title: Identification of transcription factors involved in root apex responses to salt stress in Medicago truncatula.
abstract: The root apex contains meristematic cells that determine root growth and architecture in the soil. Specific transcription factor (TF) genes in this region may integrate endogenous signals and external cues to achieve this. Early changes in transcriptional responses involving TF genes after a salt stress in Medicago truncatula (Mt) roots were analysed using two complementary transcriptomic approaches. Forty-six salt-regulated TF genes were identified using massive quantitative real-time RT-PCR TF profiling in whole roots. In parallel, Mt16K+ microarray analysis revealed 824 genes (including 84 TF sequences) showing significant changes (p < 0.001) in their expression in root apexes after a salt stress. Analysis of salt-stress regulation in root apexes versus whole roots showed that several TF genes have more than 30-fold expression differences including specific members of AP2/EREBP, HD-ZIP, and MYB TF families. Several salt-induced TF genes also respond to other abiotic stresses as osmotic stress, cold and heat, suggesting that they participate in a general stress response. Our work suggests that spatial differences of TF gene regulation by environmental stresses in various root regions may be crucial for the adaptation of their growth to specific soil environments.
authors.affiliation: Institut des Sciences du Végétal, C.N.R.S., 91198, Gif-sur-Yvette, France. gruber@isv.cnrs-gif.fr
authors.forename: Véronique
authors.initials: V
authors.lastname: Gruber
authors.forename: Sandrine
authors.initials: S
authors.lastname: Blanchet
authors.forename: Anouck
authors.initials: A
authors.lastname: Diet
authors.forename: Ons
authors.initials: O
authors.lastname: Zahaf
authors.forename: Adnane
authors.initials: A
authors.lastname: Boualem
authors.forename: Klementina
authors.initials: K
authors.lastname: Kakar
authors.forename: Benoît
authors.initials: B
authors.lastname: Alunni
authors.forename: Michael
authors.initials: M
authors.lastname: Udvardi
authors.forename: Florian
authors.initials: F
authors.lastname: Frugier
authors.forename: Martin
authors.initials: M
authors.lastname: Crespi
mesh_terms: D015870:Gene Expression / Q000187:drug effects; D020869:Gene Expression Profiling; D017343:Genes, Plant; D046913:Medicago truncatula / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D018519:Meristem / Q000187:drug effects / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D009997:Osmotic Pressure; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; D014157:Transcription Factors; D012965:Sodium Chloride