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J Exp Bot. 2019 Apr 5. pii: erz146. doi: 10.1093/jxb/erz146. [Epub ahead of print]

Aethionema arabicum: a novel model plant to study the light control of seed germination.

Author information

1
Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna BioCenter (VBC), Dr. Bohr-Gasse, Vienna, Austria.
2
School of Biological Sciences, Plant Molecular Science and Centre for Systems and Synthetic Biology, Royal Holloway University of London, Egham, Surrey, United Kingdom.
3
Plant Cell Biology, Faculty of Biology, University of Marburg, Karl-von-Frisch-Str., Marburg, Germany.
4
Laboratory of Growth Regulators, The Czech Academy of Sciences, Institute of Experimental Botany & Palacký University, Šlechtitelů, CZ Olomouc, Czech Republic.

Abstract

Timing of seed germination is crucial for seed plants and coordinated by internal and external cues, reflecting adaptations to different habitats. Physiological and molecular studies with lettuce and Arabidopsis thaliana have documented a strict requirement for light to initiate germination and identified many receptors, signalling cascades, and hormonal control elements. In contrast, seed germination of several other plants is inhibited by light, but the molecular basis of this converse response is unknown. We describe Aethionema arabicum (Brassicaceae) as a suitable model plant to investigate the mechanism of germination inhibition by light, as it comprises accessions with natural variation between light-sensitive and light-neutral responses. Inhibition occurs in red, blue or far-red light and increases with light intensity and duration. Gibberellins and abscisic acid are involved in the control of germination as in Arabidopsis, but transcriptome comparisons of light- and dark-exposed Aethionema arabicum seeds revealed that expression of genes for key regulators upon light exposure undergo converse changes, resulting in antipodal hormone regulation. This illustrates that similar modular components of a pathway in light-inhibited, light-neutral and light requiring germination among the Brassicaceae have been assembled by evolution to produce divergent pathways, likely as adaptive traits.

KEYWORDS:

Aethionema arabicum ; light inhibition; model plant; natural variation; seed germination; transcriptional regulation

PMID:
30949700
DOI:
10.1093/jxb/erz146

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