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BBX28/BBX29, HY5 and BBX30/31 form a feedback loop to fine‐tune photomorphogenic development
Author(s) -
Song Zhaoqing,
Yan Tingting,
Liu Jiujie,
Bian Yeting,
Heng Yueqin,
Lin Fang,
Jiang Yan,
Wang Deng Xing,
Xu Dongqing
Publication year - 2020
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.14929
Subject(s) - photomorphogenesis , hypocotyl , arabidopsis , biology , mutant , regulator , microbiology and biotechnology , function (biology) , downregulation and upregulation , regulation of gene expression , gene , transcriptional regulation , genetics , transcription factor , botany
SUMMARY Light is one of the key environmental cues controlling photomorphogenic development in plants. A group of B‐box (BBX) proteins play critical roles in this developmental process through diverse regulatory mechanisms. In this study we report that BBX29 acts as a negative regulator of light signaling. BBX29 interacts with CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1) and undergoes COP1‐mediated degradation in the dark. Mutant seedlings with loss of BBX29 function show shortened hypocotyls, while transgenic plants overexpressing BBX29 display elongated hypocotyls in the light. Both BBX28 and BBX29 interfere with the binding of ELONGATED HYPOCOTYL 5 (HY5) to the promoters of BBX30 and BBX31 , consequently leading to the upregulation of their transcript levels. BBX30 and BBX31 associate with the promoter regions of BBX28 and BBX29 , which in turn promotes the expression of these genes. Taken together, this study reveals a transcriptional feedback loop consisting of BBX28, BBX29, BBX30, BBX31, and HY5 that serves to fine‐tune photomorphogenesis in response to light in plants.