The modified ABC model explains the development of the petaloid perianth of Agapanthus praecox ssp. orientalis (Agapanthaceae) flowers

• DOI: 10.1007/s11103-005-5218-z
• Publication Date: 2005-07-14T19:37:59Z
• Authors: Toru Nakamura; Tatsuya Fukuda; Masaru Nakano; Mitsuyasu Hasebe; Toshiaki Kameya; Akira Kanno
• Keywords: Homeodomain Proteins; 0303 health sciences; DNA, Complementary; Genotype; Models, Genetic; Molecular Sequence Data; Arabidopsis; Gene Expression Regulation, Developmental; MADS Domain Proteins; Flowers; Plants, Genetically Modified; DEFICIENS Protein; Magnoliopsida; 03 medical and health sciences; Phenotype; Gene Expression Regulation, Plant; Amino Acid Sequence; RNA, Messenger; Cloning, Molecular; In Situ Hybridization; Phylogeny; Plant Proteins

The class B genes, which belong to the MADS-box gene family, play important roles in regulating the development of petals and stamens in flowering plants. To understand the molecular mechanisms of floral development in Agapanthus praecox ssp. orientalis (Agapanthaceae), we isolated and characterized the homologs of the Antirrhinum majus genes GLOBOSA and DEFICIENS in this plant. These were designated as ApGLO and ApDEF, respectively. ApGLO and ApDEF contain open reading frames that encode deduced protein with 210 and 214 amino acid residues, respectively. Phylogenetic analysis indicated that ApGLO and ApDEF belong to the monocot class B gene family. In situ hybridization experiments revealed that hybridization signals of ApGLO and ApDEF were observed in whorl 1 as well as in whorls 2 and 3. Moreover, the flowers of transgenic Arabidopsis plants that ectopically expressed ApGLO formed petal-like organs in whorl 1. These observations indicate that the flower developmental mechanism of Agapanthus follows the modified ABC model.