Premium
COP 1 re‐accumulates in the nucleus under shade
Author(s) -
Pacín Manuel,
Legris Martina,
Casal Jorge J.
Publication year - 2013
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12226
Subject(s) - photomorphogenesis , shade avoidance , hypocotyl , phytochrome , biology , shade tolerance , botany , darkness , arabidopsis thaliana , nucleus , blue light , ubiquitin ligase , arabidopsis , horticulture , mutant , red light , microbiology and biotechnology , ubiquitin , genetics , gene , physics , canopy , optics
Summary Shade‐avoider plants typically respond to shade‐light signals by increasing the rate of stem growth. CONSTITTUTIVE PHOTOMORPHOGENESIS 1 ( COP 1) is an E 3 ligase involved in the ubiquitin labelling of proteins targeted for degradation. In dark‐grown seedlings, COP 1 accumulates in the nucleus and light exposure causes COP 1 migration to the cytosol. Here, we show that in A rabidopsis thaliana , COP 1 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 COP 1 in the nucleus. The partial simulation of shade by lowering either blue or red light levels (maintaining far‐red light) caused COP 1 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. COP 1 overexpression exaggerated the wild‐type pattern by enhancing afternoon sensitivity and making morning shade inhibitory of growth. COP 1 nuclear re‐accumulation also responded more strongly to afternoon shade than to morning shade. These results are consistent with a signalling role of COP 1 in shade avoidance. We propose a function of COP 1 in setting the daily patterns of sensitivity to shade in the fluctuating light environments of plant canopies.