![]()
In vivo gibberellin gradients visualized in rapidly elongating tissues
First author:Annalisa Rizza; Affiliations: Cambridge University (剑桥大学): Cambridge, UK
Corresponding author: Alexander M. Jones
The phytohormone (植物激素) gibberellin (GA) is a key regulator of plant growth and development. Although the upstream regulation and downstream responses to GA vary across cells and tissues, developmental stages and environmental conditions, the spatiotemporal distribution (时空分布) of GA in vivo remains unclear. Using a combinatorial screen in yeast, we engineered an optogenetic biosensor (光遗传生物传感器), GIBBERELLIN PERCEPTION SENSOR 1 (GPS1; 赤霉素感知传感器), that senses nanomolar (纳摩尔) levels of bioactive GAs. Arabidopsis thaliana plants expressing a nuclear localized GPS1 report on GAs at the cellular level. GA gradients were correlated with gradients of cell length in rapidly elongating roots and dark-grown hypocotyls (下胚轴). In roots, accumulation of exogenously applied (外加的) GA also correlated with cell length, intimating (示意) that a root GA gradient can be established independently of GA biosynthesis. In hypocotyls, GA levels were reduced in a phytochrome interacting factor (pif) quadruple mutant (四突变体) in the dark and increased in a phytochrome double mutant in the light, indicating that PIFs elevate (提高) GA in the dark and that phytochrome inhibition of PIFs could lower GA in the light. As GA signalling directs hypocotyl elongation largely through promoting PIF activity, PIF promotion of GA accumulation represents a positive feedback loop within the molecular framework driving rapid hypocotyl growth.
植物激素赤霉素GA是植物生长发育重要的调控因子。尽管其上游调控及下游响应在不同细胞组织、发育阶段及环境条件下变异很大，然而其在植物体内的时空分布情况还不清楚。本文利用对酵母的筛选，构建了一个赤霉素感知传感器GPS1，其可以感知细胞中纳摩尔水平的具生物活性GAs。拟南芥植物的细胞水平表达一个核定位的GA报告蛋白GPS1。GA的梯度与快速生长的根及黑暗条件下生长的下胚轴中的细胞长度梯度相关。在根中，外施GA的积累也与细胞长度相关，这暗示着根中GA梯度可能独立于GA的生物合成。在下胚轴中，黑暗下pif四突变体的GA水平降低，而光照下光敏色素双突变体的GA水平升高，表明PIFs提高黑暗条件下GA的水平，而PIFs的光敏色素抑制会降低GA的水平。GA信号通过促进PIF活性来直接调控下胚轴的伸长，而PIF促进GA的积累意味着一个正向反馈调控以促进下胚轴的快速生长。
通讯：Alexander M. Jones
个人简介：加利福尼亚大学戴维斯分校，植物生物学，学士；加利福尼亚大学戴伯克利分校，植物与微生物的相互作用，博士；卡内基科学中心，植物激素模式与动态，博士后。
研究方向：植物激素的荧光共振能量转移（FRET）生物感应器研究。
doi: 10.1038/s41477-017-0021-9
Journal: Nature Plants
Published online: October 2, 2017.
Nature Plants：植物体内快速伸长组织的GA梯度可视化 |
收藏
分享
支持
反对
提升卡
置顶卡
沉默卡
喧嚣卡
变色卡
千斤顶
照妖镜
