IFEVA   02662
INSTITUTO DE INVESTIGACIONES FISIOLOGICAS Y ECOLOGICAS VINCULADAS A LA AGRICULTURA
Unidad Ejecutora - UE
artículos
Título:
Blue rhythms between GIGANTEA and phytochromes
Autor/es:
MARÍA CREPY; MARCELO J. YANOVSKY; JORGE J. CASAL
Revista:
Plant Signaling & Behavior
Referencias:
Año: 2007 vol. 2 p. 530 - 532
ISSN:
1559-2316
Resumen:
GIGANTEA (GI) is involved in the promotion of
flowering by long days, in light input to the circadian clock, and in seedling de-etiolation
under continuous red light or blue light but not under continuous far-red light
(FR). Since red-light effects are mediated largely by phytochrome B and those
of FR by phytochrome A (phyA), GI was considered not to affect phyA signaling.
However, recent observations using brief FR pulses indicate that GI does affect
the very-low-fluence response (VLFR) and not the high-irradiance response (HIR)
pathway of phyA. Seed germination, seedling de-etiolation and gene expression
showed rhythmic sensitivity to FR pulses. GI affected the magnitude but not the
rhythmic pattern of the responses, indicating that GI regulation of phyA
signaling does not derive from its effects on the clock. Here we show that despite
de above divergence between VLFR and HIR, both pathways require the bZip
transcription factor HY5. Furthermore, the blue-light phenotype of gi is not mediated by phyA, indicating a
role of GI in the control of cryptochrome signaling. These findings illustrate
features of plant signaling networks.