Alteration of floral organ identity by over-expression of IbMADS3-1 in tobacco.
The MADS-box genes have been studied mainly in flower development by researching flower homeotic mutants. Most of the MADS-box genes isolated from plants are expressed exclusively in floral tissues, and some of their transcripts have been found in various vegetative tissues. The genes in the STMADS subfamily are important in the development of whole plants including roots, stems, leaves, and the plant vascular system. IbMADS3-1, which is in the STMADS subfamily, and which has been cloned in Ipomoea batatas (L.) Lam., is expressed in all vegetative tissues of the plant, particularly in white fibrous roots. Sequence similarity, besides the spatial and temporal expression patterns, enabled the definition of a novel MADS-box subfamily comprising STMADS16 and the other MADS-box genes in STMADS subfamily expressed specifically in vegetative tissues. Expression of IbMADS3-1 was manifest by the appearance of chlorophyll-containing petals and production of characteristic changes in organ identity carpel structure alterations and sepaloidy of the petals. In reverse transcription-polymerase chain reaction analysis with a number of genes known to be key regulators of floral organ development, the flowering promoter NFL1 was clearly reduced at the RNA level compared with wild type in transgenic line backgrounds. Moreover, NtMADS5 showed slight down-regulation compared with wild-type plants in transgenic lines. These results suggest that IbMADS3-1 could be a repressor of NFL1 located upstream of NtMADS5. IbMADS3-1 ectopic expression is suggested as a possible means during vegetative development by which the IbMADS3-1 gene may interfere with the floral developmental pathway.
Shin
Mi-Rae
MR
Department of Environmental Horticulture, University of Seoul, Seoul, 130-743, Korea.
Seo
Sang-Gyu
SG
Kim
Ji-Seoung
JS
Joen
Seo-Bum
SB
Kang
Seung-Won
SW
Lee
Gung-Pyo
GP
Kwon
Suk-Yoon
SY
Kim
Sun-Hyung
SH
D000595:Amino Acid Sequence; D001483:Base Sequence; D035264:Flowers / Q000235:genetics / Q000254:growth & development*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D027723:Ipomoea batatas / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D026161:MADS Domain Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
D026161:MADS Domain Proteins; D010940:Plant Proteins