IFEVA   02662
INSTITUTO DE INVESTIGACIONES FISIOLOGICAS Y ECOLOGICAS VINCULADAS A LA AGRICULTURA
Unidad Ejecutora - UE
artículos
Título:
COP1 re-accumulates in the nucleus under shade
Autor/es:
MANUEL PACÍN; MARTINA LEGRIS; JORGE JOSÉ CASAL
Revista:
PLANT JOURNAL
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Lugar: Londres; Año: 2013 p. 1 - 11
ISSN:
0960-7412
Resumen:
Shade-avoider plants typically respond to shade-light signals by increasing the rate of stem growth. CONSTITTUTIVE
PHOTOMORPHOGENESIS 1 (COP1) is an E3 ligase involved in the ubiquitin labelling of proteins
targeted for degradation. In dark-grown seedlings, COP1 accumulates in the nucleus and light exposure
causes COP1 migration to the cytosol. Here, we show that in Arabidopsis thaliana, COP1 accumulates in the
nucleus under natural or simulated shade, despite the presence of far-red light. In plants grown under white
light, the transfer to shade-light conditions triggers an unexpectedly rapid re-accumulation of COP1 in the
nucleus. The partial simulation of shade by lowering either blue or red light levels (maintaining far-red light)
caused COP1 nuclear re-accumulation. Hypocotyl growth of wild-type seedlings is more sensitive to afternoon
shade than to morning shade. A residual response to shade was observed in the cop1 mutant background,
but these seedlings showed inverted sensitivity as they responded to morning shade and not to
afternoon shade. COP1 overexpression exaggerated the wild-type pattern by enhancing afternoon sensitivity
and making morning shade inhibitory of growth. COP1 nuclear re-accumulation also responded more
strongly to afternoon shade than to morning shade. These results are consistent with a signalling role of
COP1 in shade avoidance. We propose a function of COP1 in setting the daily patterns of sensitivity to shade
in the fluctuating light environments of plant canopies.