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J Exp Bot. 2008;59(10):2831-46. doi: 10.1093/jxb/ern144.

Transcription factors relevant to auxin signalling coordinate broad-spectrum metabolic shifts including sulphur metabolism.

Author information

1
Max-Planck-Institut fuer Molekulare Pflanzenphysiologie, Wissenschaftspark Golm, 14424 Potsdam, Germany.

Abstract

A systems approach has previously been used to follow the response behaviour of Arabidopsis thaliana plants upon sulphur limitation. A response network was reconstructed from a time series of transcript and metabolite profiles, integrating complex metabolic and transcript data in order to investigate a potential causal relationship. The resulting scale-free network allowed potential transcriptional regulators of sulphur metabolism to be identified. Here, three sulphur-starvation responsive transcription factors, IAA13, IAA28, and ARF-2 (ARF1-Binding Protein), all of which are related to auxin signalling, were selected for further investigation. IAA28 overexpressing and knock-down lines showed no major morphological changes, whereas IAA13- and ARF1-BP-overexpressing plants grew more slowly than the wild type. Steady-state metabolite levels and expression of pathway-relevant genes were monitored under normal and sulphate-depleted conditions. For all lines, changes in transcript and metabolite levels were observed, yet none of these changes could exclusively be linked to sulphur stress. Instead, up- or down-regulation of the transcription factors caused metabolic changes which in turn affected sulphur metabolism. Auxin-relevant transcription factors are thus part of a complex response pattern to nutrient starvation that serve as coordinators of the metabolic shifts driving sulphur homeostasis rather then as direct effectors of the sulphate assimilation pathway. This study provides the first evidence ever presented that correlates auxin-related transcriptional regulators with primary plant metabolism.

KEYWORDS:

Auxin; sulphur metabolism; systems biology; transcription factors

PMID:
18596113
PMCID:
PMC2486478
DOI:
10.1093/jxb/ern144
[Indexed for MEDLINE]
Free PMC Article

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