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Updated: Jun 4, 2026
A Seed Coat Bedding Assay to Genetically Explore In Vitro How the Endosperm Controls Seed Germination in Arabidopsis thaliana
Published on: November 9, 2013
12-oxo-phytodienoic acid accumulation during seed development represses seed germination in Arabidopsis
Anuja Dave1, M Luisa Hernández, Zhesi He
1Centre for Novel Agricultural Products, Department of Biology, University of York, Heslington, York YO105DD, United Kingdom.
Abstract:
Arabidopsis thaliana COMATOSE (CTS) encodes an ABC transporter involved in peroxisomal import of substrates for β-oxidation. Various cts alleles and mutants disrupted in steps of peroxisomal β-oxidation have previously been reported to exhibit a severe block on seed germination. Oxylipin analysis on cts, acyl CoA oxidase1 acyl CoA oxidase2 (acx1 acx2), and keto acyl thiolase2 dry seeds revealed that they contain elevated levels of 12-oxo-phytodienoic acid (OPDA), jasmonic acid (JA), and JA-Ile. Oxylipin and transcriptomic analysis showed that accumulation of these oxylipins occurs during late seed maturation in cts. Analysis of double mutants generated by crossing cts with mutants in the JA biosynthesis pathway indicate that OPDA, rather than JA or JA-Ile, contributes to the block on germination in cts seeds. We found that OPDA was more effective at inhibiting wild-type germination than was JA and that this effect was independent of CORONATINE INSENSITIVE1 but was synergistic with abscisic acid (ABA). Consistent with this, OPDA treatment increased ABA INSENSITIVE5 protein abundance in a manner that parallels the inhibitory effect of OPDA and OPDA+ABA on seed germination. These results demonstrate that OPDA acts along with ABA to regulate seed germination in Arabidopsis.
Insights
Elevated 12-oxo-phytodienoic acid (OPDA) accumulation in Arabidopsis thaliana COMATOSE (CTS) mutants blocks seed germination. OPDA acts with abscisic acid (ABA) to inhibit germination, independent of JA signaling.
Area of Science:
- Plant Biology
- Molecular Biology
- Biochemistry
Background:
- Arabidopsis thaliana COMATOSE (CTS) is an ABC transporter crucial for peroxisomal import of beta-oxidation substrates.
- Mutations in CTS and beta-oxidation pathways cause severe seed germination defects.
- Elevated oxylipins, including 12-oxo-phytodienoic acid (OPDA), jasmonic acid (JA), and JA-Ile, are observed in cts mutant seeds.
Purpose of the Study:
- To investigate the role of oxylipins in the germination block of Arabidopsis cts mutants.
- To determine which specific oxylipin contributes to the germination defect.
- To elucidate the mechanism by which OPDA inhibits seed germination.
Main Methods:
- Oxylipin profiling of wild-type and mutant Arabidopsis seeds (cts, acx1 acx2, keto acyl thiolase2).
- Transcriptomic analysis to identify gene expression changes during seed maturation.
- Genetic analysis using double mutants (cts crossed with JA biosynthesis mutants).
- Seed germination assays with varying oxylipin treatments and hormone combinations.
Main Results:
- cts mutants accumulate high levels of OPDA, JA, and JA-Ile during late seed maturation.
- OPDA, not JA or JA-Ile, is identified as the primary contributor to the germination block in cts seeds.
- OPDA inhibits wild-type seed germination independently of CORONATINE INSENSITIVE1 but synergistically with abscisic acid (ABA).
- OPDA treatment increases ABA INSENSITIVE5 protein levels, correlating with germination inhibition.
Conclusions:
- 12-oxo-phytodienoic acid (OPDA) plays a significant role in inhibiting seed germination in Arabidopsis.
- OPDA acts in concert with abscisic acid (ABA) to regulate seed germination.
- The CTS transporter is indirectly involved in germination control through its impact on OPDA levels.
