CAREER: Defining the evolutionary trajectory of CAM photosynthesis in Portulacineae (Caryophyllales)

天冬酸代谢（CAM）是指光合作用途径的一系列变化，这些变化使植物在干旱、高温和/或低大气二氧化碳的条件下更有效地生长。它在生物化学上类似于另一种修饰，C4光合作用，但对叶组织的结构改变较少。我们对C4综合征的进化史了解甚多，这些知识已经为通过基因工程将这种光合作用改进应用于水稻等作物的努力提供了信息。我们对CAM的进化几乎一无所知——它的遗传基础，它与其他植物性状的关系，以及它是否同样可能在所有植物谱系中进化。在这里，PI建议显著增加我们对CAM如何进化的理解，利用比较方法并专注于一种具有耐旱性的重要园艺植物谱系，其中包括仙人掌。该项目包括广泛的遗传和生态分析，并将开发一种新的指标来有效筛选低水平CAM活性的物种。由于这是一个职业奖，该项目的所有研究目标都紧密地交织在一个创新的教育计划中，涉及布朗大学的本科生、研究生、博士后研究人员和来自秘鲁的研究生。除了将获得的基本科学认识外，该项目还将为CAM光合作用在工程上更抗旱作物的应用提供有价值的见解。此外，它将在美国和秘鲁之间建立科学合作的基础桥梁，并为发展中国家的能力建设和科学培训作出重大贡献。

Crassulacean Acid Metabolism (CAM) refers to a set of changes to the photosynthetic pathway that allows plants to grow more efficiently under conditions of drought, high temperatures, and/or low atmospheric CO2. It is biochemically similar to another modification, C4 photosynthesis, but requires fewer structural changes to leaf tissue. We know a great deal about the evolutionary history of the C4 syndrome, and this knowledge has informed efforts to genetically engineer this photosynthetic improvement into crops such as rice. We know virtually nothing about CAM evolution- its genetic underpinnings, its relationship to other plant traits, and whether it is equally likely to evolve in all plant lineages. Here the PI proposes to significantly increase our understanding of how CAM evolves, utilizing a comparative approach and focusing on one horticulturally important plant lineage known for drought tolerance, which includes the cacti. The project involves extensive genetic and ecological analyses, and will also develop a new metric to efficiently screen species for low level CAM activity. Because this is a CAREER award, all research goals of the project are tightly interwoven into an innovative education program involving undergraduates, graduate students, and post-doctoral researchers at Brown University, and graduate students from Peru. In addition to the basic scientific understanding that will be gained, this project should yield valuable insight into the use of CAM photosynthesis for engineering more drought-resistant crops. Moreover it will build a foundational bridge of scientific collaboration between the United States and Peru, and contribute significantly to capacity building and scientific training in a developing nation.