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A CRY – BIC negative‐feedback circuitry regulating blue light sensitivity of Arabidopsis
Author(s) -
Wang Xu,
Wang Qin,
Han YunJeong,
Liu Qing,
Gu Lianfeng,
Yang Zhaohe,
Su Jun,
Liu Bobin,
Zuo Zecheng,
He Wenjin,
Wang Jian,
Liu Bin,
Matsui Minami,
Kim JeongIl,
Oka Yoshito,
Lin Chentao
Publication year - 2017
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.13664
Subject(s) - cryptochrome , arabidopsis , hypocotyl , phytochrome , microbiology and biotechnology , transcription factor , biology , blue light , transcription (linguistics) , chemistry , gene , botany , biochemistry , mutant , circadian clock , red light , materials science , optoelectronics , linguistics , philosophy
Summary Cryptochromes are blue light receptors that regulate various light responses in plants. Arabidopsis cryptochrome 1 ( CRY 1) and cryptochrome 2 ( CRY 2) mediate blue light inhibition of hypocotyl elongation and long‐day ( LD ) promotion of floral initiation. It has been reported recently that two negative regulators of Arabidopsis cryptochromes, Blue light Inhibitors of Cryptochromes 1 and 2 ( BIC 1 and BIC 2), inhibit cryptochrome function by blocking blue light‐dependent cryptochrome dimerization. However, it remained unclear how cryptochromes regulate the BIC gene activity. Here we show that cryptochromes mediate light activation of transcription of the BIC genes, by suppressing the activity of CONSTITUTIVE PHOTOMORPHOGENIC 1 ( COP 1), resulting in activation of the transcription activator ELONGATED HYPOCOTYL 5 ( HY 5) that is associated with chromatins of the BIC promoters. These results demonstrate a CRY – BIC negative‐feedback circuitry that regulates the activity of each other. Surprisingly, phytochromes also mediate light activation of BIC transcription, suggesting a novel photoreceptor co‐action mechanism to sustain blue light sensitivity of plants under the broad spectra of solar radiation in nature.