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Hierarchy of hormone action controlling apical hook development in Arabidopsis
Author(s) -
GallegoBartolomé Javier,
Arana María V.,
Vandenbussche Filip,
Žádníková Petra,
Minguet Eugenio G.,
Guardiola Vicente,
Van Der Straeten Dominique,
Benkova Eva,
Alabadí David,
Blázquez Miguel A.
Publication year - 2011
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2011.04621.x
Subject(s) - hypocotyl , auxin , ethylene , hook , meristem , arabidopsis , microbiology and biotechnology , gibberellin , biology , polarity (international relations) , botany , chemistry , shoot , biophysics , biochemistry , gene , cell , structural engineering , mutant , engineering , catalysis
Summary The apical hook develops in the upper part of the hypocotyl when seeds buried in the soil germinate, and serves to protect cotyledons and the shoot apical meristem from possible damage caused by pushing through the soil. The curvature is formed through differential cell growth that occurs at the two opposite sides of the hypocotyl, and it is established by a gradient of auxin activity and refined by the coordinated action of auxin and ethylene. Here we show that gibberellins (GAs) promote hook development through the transcriptional regulation of several genes of the ethylene and auxin pathways in Arabidopsis. The level of GA activity determines the speed of hook formation and the extent of the curvature during the formation phase independently of ethylene, probably by modulating auxin transport and response through HLS1 , PIN3 , and PIN7 . Moreover, GAs cooperate with ethylene in preventing hook opening, in part through the induction of ethylene production mediated by ACS5/ETO2 and ACS8 .