title: Components acting downstream of short day perception regulate differential cessation of cambial activity and associated responses in early and late clones of hybrid poplar.
abstract: Short days (SDs) in autumn induce growth cessation, bud set, cold acclimation, and dormancy in trees of boreal and temperate forests, and these responses occur earlier in northern than in southern genotypes. Nevertheless, we know little about whether this variation results from differential perception of SDs or differential downstream responses to the SD signal or a combination of the two. We compared global patterns of SD-regulated gene expression in the stems of hybrid poplar (Populus trichocarpa × Populus deltoides) clones that differ in their SD-induced growth cessation in order to address this question. The timing of cessation of cambial cell division caused by SDs differed between the clones and was coincident with the change in the pattern of expression of the auxin-regulated genes. The clones also differed in the timing of their SD-regulated changes in the transcript abundance of genes associated with cold tolerance, starch breakdown, and storage protein accumulation. By analyzing the expression of homologs of FLOWERING LOCUS T, we demonstrated that the clones differed little in their perception of SDs under the growth conditions applied but differed substantially in the downstream responses manifested in the timing and magnitude of gene expression after SD treatment. These results demonstrate the existence of factors that act downstream of SD perception and can contribute to variation in SD-regulated adaptive photoperiodic responses in trees.
authors.affiliation: Department of Plant Physiology and Forest Genetics, Swedish University of Agricultural Sciences, Umea, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Resman
authors.forename: Glenn
authors.initials: G
authors.lastname: Howe
authors.forename: David
authors.initials: D
authors.lastname: Jonsen
authors.forename: Madeleine
authors.initials: M
authors.lastname: Englund
authors.forename: Nathalie
authors.initials: N
authors.lastname: Druart
authors.forename: Jarmo
authors.initials: J
authors.lastname: Schrader
authors.forename: Henrik
authors.initials: H
authors.lastname: Antti
authors.forename: Jeff
authors.initials: J
authors.lastname: Skinner
authors.forename: Andreas
authors.initials: A
authors.lastname: Sjödin
authors.forename: Tony
authors.initials: T
authors.lastname: Chen
authors.forename: Rishikesh P
authors.initials: RP
authors.lastname: Bhalerao
mesh_terms: D058506:Cambium / Q000166:cytology / Q000254:growth & development*; D002455:Cell Division; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D020411:Oligonucleotide Array Sequence Analysis; D017440:Photoperiod; D032107:Populus / Q000235:genetics / Q000254:growth & development*; D018749:RNA, Plant / Q000235:genetics; D014197:Trees / Q000235:genetics / Q000254:growth & development
chemical_list: D018749:RNA, Plant