title: Natural variation of transcriptional auxin response networks in Arabidopsis thaliana.
abstract: Natural variation has been observed for various traits in Arabidopsis thaliana. Here, we investigated natural variation in the context of physiological and transcriptional responses to the phytohormone auxin, a key regulator of plant development. A survey of the general extent of natural variation to auxin stimuli revealed significant physiological variation among 20 genetically diverse natural accessions. Moreover, we observed dramatic variation on the global transcriptome level after induction of auxin responses in seven accessions. Although we detect isolated cases of major-effect polymorphisms, sequencing of signaling genes revealed sequence conservation, making selective pressures that favor functionally different protein variants among accessions unlikely. However, coexpression analyses of a priori defined auxin signaling networks identified variations in the transcriptional equilibrium of signaling components. In agreement with this, cluster analyses of genome-wide expression profiles followed by analyses of a posteriori defined gene networks revealed accession-specific auxin responses. We hypothesize that quantitative distortions in the ratios of interacting signaling components contribute to the detected transcriptional variation, resulting in physiological variation of auxin responses among accessions.
authors.affiliation: Leibniz Institute of Plant Biochemistry, Independent Junior Research Group, 06120 Halle (Saale), Germany.
authors.forename: Carolin
authors.initials: C
authors.lastname: Delker
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Pöschl
authors.forename: Anja
authors.initials: A
authors.lastname: Raschke
authors.forename: Kristian
authors.initials: K
authors.lastname: Ullrich
authors.forename: Stefan
authors.initials: S
authors.lastname: Ettingshausen
authors.forename: Valeska
authors.initials: V
authors.lastname: Hauptmann
authors.forename: Ivo
authors.initials: I
authors.lastname: Grosse
authors.forename: Marcel
authors.initials: M
authors.lastname: Quint
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D007210:Indoleacetic Acids / Q000378:metabolism*; D008969:Molecular Sequence Data; D015398:Signal Transduction; D013045:Species Specificity; D014158:Transcription, Genetic
chemical_list: D007210:Indoleacetic Acids