Bimodular auxin response controls organogenesis in Arabidopsis

• DOI: 10.1073/pnas.0915001107
• Publication Date: 2010-01-26T02:54:47Z
• Authors: Ive De Smet; Steffen Lau; Ute Voß; Steffen Vanneste; René Benjamins; Eike H. Rademacher; Alexandra Schlereth; Bert De Rybel; Valya Vassileva; Wim Grunewald; Mirande Naudts; Mitchell P. Levesque; Jasmin S. Ehrismann; Dirk Inzé; Christian Luschnig; Philip N. Benfey; Dolf Weijers; Marc C. E. Van Mo...; Malcolm J. Bennett; Gerd Jürgens; Tom Beeckman
• Keywords: 0301 basic medicine; Arabidopsis; embryo; Receptors, Cell Surface; Protein Serine-Threonine Kinases; Plant Roots; lateral root initiation; 03 medical and health sciences; mediated transformation; Plant Growth Regulators; Gene Expression Regulation, Plant; Cyclins; expression; Morphogenesis; thaliana; gene; transcription factor; 0303 health sciences; Indoleacetic Acids; Arabidopsis Proteins; Reverse Transcriptase Polymerase Chain Reaction; Gene Expression Regulation, Developmental; differentiation; Plants, Genetically Modified; arf19; E2F Transcription Factors; monopteros

Like animals, the mature plant body develops via successive sets of instructions that determine cell fate, patterning, and organogenesis. In the coordination of various developmental programs, several plant hormones play decisive roles, among which auxin is the best-documented hormonal signal. Despite the broad range of processes influenced by auxin, how such a single signaling molecule can be translated into a multitude of distinct responses remains unclear. In Arabidopsis thaliana , lateral root development is a classic example of a developmental process that is controlled by auxin at multiple stages. Therefore, we used lateral root formation as a model system to gain insight into the multifunctionality of auxin. We were able to demonstrate the complementary and sequential action of two discrete auxin response modules, the previously described SOLITARY ROOT/INDOLE-3-ACETIC ACID (IAA)14-AUXIN REPONSE FACTOR (ARF)7-ARF19–dependent lateral root initiation module and the successive BODENLOS/IAA12-MONOPTEROS/ARF5–dependent module, both of which are required for proper organogenesis. The genetic framework in which two successive auxin response modules control early steps of a developmental process adds an extra dimension to the complexity of auxin’s action.