Functional analysis of three lily (Lilium longiflorum) APETALA1-like MADS box genes in regulating floral transition and formation.
Three cDNAs showing a high degree of homology to the SQUA subfamily of MADS box genes were isolated and characterized from the lily (Lilium longiflorum). Lily MADS Box Gene 5 (LMADS5) showed high sequence identity to oil palm (Elaeis guineensis) SQUAMOSA3 (EgSQUA3). LMADS6 is closely related to LMADS5 whereas LMADS7 is more related to DOMADS2, an orchid (Dendrobium) gene in the SQUA subfamily. The expression pattern for these three genes was similar and their RNAs were detected in vegetative stem and inflorescence meristem. LMADS5 and 6 were highly expressed in vegetative leaves and carpel, whereas LMADS7 expression was absent. Ectopic expression of LMADS5, 6 or 7 in transgenic Arabidopsis plants showed novel phenotypes by flowering early and producing terminal flowers. Homeotic conversions of sepals to carpelloid structures and of petal to stamen-like structures were also observed in 35S::LMADS5, 6 or 7 flowers. Ectopic expression of LMADS6 or LMADS7 was able to complement the ap1 flower defect in transgenic Arabidopsis ap1 mutant plants. These results strongly indicated that the function of these three lily genes was involved in flower formation as well as in floral induction. Furthermore, the ability of lily LMADS6 and 7 to complement the Arabidopsis ap1 mutant provided further evidence to show that the conserved motifs (paleoAP1 or euAP1) in the C-terminus of the SQUA/AP1 subfamily of MADS box genes is not strictly necessary for their function.
Chen
Ming-Kun
MK
Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan 40227, ROC.
Lin
I-Chun
IC
Yang
Chang-Hsien
CH
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics; D018076:DNA, Complementary / Q000302:isolation & purification; D019143:Evolution, Molecular; D035264:Flowers / Q000235:genetics* / Q000254:growth & development*; D018506:Gene Expression Regulation, Plant; D005801:Genes, Homeobox; D017343:Genes, Plant; D027762:Lilium / Q000235:genetics* / Q000254:growth & development; D026161:MADS Domain Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D010802:Phylogeny; D030821:Plants, Genetically Modified; D016415:Sequence Alignment
D018076:DNA, Complementary; D026161:MADS Domain Proteins