APETALA2 antagonizes the transcriptional activity of AGAMOUS in regulating floral stem cells in Arabidopsis thaliana.
APETALA2 (AP2) is best known for its function in the outer two floral whorls, where it specifies the identities of sepals and petals by restricting the expression of AGAMOUS (AG) to the inner two whorls in Arabidopsis thaliana. Here, we describe a role of AP2 in promoting the maintenance of floral stem cell fate, not by repressing AG transcription, but by antagonizing AG activity in the center of the flower. We performed a genetic screen with ag-10 plants, which exhibit a weak floral determinacy defect, and isolated a mutant with a strong floral determinacy defect. This mutant was found to harbor another mutation in AG and was named ag-11. We performed a genetic screen in the ag-11 background to isolate mutations that suppress the floral determinacy defect. Two suppressor mutants were found to harbor mutations in AP2. While AG is known to shut down the expression of the stem cell maintenance gene WUSCHEL (WUS) to terminate floral stem cell fate, AP2 promotes the expression of WUS. AP2 does not repress the transcription of AG in the inner two whorls, but instead counteracts AG activity.
Hunan Provincial Key Laboratory of Phytohormones and Growth Development, Hunan Provincial Key Laboratory for Crop Germplasm Innovation and Utilization, Hunan Agricultural University, Changsha, 410128, China.|Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, CA, 92521, USA.
Zhigang
Z
Huang
Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, CA, 92521, USA.|College of Horticulture, Nanjing Agricultural University, No. 1 Weigang, Nanjing, 210095, China.
Ting
T
Shi
State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 200438, China.
Binglian
B
Zheng
Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, CA, 92521, USA.
Rae Eden
RE
Yumul
State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, 050021, China.
Xigang
X
Liu
Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, CA, 92521, USA.|Guangdong Provincial Key Laboratory for Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518060, China.
Chenjiang
C
You
College of Horticulture, Nanjing Agricultural University, No. 1 Weigang, Nanjing, 210095, China.
Zhihong
Z
Gao
Hunan Provincial Key Laboratory of Phytohormones and Growth Development, Hunan Provincial Key Laboratory for Crop Germplasm Innovation and Utilization, Hunan Agricultural University, Changsha, 410128, China.
Langtao
L
Xiao
Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, CA, 92521, USA.|Howard Hughes Medical Institute, University of California, Riverside, CA, 92521, USA.
Xuemei
X
Chen
D026342:AGAMOUS Protein, Arabidopsis / Q000235:genetics*; D000483:Alleles; D017360:Arabidopsis / Q000166:cytology* / Q000235:genetics* / Q000648:ultrastructure; D029681:Arabidopsis Proteins / Q000378:metabolism*; D035264:Flowers / Q000166:cytology* / Q000648:ultrastructure; D018506:Gene Expression Regulation, Plant; D018745:Genome, Plant; D018398:Homeodomain Proteins / Q000378:metabolism*; D018519:Meristem / Q000166:cytology / Q000235:genetics; D008954:Models, Biological; D009154:Mutation; D009687:Nuclear Proteins / Q000378:metabolism*; D010641:Phenotype; D030821:Plants, Genetically Modified; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D014158:Transcription, Genetic
D026342:AGAMOUS Protein, Arabidopsis; C499534:APETALA2 protein, Arabidopsis; D029681:Arabidopsis Proteins; D018398:Homeodomain Proteins; D009687:Nuclear Proteins

AGAMOUS
; 
KNUCKLES
; 
WUSCHEL
; APETALA2; floral determinacy; floral stem cells