title: The zinc finger protein PtaZFP2 negatively controls stem growth and gene expression responsiveness to external mechanical loads in poplar.
abstract: Mechanical cues are essential signals regulating plant growth and development. In response to wind, trees develop a thigmomorphogenetic response characterized by a reduction in longitudinal growth, an increase in diameter growth, and changes in mechanical properties. The molecular mechanisms behind these processes are poorly understood. In poplar, PtaZFP2, a C2H2 transcription factor, is rapidly up-regulated after stem bending. To investigate the function of PtaZFP2, we analyzed PtaZFP2-overexpressing poplars (Populus tremula × Populus alba). To unravel the genes downstream PtaZFP2, a transcriptomic analysis was performed. PtaZFP2-overexpressing poplars showed longitudinal and cambial growth reductions together with an increase in the tangent and hardening plastic moduli. The regulation level of mechanoresponsive genes was much weaker after stem bending in PtaZFP2-overexpressing poplars than in wild-type plants, showing that PtaZFP2 negatively modulates plant responsiveness to mechanical stimulation. Microarray analysis revealed a high proportion of down-regulated genes in PtaZFP2-overexpressing poplars. Among these genes, several were also shown to be regulated by mechanical stimulation. Our results confirmed the important role of PtaZFP2 during plant acclimation to mechanical load, in particular through a negative control of plant molecular responsiveness. This desensitization process could modulate the amplitude and duration of the plant response during recurrent stimuli.
authors.affiliation: Clermont Université, Université Blaise Pascal, UMR547 PIAF, BP 10448, F-63000, Clermont-Ferrand, France; INRA, UMR547 PIAF, F-63100, Clermont-Ferrand, France.
authors.forename: Ludovic
authors.initials: L
authors.lastname: Martin
authors.forename: Mélanie
authors.initials: M
authors.lastname: Decourteix
authors.forename: Eric
authors.initials: E
authors.lastname: Badel
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Huguet
authors.forename: Bruno
authors.initials: B
authors.lastname: Moulia
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Julien
authors.forename: Nathalie
authors.initials: N
authors.lastname: Leblanc-Fournier
mesh_terms: D000064:Acclimatization / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D010940:Plant Proteins / Q000235:genetics / Q000502:physiology*; D018547:Plant Stems / Q000254:growth & development*; D030821:Plants, Genetically Modified / Q000254:growth & development; D032107:Populus / Q000235:genetics* / Q000254:growth & development; D013314:Stress, Mechanical; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*; D059467:Transcriptome; D014197:Trees / Q000235:genetics / Q000254:growth & development; D014919:Wind; D016335:Zinc Fingers
chemical_list: D010940:Plant Proteins; D014157:Transcription Factors
keywords: abiotic stimulus; acclimation; mechanical load; poplar (Populus tremula × P. alba); thigmomorphogenesis; tree; wood; zinc finger transcription factor