Genetic complementation of a floral homeotic mutation, apetala3, with an Arabidopsis thaliana gene homologous to DEFICIENS of Antirrhinum majus.

Among the homeotic mutants with altered floral organs, two mutants of Arabidopsis thaliana, apetala3 and pistillata, and two mutants of Antirrhinum majus, deficiens and globosa, have a homeotic conversion of the floral organs in whorl 2 and 3, namely petals to sepals and stamens to carpels. We have isolated a homologue of the DEFICIENS gene from A. thaliana wild type and shown complete complementation of apetala3 mutation by introducing the isolated gene using Agrobacterium-mediated transformation. These results show that the APETALA3 is a homologue of DEFICIENS structurally and functionally. The 5'-upstream region of APETALA3 contains three SRE-like sequence, where MADS box-containing proteins are assumed to bind and regulate expression in tissue- and stage-specific manner.