Arabidopsis SMO2 regulates seed germination and ABA response.

Arabidopsis SMALL ORGAN2 (SMO2) encodes a functional homologue of yeast TRM112, and disruption of SMO2 results in a defect in progression of cell division and organ growth. Here, we show that SMO2 mediates the abscisic acid (ABA) response during seed germination. smo2 exhibits an obvious delay of seed germination and is hypersensitive to abscisic acid (ABA), while transgenic seeds overexpressing SMO2 are hyposensitive to ABA. Given that SMO2 is required for proper cell division in root apex, our observation suggests that SMO2-regulated progression of cell division is involved in ABA response during seed germination.