A Microbial Observatory in the Duke Forest: Exploring Fungal Diversity in Response to Environmental Change

在许多大型生态学研究中，真菌的多样性及其在生态系统功能和变化中的作用几乎完全被忽视。DNA测序、生物信息学和系统发育分析等领域的最新进展使微生物多样性研究取得许多进展成为可能。目前正在开发一种基于分子系统学的杜克森林真菌生物多样性常规调查系统。杜克森林位于北卡罗莱纳州山前高原的东部边缘，支持多种植物物种（超过100种树种）、土壤和土地利用条件，目前正在进行的研究项目包括节肢动物多样性调查、环境变化影响的研究（包括二氧化碳升高）、不同的土地利用历史，以及自然演变的森林群落的动态。杜克森林真菌学观测站（DFMO）将允许对温带森林中形成腐生菌和菌根真菌核心群的真菌群落进行研究。作为一个试点项目，将对代表一系列森林类型的地块进行调查，以便建立森林担子菌多样性的基线数据集。接下来将研究几个长期研究中的地块，包括最近启动的自由空气二氧化碳富集（FACE）实验。FACE研究的早期数据表明土壤中微生物种群的变化，但迄今为止还没有FACE对微生物多样性的调查。菌根真菌的丰度、活性和多样性尤其可能发生变化（作为对FACE样地根系分泌物供应增加的反应），并可能在森林/生态系统的长期健康和稳定中发挥重要作用。本研究将开发一个dna序列数据库框架（基于核糖体ITS序列），与杜克森林内的位点相关联。对于大多数真菌类群，已经有了广泛的分子数据库，这使得在大多数情况下可以将分离物鉴定为属，并且通常可以鉴定为种。重点将放在这些地点的土壤、凋落物和菌根样本上，这将比基于“地上”果实体采样或可栽培多样性的估计提供更公正的微生物多样性估计。这些数据将成为长期监测杜克森林和FACE站点真菌微生物多样性的基础。该项目将提供来自不同生境的土壤、菌根、土壤和凋落物真菌的基线数据。该项目也将是首次研究真菌群落结构，以评估各种环境变量（如二氧化碳浓度增加）对真菌多样性的影响。

In many large-scale ecological studies the diversity of fungi and their roles in ecosystem function and change are almost totally ignored. Recent advances in the fields of DNA sequencing, bioinformatics, and phylogenetic analysis have made possible many advances in studies of microbial diversity. A system for performing routine surveys of fungal biodiversity in Duke Forest (Durham, NC) based on molecular systematics is being developed. The Duke Forest lies near the eastern edge of the North Carolina piedmont plateau and supports diverse plant species (over100 tree species), soils, and land use conditions and research projects currently underway include surveys of arthropod diversity, studies of the effects of environmental change including elevated carbon dioxide, different land use histories, and the dynamics of naturally evolving forest communities. The Duke Forest Mycological Observatory (DFMO) will permit the study of those fungal communities which form the core group of saprophytic and mycorrhizal fungi in temperate forests. As a pilot project, plots representing a range of forest types will be surveyed in order to establish a baseline data set of basidiomycete diversity from the forest. Plots located within several long-term studies including the recently initiated Free-Air Carbon dioxide enrichment (FACE) experiment will next be studied. Early data from the FACE study indicate shifts in the microbial population in the soil, but as yet there have been no surveys of microbial diversity by FACE. Shifts in the abundance, activity and diversity of mycorrhizal fungi are particularly likely (in response to a greater supply of root exudates in the FACE plots) and may play an important role in long term forest/ecosystem health and stability. This study will develop a DNA-sequence database framework (based on ribosomal ITS sequences) linked with sites within the Duke Forest. Extensive molecular databases are already available for most fungal groups, making it possible to identify isolates to the genus in most instances and often to the species level. The focus will be on soil, litter and mycorrhizal samples from these sites, which will provide a more unbiased estimate of microbial diversity than estimates based 'above ground' sampling of fruit bodies or cultivable diversity. These data will then form a basis for the long term monitoring of fungal microbial diversity within the Duke Forest and FACE site. This project will provide baseline data about soil-inhabiting, mycorrhizal, soil, and litter-fungi from a variety of habitats. This project will also be one of the first studies of fungal community structure to assess the impacts of various environmental variables such as increases in carbon dioxide concentration on fungal diversity.