Smet Dajo, Žádníková Petra, Vandenbussche Filip, Benková Eva, Van Der Straeten Dominique
Laboratory of Functional Plant Biology, Department of Physiology, Ghent University, 9000, Gent, Belgium.
Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), 9052, Gent, Belgium.
New Phytol. 2014 Jun;202(4):1398-1411. doi: 10.1111/nph.12751. Epub 2014 Mar 10.
Germination of Arabidopsis seeds in darkness induces apical hook development, based on a tightly regulated differential growth coordinated by a multiple hormone cross-talk. Here, we endeavoured to clarify the function of brassinosteroids (BRs) and cross-talk with ethylene in hook development. An automated infrared imaging system was developed to study the kinetics of hook development in etiolated Arabidopsis seedlings. To ascertain the photomorphogenic control of hook opening, the system was equipped with an automatic light dimmer. We demonstrate that ethylene and BRs are indispensable for hook formation and maintenance. Ethylene regulation of hook formation functions partly through BRs, with BR feedback inhibition of ethylene action. Conversely, BR-mediated extension of hook maintenance functions partly through ethylene. Furthermore, we revealed that a short light pulse is sufficient to induce rapid hook opening. Our dynamic infrared imaging system allows high-resolution, kinetic imaging of up to 112 seedlings in a single experimental run. At this high throughput, it is ideally suited to rapidly gain insight in pathway networks. We demonstrate that BRs and ethylene cooperatively regulate apical hook development in a phase-dependent manner. Furthermore, we show that light is a predominant regulator of hook opening, inhibiting ethylene- and BR-mediated postponement of hook opening.
拟南芥种子在黑暗中萌发会诱导顶端弯钩发育，这一过程基于多种激素相互作用协调的严格调控的差异生长。在此，我们致力于阐明油菜素内酯（BRs）的功能以及其在弯钩发育中与乙烯的相互作用。我们开发了一种自动红外成像系统来研究黄化拟南芥幼苗弯钩发育的动力学。为了确定弯钩张开的光形态建成控制，该系统配备了自动调光器。我们证明乙烯和BRs对于弯钩的形成和维持是不可或缺的。乙烯对弯钩形成的调控部分通过BRs起作用，同时BRs对乙烯作用具有反馈抑制。相反，BR介导的弯钩维持延长部分通过乙烯起作用。此外，我们发现短光脉冲足以诱导弯钩快速张开。我们的动态红外成像系统能够在单次实验中对多达112株幼苗进行高分辨率的动力学成像。在这种高通量下，它非常适合快速洞察信号通路网络。我们证明BRs和乙烯以阶段依赖的方式协同调控顶端弯钩发育。此外，我们表明光是弯钩张开的主要调节因子，抑制乙烯和BR介导的弯钩张开延迟。
