The molecular genetics of seed maturation in maize

The maturation phase of seed formation involves coordinated expression of multiple developmental pathways. These processes include abscisic acid regulated responses associated with the arrest of embryo development and induction of anthocyanin synthesis in embryo and aleurone tissues. Studies of the maturation defective vivaparous mutants of maize suggest that one gene, viviparous-1 ( vpl ), regulates both of these pathways in the developing seed. Mutations at vpl reduce the sensitivity of the developing embryo to abscisic acid. In addition, Vpl is required for expression of Cl , a regulatory gene for the anthocyanin pathway. This interaction is consistent with the idea that Vpl and Cl function as part of a regulatory hierarchy controlling seed development. Molecular studies of vpl mutations which separate control of embryo arrest and anthocyanin synthesis suggest that these functions map to discrete domains in the Vpl protein. Therefore, coordinate control of diverse maturation processes may be achieved through expression of a functionally complex regulatory molecule.