Seed germination begins the growth phases of plants and its rate is affected
by plant hormones such as abscisic acid (ABA), gibberellin (GA) and
brassinosteroids (BRs), as well as by environmental factors. The team of
Ji-Hye Jang of Sookmyung Women's University in South Korea searched for
additional reagents that may affect seed germination using the det2-1 and
ga1-3 mutants, which showed reduced seed germination due to their defective
BR- or GA- synthesis, respectively.
The team found that dithiothreitol (DTT) specifically enhanced seed
germination of det2-1 mutant. The team then identified and focused on the
Arabidopsis gene, AtGOLS1, as a differentially expressed gene between the
mutants and those treated with DTT.
AtGOLS1 encodes a galactinol synthase, which is critical for the
oligosaccharide synthesis during seed maturation. The expression of AtGOLS1
was found to decrease when conditions were favorable for seed germination.
Furthermore, seed germination rate was faster in AtGOLS1-knockout mutants
compared with wild type plants.
These results suggest that AtGOLS1 acts as a negative regulator in seed
germination in Arabidopsis.