title: Leaf-induced gibberellin signaling is essential for internode elongation, cambial activity, and fiber differentiation in tobacco stems.
abstract: The gibberellins (GAs) are a group of endogenous compounds that promote the growth of most plant organs, including stem internodes. We show that in tobacco (Nicotiana tabacum) the presence of leaves is essential for the accumulation of bioactive GAs and their immediate precursors in the stem and consequently for normal stem elongation, cambial proliferation, and xylem fiber differentiation. These processes do not occur in the absence of maturing leaves but can be restored by application of C(19)-GAs, identifying the presence of leaves as a requirement for GA signaling in stems and revealing the fundamental role of GAs in secondary growth regulation. The use of reporter genes for GA activity and GA-directed DELLA protein degradation in Arabidopsis thaliana confirms the presence of a mobile signal from leaves to the stem that induces GA signaling.
authors.affiliation: Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Dayan
authors.forename: Nickolay
authors.initials: N
authors.lastname: Voronin
authors.forename: Fan
authors.initials: F
authors.lastname: Gong
authors.forename: Tai-ping
authors.initials: TP
authors.lastname: Sun
authors.forename: Peter
authors.initials: P
authors.lastname: Hedden
authors.forename: Hillel
authors.initials: H
authors.lastname: Fromm
authors.forename: Roni
authors.initials: R
authors.lastname: Aloni
mesh_terms: D005875:Gibberellins / Q000378:metabolism*; D008969:Molecular Sequence Data; D018515:Plant Leaves / Q000378:metabolism*; D018547:Plant Stems / Q000254:growth & development* / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D014026:Nicotiana / Q000254:growth & development* / Q000378:metabolism*
chemical_list: D005875:Gibberellins