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Plant Communications：拟南芥隐花色素CRY1影响分枝，从而改变植株的株型结构

已有 3019 次阅读 2020-4-9 09:57 |个人分类:每日摘要|系统分类:论文交流

Cryptochrome 1 Inhibits Shoot Branching by Repressing the Self-activated Transcription Loop of PIF4 in Arabidopsis

First author: Huawei Zhai; Affiliations: CAAS Institute of Crop Science (中国农科院作物科学研究所): Beijing, China

Corresponding author: Bin Liu

Cryptochrome 1 (CRY1) is an important light receptor essential for de-etiolation of Arabidopsis seedlings. However, its functions in regulating plant architecture are still unclear. Here we show that mutation in CRY1 resulted in an increased branching phenotype. To investigate the underlying mechanism, we analyzed the expression profiles of branching related genes and found that the mRNA levels of Phytochrome Interaction Factor 4 (PIF4) and PIF5 are significantly increased in the cry1 mutant. Genetic analysis showed that the pif4 or pif4 pif5 mutant is epistatic to the cry1 mutant and overexpression of PIF4 conferred increased branching. Moreover, we demonstrate that the PIF4 protein physically associates with the G-box motif within the PIF4 promoter to form a self-activated transcriptional feedback loop, while CRY1 represses this process in response to blue light. Taken together, this study suggests a CRY1-PIF4 module to regulate gene expression and branching in response to ambient light conditions.

隐花色素CRY1是一个重要的光受体，对于拟南芥幼苗的去黄化（de-etiolation）是必需的。然而，其在植物结构调控方面的功能还不清楚。本文中，作者发现CRY1基因的功能缺失突变会导致分枝增多的表型。为了研究潜在的分子机制，作者分析了分枝相关基因的表达谱，结果发现cry1突变体植株中光敏色素互作因子PIF4和PIF5的mRNA水平显著升高。遗传分析显示pif4单突或者pif4 pif5双突对于cry1突变是上位的，并且PIF4基因的过表达能够获得分枝增多的表型。此外，作者发现PIF4蛋白与其自身编码基因启动子区的G-box基序能够物理互作，从而形成了自激活的转录反馈回路，而CRY1蛋白则能响应于蓝光而抑制该进程。综上，本文的研究揭示了一个CRY1-PIF4模块，该模块能够响应于周边的光照条件，从而调控基因的表达，影响植株分枝，最终改变植株的株型结构。