Arabidopsis EMBRYOMAKER encoding an AP2 domain transcription factor plays a key role in developmental change from vegetative to embryonic phase.
Plant Mol Biol
; 73(4-5): 481-92, 2010 Jul.
Article
em En
| MEDLINE
| ID: mdl-20405311
ABSTRACT
Although several types of plant cells retain the competence to enter into embryonic development without fertilization, the molecular mechanism(s) underlying ectopic embryogenesis is largely unknown. To gain insight into this mechanism, in a previous study we identified 136 ESTs specifically expressed in microspore embryogenesis of Brassica napus. Here, we describe the characterization of the Arabidopsis EMBRYOMAKER (EMK) gene, which is homologous to one of the identified Brassica ESTs (BnGemb-58) and encodes an AP2 domain transcription factor. The AtEMK was expressed in developing and mature embryos, but its rapid disappearance occurred during germination. After germination, the expression of AtEMK was found in the root apical meristem and the distal parts of cotyledons. Although a mutant lacking AtEMK exhibited no distinctive defects in the embryo, ectopic expression of AtEMK induced embryo-like structures from cotyledons. The embryo-like structures contained high concentration of lipids, expressed several embryo-specific genes, and could convert into independent plants, indicating that the structures are somatic embryos. In vitro culture, AtEMK enhanced the efficiency of somatic embryogenesis. Furthermore, ectopic expression of AtEMK caused the formation of trichomes on cotyledons, dedifferentiated several tissues into calli, and retarded root development, demonstrating that AtEMK is harmful for the normal development of plants after germination. From these results, we conclude that the AtEMK is a key player to maintain embryonic identity, and the rapid disappearance of AtEMK expression during germination is essential for the developmental transition between the embryonic and vegetative phases in plants.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Sementes
/
Fatores de Transcrição
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Arabidopsis
/
Proteínas de Arabidopsis
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Fator de Transcrição AP-2
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Plant Mol Biol
Assunto da revista:
BIOLOGIA MOLECULAR
/
BOTANICA
Ano de publicação:
2010
Tipo de documento:
Article
País de afiliação:
Japão