Dissertation Research: Assembly, maintenance, and function of the plant-endophyte symbiosis

生活在我们星球上的每一种植物的叶子里都有不同的微观真菌群落，称为真菌内生菌。与引起植物疾病的病原体不同，真菌内生菌对其植物宿主是有益的。由于内生菌对植物的多种健康益处，目前在可持续农业和生物防治中使用内生菌具有极大的兴趣。虽然最近的研究已经开始表征内生菌群落及其在农作物和其他植物中的功能，但我们缺乏内生菌如何使它们所生活的植物受益的基本知识。正如我们了解药物促进人类健康的机制一样，了解内生菌与植物生理学和免疫系统相互作用的机制对于在恢复生态学和可持续农业中使用这些真菌至关重要。这项研究将致力于揭示这些机制，提高对植物和真菌内生菌如何以及为什么形成和维持其有益关系的认识。此外，本研究将培训本科生，以及高中生。本研究将使用可可树可可作为宿主物种，研究植物-内生菌相互作用的组装，维护和功能。首先，研究人员将使用总RNA测序来了解植物和真菌基因表达的变化是如何在将落叶应用于同种幼苗后增加植物病原体抗性的。研究人员预计，暴露于落叶（内生菌接种物的来源）不仅会改变植物的基线基因表达，还会改变植物对病原体感染的遗传反应。第二，该项目将使用稳定同位素技术来跟踪植物和内生菌之间的营养交换，并确定植物是否“支付”内生菌来对抗它们的敌人。研究人员假设，植物可以将营养物质导向更有益的内生真菌。

Living within the leaves of every plant species on our planet are diverse communities of microscopic fungi, known as fungal endophytes. Unlike pathogens that cause plant disease, fungal endophytes can be beneficial for their plant hosts. Due to their variety of health benefits for plants, there is currently great interest in using endophytes in sustainable agriculture and biological control. Although recent research has begun characterizing endophyte communities and their functions in agricultural crops and other plants, we lack basic knowledge of how endophytes benefit the plants in which they live. Just as we understand the mechanisms by which drugs promote human health, understanding the mechanisms by which endophytes interact with plant physiology and the immune system is imperative for using these fungi in restoration ecology and sustainable agriculture. This research will work to uncover these mechanisms, improving knowledge of how and why plants and fungal endophytes form and maintain their beneficial relationships. Additionally, this research will train undergraduate students, as well as high school students.This research will use Theobroma cacao, the cacao tree, as a host species for studying assembly, maintenance, and function of the plant-endophyte interaction. First, the researchers will use total RNA sequencing to understand how changes in plant and fungal gene expression underlie increased plant pathogen resistance following application of leaf litter to conspecific seedlings. The researchers expect that exposure to leaf litter, a source of endophytic inoculum, will not only alter baseline gene expression in plants, but will also change how plants respond genetically to pathogen infection. Second, this project will use stable-isotope techniques to track the nutrient exchange between plants and endophytes, and determine if plants "pay" endophytes to mount an immune response against their enemies. The researchers hypothesize that plants can direct nutrients toward more beneficial endophytic fungi.