Abstract
Seed dormancy is essential for most plants to control the timing of germination. In Arabidopsis thaliana, PED3 is a single-copy gene that encodes an ATP-binding cassette transporter that is required for peroxisomal fatty acid beta-oxidation. The germination of ped3 mutants is significantly impaired, indicates that PED3 regulates dormancy and germination. A transcriptome analysis revealed that many genes containing the core motif of the ABA responsive element (ABRE) in their promoter regions were up-regulated, and the ABA insensitive 5 (ABI5) transcription factor that binds to some of the ABRE, are abnormally up-regulated in imbibed ped3 seeds. Expression of polygalacturonase inhibiting proteins (PGIPs) is also up-regulated specifically in ped3 after imbibition. By contrast, the ped3abi5 double mutant does not show any of these expression patterns. The results indicate that the abi5 mutation normalizes PGIP expression and rescues the impaired germination phenotype of the ped3 mutant.
