Fig. 8: PIF7 physically interacts with REF6 to contribute to shade avoidance memory. | Nature Communications

Fig. 8: PIF7 physically interacts with REF6 to contribute to shade avoidance memory.

From: PHYTOCHROME-INTERACTING FACTOR 7 and RELATIVE OF EARLY FLOWERING 6 act in shade avoidance memory in Arabidopsis

Fig. 8

a Interaction between PIF7 and the REF6C-terminal as detected by a luciferase complementation imaging (LCI) assay in Nicotiana benthamiana. b Interaction between PIF7 and the REF6C-terminal as detected by an in vitro GST pull-down assay. TF-His-fused PIF7 and GST-REF6C-terminal were purified from E. coli. c Interaction between PIF7 and REF6 in Arabidopsis as detected by an in vivo Co-IP assay. Anti-HA beads were used to precipitate REF6-HA from proREF6::REF6-HA/ref6-1*35S::PIF7-Flash seedlings grown under N_WL and N_SH 1 h. PIF7 and REF6 were detected by anti-Flag and anti-HA antibodies. d Shade effects on the interactions between PIF7 and REF6 in Arabidopsis was examined by Co-IP assays. Anti-Flag beads were used to precipitate PIF7-Flash from proREF6::REF6-HA/ref6-1*35S::PIF7-Flash seedlings grown under N_WL, N_SH 1 h and N_SH 8 h. PIF7 and REF6 were detected by anti-Flag and anti-HA antibodies. e Hypocotyl lengths of Col-0, pif7-1, ref6-1, ref6-3, pif7-1ref6-1 and pif7-1ref6-3 grown under P conditions which are shown in supplementary Fig. 1d. f Shade-triggered growth rates and average growth rates of Col-0, pif7-1ref6-1 and pif7-1ref6-3 seedlings under N and P conditions. g Proposed working model of the PIF7 and REF6 during shade-avoidance memory. Under white light, the chromatin of certain shade-memory-related genes carry repressive histone modifications (H3K27me3) that inhibit spontaneous transcription. After 8 h priming shade, the accumulated PIF7 recruits REF6 to demethylate H3K27me3 and activates these certain shade-memory-related genes (e.g., PRE1, YUCCA2, IAA19, GH3.6 and BGL1). During recovering white light condition, the expression levels of these certain shade-memory-related genes returned to normal levels in white light, but low levels of H3K27me3 were primed on these genes. When shade reoccurs, PIF7 quickly activates their expressions. In e and f, data are presented as mean values +/− SD (e) and SE (f) and the P value was calculated by One-way ANOVA with Tukey’s HSD test (e) and Student’s two-sided t-test (f), respectively, and significant differences are shown by ****(P < 0.0001). Source data are provided as a Source Data file.

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