Two lily SEPALLATA-like genes cause different effects on floral formation and floral transition in Arabidopsis.
Two AGL2-like MADS-box genes, Lily MADS Box Gene (LMADS) 3 and LMADS4, with extensive homology of LMADS3 to the Arabidopsis SEPALLATA3 were characterized from the lily (Lilium longiflorum). Both LMADS3 and LMADS4 mRNA were detected in the inflorescence meristem, in floral buds of different developmental stages, and in all four whorls of the flower organ. LMADS4 mRNA is also expressed in vegetative leaf and in the inflorescence stem where LMADS3 expression is absent. Transgenic Arabidopsis, which ectopically expresses LMADS3, showed novel phenotypes by significantly reducing plant size, flowering extremely early, and loss of floral determinacy. By contrast, 35S::LMADS4 transgenic plants were morphologically indistinguishable from wild-type plants. The early-flowering phenotype in 35S::LMADS3 transgenic Arabidopsis plants was correlated with the up-regulation of flowering time genes FT, SUPPRESSOR OF OVEREXPRESSION OF CO 1, LUMINIDEPENDENS, and flower meristem identity genes LEAFY and APETALA1. This result was further supported by the ability of 35S::LMADS3 to rescue the late-flowering phenotype in gigantea-1 (gi-1), constans-3 (co-3), and luminidependens-1 but not for ft-1 or fwa-1 mutants. The activation of these flowering time genes is, however, indirect because their expression was unaffected in plants transformed with LMADS3 fused with rat glucocorticoid receptor in the presence of both dexamethasone and cycloheximide.
Tzeng
Tsai-Yu
TY
Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan 40227, Republic of China.
Hsiao
Chih-Chi
CC
Chi
Pei-Ju
PJ
Yang
Chang-Hsien
CH
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D035264:Flowers / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D027762:Lilium / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D026161:MADS Domain Proteins / Q000235:genetics* / Q000378:metabolism; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
D029681:Arabidopsis Proteins; D018398:Homeodomain Proteins; D026161:MADS Domain Proteins; D010940:Plant Proteins; C121158:SEP3 protein, Arabidopsis; D014157:Transcription Factors