Foliar fungi of Betula pendula: impact of tree species mixtures and assessment methods

Abstract

Foliar fungi of silver birch (Betula pendula) in an experimental Finnish forest were investigated across a gradient of tree species richness using molecular high-throughput sequencing and visual macroscopic assessment. We hypothesized that the molecular approach detects more fungal taxa than visual assessment, and that there is a relationship among the most common fungal taxa detected by both techniques. Furthermore, we hypothesized that the fungal community composition, diversity, and distribution patterns are affected by changes in tree diversity. Sequencing revealed greater diversity of fungi on birch leaves than the visual assessment method. One species showed a linear relationship between the methods. Species-specific variation in fungal community composition could be partially explained by tree diversity, though overall fungal diversity was not affected by tree diversity. Analysis of specific fungal taxa indicated tree diversity effects at the local neighbourhood scale, where the proportion of birch among neighbouring trees varied, but not at the plot scale. In conclusion, both methods may be used to determine tree diversity effects on the foliar fungal community. However, high-throughput sequencing provided higher resolution of the fungal community, while the visual macroscopic assessment detected functionally active fungal species.

Forest die-off following global-change-type drought alters rhizosphere fungal communities

“…The workflow of this pipeline has been extensively detailed by Clemmensen et al (2015). We used the settings described by Nguyen et al (2017). Prior to clustering, all sequences were trimmed to 300 bp length and the primers removed.…”

“…Prior to clustering, all sequences were trimmed to 300 bp length and the primers removed. A clustering similarity of 98.5% was used, corresponding approximately to species level for ITS (Lindahl et al 2013, Ottosson et al 2015, Nguyen et al 2017. The most abundant genotype for each cluster was used to represent each operational taxonomic unit (OTU).…”

“…Potentially similar OTUs were aligned in Geneious to confirm identification. The relative abundance of each OTU per sample was determined from the sequence reads as the number of reads for an OTU divided by the total number of reads for the sample (Nguyen et al 2017).…”

Toward a methodical framework for comprehensively assessing forest multifunctionality

“…In contrast to the more common microscopic in‐depth investigation of fungal pathogens (Hantsch, Braun, Scherer‐Lorenzen, & Bruelheide, ; Hantsch, Bien, et al., ) or identification of foliar fungi with molecular high‐throughput sequencing (Nguyen et al., ), fungal damage assessment needs not only less time allowing a higher sample size, but also works without specific expertise about fungal species.…”

“…Parasitic interactions between plant hosts and fungal pathogens often cause a reduction in individual plant fitness by fungal consumption of photosynthetic products and negatively affect photosynthesis rates (Alves, Guimarães, Chaves, DaMatta, & Alfenas, 2011;Berger, Sinha, & Roitsch, 2007;Mitchell, 2003 In contrast to the more common microscopic in-depth investigation of fungal pathogens (Hantsch, Braun, Scherer-Lorenzen, & Bruelheide, 2013;Hantsch, Bien, et al, 2014) or identification of foliar fungi with molecular high-throughput sequencing (Nguyen et al, 2017), fungal damage assessment needs not only less time allowing a higher sample size, but also works without specific expertise about fungal species.…”