Dissertation Research: Phylogeny and Functional Evolution of High Affinity Nitrate Transporters in Fungi

硝酸盐转运体向与树根共生的蘑菇形成真菌（以及其他生物）输送营养氮，但硝酸盐转运体基因如何进化及其对森林生态的相对意义尚不清楚。本项目研究了硝酸盐转运体如何在蘑菇适应其生态位的过程中进化和功能多样化。该项目的两个具体目标是：(1)利用DNA和氨基酸序列分析来建立真菌中硝酸盐转运基因的进化假设，提高我们对某些类群真菌分类的认识；(2)分析不同氮生态位蘑菇在一系列环境条件下对硝酸盐转运基因的利用模式。该项目解决了环境氮在蘑菇形成真菌的生物多样性和进化中的重要性，并特别关注与树木形成共生关系的一组真菌。氮污染是一个广泛的生态问题，特别是与这些森林真菌的多样性丧失有关。这种损失威胁到直接依赖它们的森林生态系统的复原力和生存能力。该项目将为开发利用蘑菇形成真菌对抗氮污染影响的生物修复策略提供分子框架。

Nitrate transporters deliver nutritional nitrogen to (among other organisms) mushroom forming fungi living in symbiosis with tree roots, yet how nitrate transporter genes evolve and their relative significance to forest ecology is not well understood. This project investigates how nitrate transporters have evolved and diversified in function during a mushroom's adaptation to its ecological niche. Two specific goals of the project are (1) to use DNA and amino acid sequence analysis to develop an hypothesis of the evolution of nitrate transporter genes in the fungi and improve our understanding of fungal taxonomy in some groups and (2) to analyze the patterns of nitrate transporter gene utilization by mushrooms from divergent nitrogen niches under an array of environmental conditions. This project addresses the importance of environmental nitrogen in the biodiversity and evolution of mushroom forming fungi with a specific focus on a group that forms symbiotic associations with trees. Nitrogen pollution is a broad ecological concern specifically implicated in the recent loss of diversity of these forest fungi. Such a loss threatens the resiliency and viability of the forest ecosystems that depend upon them directly. This project will provide a molecular framework for developing strategies of bioremediation using mushroom forming fungi to counter the impacts of nitrogen pollution.