Theoretical and experimental evidence indicates that there is no detectable auxin gradient in the angiosperm female gametophyte

Lituiev, D. S., Krohn, N. G., Muller, B., Jackson, D., Hellriegel, B., Dresselhaus, T., Grossniklaus, U. (November 2013) Theoretical and experimental evidence indicates that there is no detectable auxin gradient in the angiosperm female gametophyte. Development, 140 (22). pp. 4544-4553. ISSN 0950-1991

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URL: http://www.ncbi.nlm.nih.gov/pubmed/24194471
DOI: 10.1242/dev.098301

Abstract

The plant life cycle alternates between a diploid sporophytic and a haploid gametophytic generation. The female gametophyte (FG) of flowering plants is typically formed through three syncytial mitoses, followed by cellularisation that forms seven cells belonging to four cell types. The specification of cell fates in the FG has been suggested to depend on positional information provided by an intrinsic auxin concentration gradient. The goal of this study was to develop mathematical models that explain the formation of this gradient in a syncytium. Two factors were proposed to contribute to the maintenance of the auxin gradient in Arabidopsis FGs: polar influx at early stages and localised auxin synthesis at later stages. However, no gradient could be generated using classical, one-dimensional theoretical models under these assumptions. Thus, we tested other hypotheses, including spatial confinement by the large central vacuole, background efflux and localised degradation, and investigated the robustness of cell specification under different parameters and assumptions. None of the models led to the generation of an auxin gradient that was steep enough to allow sufficiently robust patterning. This led us to re-examine the response to an auxin gradient in developing FGs using various auxin reporters, including a novel degron-based reporter system. In agreement with the predictions of our models, auxin responses were not detectable within the FG of Arabidopsis or maize, suggesting that the effects of manipulating auxin production and response on cell fate determination might be indirect.

Item Type: Paper
Uncontrolled Keywords: Arabidopsis Auxin Female gametophyte Gradient Maize Modelling cell-fate arabidopsis-thaliana morphogen gradient indoleacetic-acid pattern-formation embryo sac wild-type egg cell transport maize
Subjects: organism description > plant > Arabidopsis
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification
bioinformatics > genomics and proteomics > genetics & nucleic acid processing
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > gametophyte
CSHL Authors:
Communities: CSHL labs > Jackson lab
Depositing User: Matt Covey
Date: 15 November 2013
Date Deposited: 09 Dec 2013 18:01
Last Modified: 09 Dec 2013 18:01
Related URLs:
URI: http://repository.cshl.edu/id/eprint/28888

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