Abstract
Most of the higher plants produce leaf-like structures, called bracts, at the base of flowers, while Arabidopsis thaliana does not. However, previous studies showed that cryptic bracts are formed at the base of Arabidopsis flower primordia, suggesting the existence of a mechanism of bract suppression. Recently, BLADE ON PETIOLE 1 (BOP1)/BOP2 and PUCHI have been shown to coordinately function in Arabidopsis bract suppression.
Here, we report MACCHI-BOU 2 (MAB2), AtMed13, as a novel factor involved in bract suppression. Detailed phenotype analysis of mab2 mutants showed that bract primordia developed coincidentally with floral meristem in the inflorescence meristem. To elucidate the relationship between MAB2 and other factors involved in bract suppression, we constructed multiple mutants. Results from the genetic study indicate that MAB2 functions in the same pathway as BOP1/BOP2 and differently from PUCHI in bract suppression. In addition, using a yeast two-hybrid assay, we found that BOP2 could interact with a subunit of CDK8 complex including MAB2/AtMed13. Based on these results, we will present the molecular mechanism of bract suppression in Arabidopsis .
