Ectopic overexpression of the transcription factor OsGLK1 induces chloroplast development in non-green rice cells.
Plant Cell Physiol
; 50(11): 1933-49, 2009 Nov.
Article
em En
| MEDLINE
| ID: mdl-19808806
ABSTRACT
For systematic and genome-wide analyses of rice gene functions, we took advantage of the full-length cDNA overexpresser (FOX) gene-hunting system and generated >12 000 independent FOX-rice lines from >25 000 rice calli treated with the rice-FOX Agrobacterium library. We found two FOX-rice lines generating green calli on a callus-inducing medium containing 2,4-D, on which wild-type rice calli became ivory yellow. In both lines, OsGLK1 cDNA encoding a GARP transcription factor was ectopically overexpressed. Using rice expression-microarray and northern blot analyses, we found that a large number of nucleus-encoded genes involved in chloroplast functions were highly expressed and transcripts of plastid-encoded genes, psaA, psbA and rbcL, increased in the OsGLK1-FOX calli. Transmission electron microscopy showed the existence of differentiated chloroplasts with grana stacks in OsGLK1-FOX calli cells. However, in darkness, OsGLK1-FOX calli did not show a green color or develop grana stacks. Furthermore, we found developed chloroplasts in vascular bundle and bundle sheath cells of coleoptiles and leaves from OsGLK1-FOX seedlings. The OsGLK1-FOX calli exhibited high photosynthetic activity and were able to grow on sucrose-depleted media, indicating that developed chloroplasts in OsGLK1-FOX rice calli are functional and active. We also observed that the endogenous OsGLK1 mRNA level increased synchronously with the greening of wild-type calli after transfer to plantlet regeneration medium. These results strongly suggest that OsGLK1 regulates chloroplast development under the control of light and phytohormones, and that it is a key regulator of chloroplast development.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Plantas
/
Oryza
/
Fatores de Transcrição
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Cloroplastos
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Folhas de Planta
Idioma:
En
Revista:
Plant Cell Physiol
Assunto da revista:
BOTANICA
Ano de publicação:
2009
Tipo de documento:
Article
País de afiliação:
Japão