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Dynamic regulation of PIF 5 by COP 1– SPA complex to optimize photomorphogenesis in Arabidopsis
Author(s) -
Pham Vinh Ngoc,
Kathare Praveen Kumar,
Huq Enamul
Publication year - 2018
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.14074
Subject(s) - photomorphogenesis , ubiquitin ligase , arabidopsis , proteasome , microbiology and biotechnology , arabidopsis thaliana , ubiquitin , biology , transcription factor , etiolation , phytochrome , hypocotyl , cryptochrome , gene , genetics , mutant , botany , biochemistry , red light , circadian clock , enzyme
Summary Light signal provides the spatial and temporal information for plants to adapt to the prevailing environmental conditions. Alterations in light quality and quantity can trigger robust changes in global gene expression. In Arabidopsis thaliana , two groups of key factors regulating those changes in gene expression are CONSTITUTIVE PHOTOMORPHOGENESIS / DEETIOLATED / FUSCA ( COP / DET / FUS ) and a subset of basic helix‐loop‐helix transcription factors called PHYTOCHROME ‐ INTERACTING FACTORS ( PIF s). Recently, rapid progress has been made in characterizing the E3 ubiquitin ligases for the light‐induced degradation of PIF 1, PIF 3 and PIF 4; however, the E3 ligase(s) for PIF 5 remains unknown. Here, we show that the CUL 4 COP 1– SPA complex is necessary for the red light‐induced degradation of PIF 5. Furthermore, COP 1 and SPA proteins stabilize PIF 5 in the dark, but promote the ubiquitination and degradation of PIF 5 in response to red light through the 26S proteasome pathway. Genetic analysis illustrates that overexpression of PIF 5 can partially suppress both cop1‐4 and spaQ seedling de‐etiolation phenotypes under dark and red‐light conditions. In addition, the PIF 5 protein level cycles under both diurnal and constant light conditions, which is also defective in the cop1‐4 and spaQ backgrounds. Both cop1‐4 and spaQ show defects in diurnal growth pattern. Overexpression of PIF 5 partially restores growth defects in cop1‐4 and spaQ under diurnal conditions, suggesting that the COP 1– SPA complex plays an essential role in photoperiodic hypocotyl growth, partly through regulating the PIF 5 level. Taken together, our data illustrate how the CUL 4 COP 1– SPA E3 ligase dynamically controls the PIF 5 level to regulate plant development.