Control of lateral organ development and flowering time by the Arabidopsis thaliana MADS-box Gene AGAMOUS-LIKE6.
MADS-domain transcription factors play pivotal roles in various developmental processes. The lack of simple loss-of-function phenotypes provides impediments to understand the biological function of some of the MADS-box transcription factors. Here we have characterized the potential role of the Arabidopsis thaliana AGAMOUS-LIKE6 (AGL6) gene by fusing full-length coding sequence with transcriptional activator and repressor domains and suggest a role for AGL6 in lateral organ development and flowering. Upon photoperiodic induction of flowering, AGL6 becomes expressed in abaxial and proximal regions of cauline leaf primordia, as well as the cryptic bracts subtending flowers. In developing flowers, AGL6 is detected in the proximal regions of all floral organs and in developing ovules. Converting AGL6 into a strong activator through fusion to the VP16 domain triggers bract outgrowth, implicating AGL6 in the development of bractless flowers in Arabidopsis. In addition, ectopic reproductive structures form on both bracts and flowers in gAGL6::VP16 transgenic plants, which is dependent on B and C class homeotic genes, but independent of LEAFY. Overexpression of both AGL6 and its transcriptional repressor form, AGL6::EAR, causes precocious flowering and terminal flower formation, suggesting that AGL6 suppresses the function of a floral repressor.
Division of Applied Life Science (BK21 program), Plant Molecular Biology and Biotechnology Research Center and Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660-701, Korea.
Sung C
SC
Koo
Oliver
O
Bracko
Mi S
MS
Park
Rebecca
R
Schwab
Hyun J
HJ
Chun
Kyoung M
KM
Park
Jun S
JS
Seo
Vojislava
V
Grbic
Sureshkumar
S
Balasubramanian
Markus
M
Schmid
François
F
Godard
Dae-Jin
DJ
Yun
Sang Y
SY
Lee
Moo J
MJ
Cho
Detlef
D
Weigel
Min C
MC
Kim
D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D035264:Flowers / Q000254:growth & development*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D026161:MADS Domain Proteins / Q000235:genetics / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D056771:Ovule / Q000254:growth & development / Q000648:ultrastructure; D030821:Plants, Genetically Modified / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics
D029681:Arabidopsis Proteins; D026161:MADS Domain Proteins; D018749:RNA, Plant