title: Activity-dormancy transition in the cambial meristem involves stage-specific modulation of auxin response in hybrid aspen.
abstract: The molecular basis of short-day-induced growth cessation and dormancy in the meristems of perennial plants (e.g., forest trees growing in temperate and high-latitude regions) is poorly understood. Using global transcript profiling, we show distinct stage-specific alterations in auxin responsiveness of the transcriptome in the stem tissues during short-day-induced growth cessation and both the transition to and establishment of dormancy in the cambial meristem of hybrid aspen trees. This stage-specific modulation of auxin signaling appears to be controlled via distinct mechanisms. Whereas the induction of growth cessation in the cambium could involve induction of repressor auxin response factors (ARFs) and down-regulation of activator ARFs, dormancy is associated with perturbation of the activity of the SKP-Cullin-F-box(TIR) (SCF(TIR)) complex, leading to potential stabilization of repressor auxin (AUX)/indole-3-acetic acid (IAA) proteins. Although the role of hormones, such as abscisic acid (ABA) and gibberellic acid (GA), in growth cessation and dormancy is well established, our data now implicate auxin in this process. Importantly, in contrast to most developmental processes in which regulation by auxin involves changes in cellular auxin contents, day-length-regulated induction of cambial growth cessation and dormancy involves changes in auxin responses rather than auxin content.
authors.affiliation: Department of Forest Genetics and Plant Physiology, Umea Plant Science Centre, Swedish University of Agricultural Sciences, SE-90183 Umea, Sweden.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Baba
authors.forename: Anna
authors.initials: A
authors.lastname: Karlberg
authors.forename: Julien
authors.initials: J
authors.lastname: Schmidt
authors.forename: Jarmo
authors.initials: J
authors.lastname: Schrader
authors.forename: Torgeir R
authors.initials: TR
authors.lastname: Hvidsten
authors.forename: Laszlo
authors.initials: L
authors.lastname: Bako
authors.forename: Rishikesh P
authors.initials: RP
authors.lastname: Bhalerao
mesh_terms: D058506:Cambium / Q000254:growth & development*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids; D018519:Meristem / Q000254:growth & development*; D010937:Plant Growth Regulators / Q000502:physiology*; D014197:Trees / Q000502:physiology*
chemical_list: D007210:Indoleacetic Acids; D010937:Plant Growth Regulators