Phosphorylation of FAR-RED ELONGATED HYPOCOTYL1 Is a Key Mechanism Defining Signaling Dynamics of Phytochrome A under Red and Far-Red Light in <i>Arabidopsis</i>

Chen, Fang; Shi, Xiarong; Chen, Liang; Dai, Mingqiu; Zhang, Zhou; Shen, Yulong; Li, Jigang; Li, Gang; Wei, Ning; Deng, Xing Wang

doi:10.1105/tpc.112.097733

Cited by 38 publications

(62 citation statements)

References 46 publications

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“…S2A). This result is consistent with the observation that FHY1 accumulates in the nucleus upon FR irradiation (8).…”

Section: Fhy1 and Phya Coordinately Regulate Their Common Direct Targetsupporting

confidence: 82%

“…S1B). Their positions were consistent with that of G-boxes, DNA elements that are critical for phyA-dependent CHS and NAC019 expression (8,9).…”

Section: Resultssupporting

confidence: 52%

“…To determine whether phyA and FHY1 associate with the same genes upon FR irradiation, 4-d-old etiolated 35S: GFP-FHY1 fhy1-1 transgenic seedlings (12) were exposed to 3 h FR, the same conditions used for detection of the phyA-associated genes (9). The treated plants were used for ChIP-seq analysis with an anti-FHY1 antibody that exhibits high specificity in the detection of FR-induced FHY1-association events (8). FHY1-associated DNA samples from three distinct biological replicates and an input DNA sample (as a negative control) were subjected to high-throughput Solexa (Illumina) sequencing.…”

Section: Resultsmentioning

confidence: 99%

“…This event inhibits the nuclear translocation of FHY1 and consequently prevents further nuclear accumulation of phyA. Under FR, however, persistent phyA nuclear translocation is observed with nonphosphorylated FHY1 (8); second, the nucleo-cytoplasmic shuttling of FHY1/FHL is also reduced under R owing to the low dissociation rate of the Pfr-FHY1/ FHL complex. The FR-driven phyA conversion to its Pr form benefits the recycling of FHY1/FHL for continuous phyA nuclear transportation (4).…”

mentioning

confidence: 95%

“…It was recently demonstrated that the nuclear phyA-FHY1 complex is recruited to the promoter regions of FR-responsive genes CHS (chalcone synthase) and NAC019 [no apical meristem (NAM), Arabidopsis transcription activation factor (ATAF), cup-shaped cotyledon (CUC) 019] through transcription factors to coregulate gene transcription (8,9). Furthermore, genomic analysis suggests that the "phyA-promoter association" model is a universal mechanism of regulation for thousands of phyA-associated genes (9).…”

mentioning

confidence: 99%

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Photoreceptor partner FHY1 has an independent role in gene modulation and plant development under far-red light

Chen

Demone

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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To incorporate the far-red light (FR) signal into a strategy for optimizing plant growth, FAR-RED ELONGATED HYPOCOTYL1 (FHY1) mediates the nuclear translocation of the FR photoreceptor phytochrome A (phyA) and facilitates the association of phyA with the promoters of numerous associated genes crucial for the response to environmental stimuli. However, whether FHY1 plays additional roles after FR irradiation remains elusive. Here, through the global identification of FHY1 chromatin association sites through ChIP-seq analysis and by the comparison of FHY1-associated sites with phyA-associated sites, we demonstrated that nuclear FHY1 can either act independently of phyA or act in association with phyA to activate the expression of distinct target genes. We also determined that phyA can act independently of FHY1 in regulating phyA-specific target genes. Furthermore, we determined that the independent FHY1 nuclear pathway is involved in crucial aspects of plant development, as in the case of inhibited seed germination under FR during salt stress. Notably, the differential presence of cis-elements and transcription factors in common and unique FHY1-and/or phyA-associated genes are indicative of the complexity of the independent and coordinated FHY1 and phyA pathways. Our study uncovers previously unidentified aspects of FHY1 function beyond its currently recognized role in phyA-dependent photomorphogenesis.L ight is one of the most important environmental cues in plant growth and development. Arabidopsis has thus evolved several photoreceptors to perceive different wavelengths in the visible light spectrum (1). Among them, phytochrome A (phyA) is the primary photoreceptor to mediate the far-red light (FR) and early red light (R) responses (2, 3). PhyA therefore plays a predominant role in plant adaptation to a shade environment where the R/FR ratio decreases. Upon FR and R irradiation phyA will shuttle between the inactive R-absorbing Pr form and the active FR-absorbing Pfr form. These two forms display distinct biological activities, nuclear translocation rates, degradation rates, and affinities for various signaling intermediates (2, 4, 5).Both FR and R trigger the localization of cytosolic phyA to the nucleus (6), albeit through different mechanisms. Two essential partners for phyA nuclear translocation, FAR-RED ELONGATED HYPOCOTYL1 (FHY1) and its less abundant homolog FHY1-LIKE (FHL), influence this process at two levels; first, after the initial burst of phyA nuclear importation under R, FHY1 is gradually phosphorylated by action of the Pfr form of phyA (7). This event inhibits the nuclear translocation of FHY1 and consequently prevents further nuclear accumulation of phyA. Under FR, however, persistent phyA nuclear translocation is observed with nonphosphorylated FHY1 (8); second, the nucleo-cytoplasmic shuttling of FHY1/FHL is also reduced under R owing to the low dissociation rate of the Pfr-FHY1/ FHL complex. The FR-driven phyA conversion to its Pr form benefits the recycling of FHY1/FHL for continuous phyA n...

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“…S2A). This result is consistent with the observation that FHY1 accumulates in the nucleus upon FR irradiation (8).…”

Section: Fhy1 and Phya Coordinately Regulate Their Common Direct Targetsupporting

confidence: 82%

“…S1B). Their positions were consistent with that of G-boxes, DNA elements that are critical for phyA-dependent CHS and NAC019 expression (8,9).…”

Section: Resultssupporting

confidence: 52%