Long-term nitrogen and sulfur deposition increased root-associated pathogen diversity and changed mutualistic fungal diversity in a boreal forest

Yingtong Wu, Department of Biology, University of Missouri, St. Louis, St. Louis, MO, Jin-hyeob Kwak, Jeonbuk National University, Jeonju, Korea, Republic of (South), Justine Karst and Scott X. Chang, Department of Renewable Resources, University of Alberta, Edmonton, AB, Canada, Ming Ni, Département de Biologie, Sherbrooke University, Sherbrooke, QC, Canada, Yifan Yan, Wine Research Centre, University of British Columbia, Vancouver, BC, Canada, Xiaofei Lv and Jianming Xu, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China

Background/Question/Methods



Anthropogenic nitrogen (N) and sulfur (S) deposition can change above- and belowground biodiversity, including root-associated fungi that are tightly linked to plant fitness. We investigated the effect of eleven years of N and S addition on the diversity of root-associated fungal pathogens and mutualists, including ectomycorrhizal fungi (EMF), dark septate endophytes (DSEs), and ericoid mycorrhizal fungi (ERM), in a broadleaf tree-dominated boreal forest using HiSeq sequencing of ITS2 amplicons of root fungal DNA.



Results/Conclusions
Long-term N and S addition increased the diversity of root-associated pathogens, notably the abundance of Venturia macularis, which causes aspen leaf and shoot blight, in the forest floor. Nitrogen addition increased the abundance of several N-sensitive EMF taxa and of EMF related to organic-N uptake from the soil, but had little effect on the overall abundance and diversity of EMF. Nitrogen and S addition did not affect the abundance and diversity of DSEs, but N addition decreased the Shannon diversity and evenness of ERM communities in the mineral soil. The changed diversity of root-associated fungal pathogens and mutualists suggests that long-term N and S addition will impact the host plant's capacity for nutrient acquisition and defense against pathogens in the broadleaf-dominated boreal forest.