Dynamic Antagonism between Phytochromes and PIF Family Basic Helix-Loop-Helix Factors Induces Selective Reciprocal Responses to Light and Shade in a Rapidly Responsive Transcriptional Network in Arabidopsis
Dynamic Antagonism between Phytochromes and PIF Family Basic Helix-Loop-Helix Factors Induces Selective Reciprocal Responses to Light and Shade in a Rapidly Responsive Transcriptional Network in Arabidopsis
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DOI：
10.1105/tpc.112.095711
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发表时间：
2012-04-01
期刊：
影响因子：
11.6
通讯作者：
Quail, Peter H.
中科院分区：
文献类型：
--
作者：
Leivar, Pablo;Tepperman, James M.;Quail, Peter H.
植物通过光敏色素（phytochrome, phy）诱导的适应性变化来响应阴影调制的光信号，称为避光。为了研究光敏色素相互作用的基本螺旋-环-螺旋因子PIF1、3、4和5在将这些信号传递到转录网络中的作用，我们比较了野生型和四重pif （pifq）突变体的阴影响应转录组谱。我们确定了一个基因子集，富含转录因子编码位点，以pif依赖的方式快速响应阴影，并包含启动子G-box基序，已知与pif结合。这些基因是调节初级下游转录回路的phy-PIF信号传导的潜在直接靶点。第二种pif依赖的早期反应基因，缺乏G-box基序，在生长素反应位点中富集，因此是物理pif信号传导的潜在间接靶点，介导阴影诱导的快速细胞扩增。比较去条带化和阴影响应转录组确定了另一个包含g -box的基因子集，这些基因对光照和阴影信号相互表现出快速抑制和诱导。这些数据定义了一组核心的转录和激素过程，这些过程似乎动态地准备通过物理和pif相互拮抗作用的扰动对光环境变化做出快速反应。比较pifq和三重pif突变体对光照和阴影的响应，证实了pif在幼苗形态发生和转录调控中具有重叠冗余，但每个pif对这些响应的贡献不同。
Plants respond to shade-modulated light signals via phytochrome (phy)-induced adaptive changes, termed shade avoidance. To examine the roles of Phytochrome-Interacting basic helix-loop-helix Factors, PIF1, 3, 4, and 5, in relaying such signals to the transcriptional network, we compared the shade-responsive transcriptome profiles of wild-type and quadruple pif (pifq) mutants. We identify a subset of genes, enriched in transcription factor-encoding loci, that respond rapidly to shade, in a PIF-dependent manner, and contain promoter G-box motifs, known to bind PIFs. These genes are potential direct targets of phy-PIF signaling that regulate the primary downstream transcriptional circuitry. A second subset of PIF-dependent, early response genes, lacking G-box motifs, are enriched for auxin-responsive loci, and are thus potentially indirect targets of phy-PIF signaling, mediating the rapid cell expansion induced by shade. Comparing deetiolation- and shade-responsive transcriptomes identifies another subset of G-box-containing genes that reciprocally display rapid repression and induction in response to light and shade signals. These data define a core set of transcriptional and hormonal processes that appear to be dynamically poised to react rapidly to light-environment changes via perturbations in the mutually antagonistic actions of the phys and PIFs. Comparing the responsiveness of the pifq and triple pif mutants to light and shade confirms that the PIFs act with overlapping redundancy on seedling morphogenesis and transcriptional regulation but that each PIF contributes differentially to these responses.