Molecular genetics of hormone signaling

我的主要研究兴趣是激素如何调节高等植物的发育反应。通过NSERC发现补助金的资助，我把实验室的工作重点放在了一些激素的作用上，包括乙烯、赤霉素（GA），特别是脱落酸（阿坝）。然而，最近随着化学遗传学的出现，我们现在相信可以获得关于小有机分子如何调节植物生长和发育的新见解，这是使用传统分子遗传学方法不可能实现的。为此，我们建立了一个化学遗传学程序，解剖拟南芥种子发芽。使用基因型特异性筛选，我们已经确定了一组与一组称为独脚金内酯的化合物具有相似性质的化学物质。独脚金内酯首先被鉴定为寄生杂草种子萌发刺激剂。寄生杂草被认为是发展中国家最具破坏性的农业媒介。仅在非洲，独脚金物种就已经侵扰了多达三分之二的可耕地，并造成作物产量的巨大损失。寄生植物的种子是高度休眠的，只有当它们感觉到宿主根释放的独脚金内酯时才会发芽。在此之后，发芽幼苗的根穿透宿主并与宿主发生寄生相互作用。使用我们的模型系统，我们已经能够显示有一个密切的关系独脚金内酯行动，阿坝/GA信号和光信号在拟南芥。我们将结合使用化学、遗传学和分子方法来进一步了解这些关系。使用化学遗传学与拟南芥遗传学相结合的方法鉴定独脚金内酯证明了这种新技术鉴定参与植物生长的新分子的能力。在NSERC发现赠款计划的资助下，我们将首次有机会了解独脚金内酯在宿主-寄生虫相互作用中的分子基础。

My main research interests are concerned with how hormones regulate developmental responses in higher plants. Through NSERC Discovery Grant funding I have focused the efforts of my laboratory on the roles of a number of hormones including ethylene, gibberellins (GA) and in particular abscisic acid (ABA). However, recently with the advent of chemical genetics we now believe new insights can be gained on how small organic molecules regulate plant growth and development that were not possible using traditional molecular genetics approaches. To this end, we have established a chemical genetics program to dissect germination in Arabidopsis seeds. Using genotypic specific screens, we have identified a collection of chemicals that have similar properties to a group of compounds called strigolactones. Strigolactones were first identified as seed germination stimulants of parasitic weeds. Parasitic weeds are considered the most damaging agricultural agents in the developing world. In Africa alone, Striga species have infested up to two-thirds of the arable land and cause huge losses in crop yields. Parasitic plant seeds are highly dormant and only germinate when they sense strigolactones that are released by the host root. After this point, the root of the germinating seedling penetrates the host and develops a parasitic interaction with the host. Using our model system we have been able to show there is a close relationship between strigolactone action, ABA/GA signaling and light signaling in Arabidopsis. We will use a combination of chemical, genetics and molecular approaches to further understand these relationships. The identification of strigolactones using a a combined approach of chemical genetics with Arabidopsis genetics demonstrates the power of this new technology to identifying new molecules involved in plant growth. With funding from the NSERC Discovery Grants program we will have an opportunity for the first time to understand the molecular underpinnings of strigolactones in host-parasite interactions.