RUI: Geographic Variation in Activated Antiherbivore Defenses

本研究的目的是评估藻类中激活的抗食草动物化学防御系统的有效性，并确定这些防御的地理趋势。在这个防御系统中，当植物受到食草动物的伤害时，藻类产生的二甲基磺酰丙酸酯（DMSP）通过DMSP裂解酶转化为二甲基硫醚（DMS）和丙烯酸。DMS和丙烯酸都是有效的饲养阻止剂。由于一般认为低纬度地区的放牧压力比高纬度地区高，因此PI将测量四个地区藻类DMSP和DMSP裂解酶的产量：温带东北太平洋地区、温带南太平洋地区、热带太平洋地区和热带大西洋地区。在每个地区，研究人员将评估DMSP激活防御系统对当地食草动物的有效性，以及温度、营养物质和紫外线等环境因素变化对DMSP和DMSP裂解酶产生的影响。这项研究的结果将提供关于化学防御和植物-食草动物相互作用如何在世界不同地区进化的信息，它们如何随空间和时间变化，以及它们如何受到环境变化的影响。本研究每年将为数名本科生和硕士生提供培训机会。十几名学生将参与这项工作的各个方面，并将在最先进的分析方法、实验设计概念、统计分析以及使用计算机程序分析数据和向其他科学家展示他们的工作结果方面接受宝贵的培训。

The goals of this research are to assess the effectiveness of an activated anti-herbivore chemical defense system in algae, and to identify geographic trends in these defenses. In this defense system, dimethylsulfonioproprionate (DMSP) produced by the algae is converted with the enzyme DMSP lyase, to dimethyl sulfide (DMS) and acrylic acid when the plant is damaged by herbivores. Both DMS and acrylic acid can be potent feeding deterrents. Because grazing pressures are generally thought to be higher at lower latitudes than at higher latitudes, the PI will measure the production of DMSP and DMSP lyase from algae in four regions: the temperate northeastern Pacific region, the temperate Southern Pacific region, the tropical Pacific region, and the tropical Atlantic region. In each region, the investigators will assess the effectiveness of the DMSP activated defense system on local herbivores and the effects of changes in environmental factors such as temperature, nutrients, and ultraviolet light, on the production of DMSP and DMSP lyase. The results of this study will provide information on how chemical defenses and plant-herbivore interactions have evolved in different parts of the world, how they vary over space and time, and how they are affected by changes in the environment. This research will provide training opportunities for several undergraduate and master's level students during each year of the project. Over a dozen students will be involved in all aspects of the work and will receive valuable training in state-of-the-art analytical methods, experimental design concepts, statistical analyses, and the use of computer programs for analyzing data and presenting the results of their work to other scientists.