Reduced gibberellin response affects ethylene biosynthesis and responsiveness in the Arabidopsis gai eto2-1 double mutant.
Ethylene and gibberellins (GAs) control similar developmental processes in plants. The role of ethylene is at least in part to regulate the accumulation of DELLA proteins, key regulators of plant growth, which suppress the GA response. To expand our knowledge of ethylene-GA crosstalk and to reveal how the modulation of the ethylene and GA pathways affects global plant growth, the gibberellin-insensitive (gai), ethylene-overproducing 2-1 (eto2-1) double mutant, which has decreased GA signalling (resulting from gai) and increased ethylene biosynthesis (resulting from eto2-1), was characterized. Both single mutations resulted in reduced elongation growth. The double mutant showed synergistic responses in root and shoot growth, in induction of floral transition, and in inflorescence length, showing that crosstalk between the two pathways occurs in different plant organs throughout development. Furthermore, the altered ethylene-GA interactions affected root-shoot communication, as evidenced by an enhanced shoot:root ratio in the double mutant. When compared with both single mutants and the wild type, double mutants had enhanced content of active GA(4) at both the seedling and the rosette stages, and, unlike the gai mutant, they were sensitive to GA treatment. Finally, it was shown that synergistic responses in the double mutant were not caused by elevated ethylene biosynthesis but that, in the light, enhanced sensitivity to ethylene may, at least in part, be responsible for the observed phenotype.
De Grauwe
Liesbeth
L
Unit Plant Hormone Signaling and Bio-Imaging, Department of Molecular Genetics, Ghent University, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium.
Chaerle
Laury
L
Unit Plant Hormone Signaling and Bio-Imaging, Department of Molecular Genetics, Ghent University, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium.
Dugardeyn
Jasper
J
Unit Plant Hormone Signaling and Bio-Imaging, Department of Molecular Genetics, Ghent University, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium.
Decat
Jan
J
Unit Plant Hormone Signaling and Bio-Imaging, Department of Molecular Genetics, Ghent University, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium.
Rieu
Ivo
I
Crop Performance Improvement Division, Rothamsted Research, Harpenden AL5 2JQ, Herts, UK.
Vriezen
Wim H
WH
Unit Plant Hormone Signaling and Bio-Imaging, Department of Molecular Genetics, Ghent University, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium.
Moritz
Thomas
T
Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 87 Umeå, Sweden.
Beemster
Gerrit T S
GTS
Plant Systems Biology, Flemish Institute of Biology (VIB)/Ghent University, Technologiepark 927, B-9052 Gent, Belgium.
Phillips
Andy L
AL
Crop Performance Improvement Division, Rothamsted Research, Harpenden AL5 2JQ, Herts, UK.
Harberd
Nicholas P
NP
John Innes Centre, Norwich NR4 7UJ, UK.
Hedden
Peter
P
Crop Performance Improvement Division, Rothamsted Research, Harpenden AL5 2JQ, Herts, UK.
Van Der Straeten
Dominique
D
Unit Plant Hormone Signaling and Bio-Imaging, Department of Molecular Genetics, Ghent University, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium.
D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D005030:Ethylenes / Q000096:biosynthesis* / Q000494:pharmacology; D035264:Flowers; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D005875:Gibberellins / Q000378:metabolism*; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism; D036226:Seedlings; D013997:Time Factors
D029681:Arabidopsis Proteins; D005030:Ethylenes; C109555:GAI protein, Arabidopsis; D005875:Gibberellins; C036216:ethylene