Light serves as a crucial environmental cue which modulates plant growth and development, and which is controlled by multiple photoreceptors including the primary red light photoreceptor,phytochrome B(phyB). The signa...Light serves as a crucial environmental cue which modulates plant growth and development, and which is controlled by multiple photoreceptors including the primary red light photoreceptor,phytochrome B(phyB). The signaling mechanism of phyB involves direct interactions with a group of basic helix-loop-helix(bHLH) transcription factors, PHYTOCHROME-INTERACTING FACTORS(PIFs), and the negative regulators of photomorphogenesis, COP1 and SPAs. H2 A.Z is an evolutionarily conserved H2 A variant which plays essential roles in transcriptional regulation. The replacement of H2 A with H2 A.Z is catalyzed by the SWR1 complex. Here, we show that the Pfr form of phyB physically interacts with the SWR1 complex subunits SWC6 and ARP6. phyB and ARP6 coregulate numerous genes in the same direction,some of which are associated with auxin biosynthesis and response including YUC9, which encodes a rate-limiting enzyme in the tryptophandependent auxin biosynthesis pathway. Moreover,phyB and HY5/HYH act to inhibit hypocotyl elongation partially through repression of auxin biosynthesis. Based on our findings and previous studies, we propose that phyB promotes H2 A.Z deposition at YUC9 to inhibit its expression through direct phyB-SWC6/ARP6 interactions,leading to repression of auxin biosynthesis, and thus inhibition of hypocotyl elongation in red light.展开更多
Light is an essential environmental signal perceived by a broad range of photoreceptors in plants. Among them, the red/far-red light receptor phytochromes function to promote photomorphogenesis, which is critical to t...Light is an essential environmental signal perceived by a broad range of photoreceptors in plants. Among them, the red/far-red light receptor phytochromes function to promote photomorphogenesis, which is critical to the survival of seedlings after seeds germination. The basic-helix-loop-helix transcription factors phytochrome-interacting factors (PIFs) are the pivotal direct downstream components of phytochromes. H2A.Z is a highly conserved histone variant regulating gene transcription, and its incorporation into nucleosomes is catalyzed by SWI2/SNF2-related 1 complex, in which SWI2/SNF2-related 1 complex subunit 6 (SWC6) and actin-related protein 6 (ARP6) serve as core subunits. Here, we show that PIFs physically interact with SWC6 in vitro and in vivo, leading to the disassociation of HY5 from SWC6. SWC6 and ARP6 regulate hypocotyl elongation partly through PIFs in red light. PIFs and SWC6 coregulate the expression of auxin-responsive genes such as IAA6, IAA19, IAA20, and IAA29 and repress H2A.Z deposition at IAA6 and IAA19 in red light. Based on previous studies and our findings, we propose that PIFs inhibit photomorphogenesis, at least in part, through repression of H2A.Z deposition at auxin-responsive genes mediated by the interactions of PIFs with SWC6 and promotion of their expression in red light.展开更多
基金supported by The National Natural Science Foundation of China grants to Z.M.(31900609)The National Key Research and Development Program of China grant(2017YFA0503802)+1 种基金The National Natural Science Foundation of China grants to H.Q.Y.(31530085),W.W.(31900207)and T.G.(32000183)The Science and Technology Commission of Shanghai Municipality grant(18DZ2260500)。
文摘Light serves as a crucial environmental cue which modulates plant growth and development, and which is controlled by multiple photoreceptors including the primary red light photoreceptor,phytochrome B(phyB). The signaling mechanism of phyB involves direct interactions with a group of basic helix-loop-helix(bHLH) transcription factors, PHYTOCHROME-INTERACTING FACTORS(PIFs), and the negative regulators of photomorphogenesis, COP1 and SPAs. H2 A.Z is an evolutionarily conserved H2 A variant which plays essential roles in transcriptional regulation. The replacement of H2 A with H2 A.Z is catalyzed by the SWR1 complex. Here, we show that the Pfr form of phyB physically interacts with the SWR1 complex subunits SWC6 and ARP6. phyB and ARP6 coregulate numerous genes in the same direction,some of which are associated with auxin biosynthesis and response including YUC9, which encodes a rate-limiting enzyme in the tryptophandependent auxin biosynthesis pathway. Moreover,phyB and HY5/HYH act to inhibit hypocotyl elongation partially through repression of auxin biosynthesis. Based on our findings and previous studies, we propose that phyB promotes H2 A.Z deposition at YUC9 to inhibit its expression through direct phyB-SWC6/ARP6 interactions,leading to repression of auxin biosynthesis, and thus inhibition of hypocotyl elongation in red light.
基金This work was supported by the National Natural Science Foundation of China(31900609)the National Key Research and Development Program of China(2017YFA0503802)+1 种基金the National Natural Science Foundation of China(31530085,31900207,and 32000183)the Science and Technology Commission of Shanghai Municipality(18DZ2260500).
文摘Light is an essential environmental signal perceived by a broad range of photoreceptors in plants. Among them, the red/far-red light receptor phytochromes function to promote photomorphogenesis, which is critical to the survival of seedlings after seeds germination. The basic-helix-loop-helix transcription factors phytochrome-interacting factors (PIFs) are the pivotal direct downstream components of phytochromes. H2A.Z is a highly conserved histone variant regulating gene transcription, and its incorporation into nucleosomes is catalyzed by SWI2/SNF2-related 1 complex, in which SWI2/SNF2-related 1 complex subunit 6 (SWC6) and actin-related protein 6 (ARP6) serve as core subunits. Here, we show that PIFs physically interact with SWC6 in vitro and in vivo, leading to the disassociation of HY5 from SWC6. SWC6 and ARP6 regulate hypocotyl elongation partly through PIFs in red light. PIFs and SWC6 coregulate the expression of auxin-responsive genes such as IAA6, IAA19, IAA20, and IAA29 and repress H2A.Z deposition at IAA6 and IAA19 in red light. Based on previous studies and our findings, we propose that PIFs inhibit photomorphogenesis, at least in part, through repression of H2A.Z deposition at auxin-responsive genes mediated by the interactions of PIFs with SWC6 and promotion of their expression in red light.
