 Jun;18(6):1383-95
16679458
Genes Dev. 1997 Dec 1;11(23):3194-205
9389651