Transcriptomic overview of root-associated fungal community structure in samples from NL and NE plots from the same forest site over a growing season. (A) Relative distribution of fungal reads observed per time point in NL and NE conditions. An asterisk (*) indicates significant difference between NL and NE (P < 0.001; two-tailed Wilcoxon signed-rank test). (B) Vector plot of the PCA of a fungal metatranscriptome based on samples collected at 19 time points over a growing season, in NL or NE soils. Each vector denotes the distance and orientation between the average of the NL replicates for a given time point (dot at the origin of the arrow), and those of the NE samples (point of the arrow). Weeks with active fertilization occurring have been indicated by a dotted vector. (C) The number of reads assigned to each fungal family were normalized to the total number of fungal reads present and the top 10 most represented fungal families in each treatment were identified (11 families in total), accounting for 98.7% of all fungal reads. The normalized read count of these 10 families were plotted across the sampling time course for both NL and NE conditions. The period of active fertilization has been indicated by dotted shading. (D) Shannon diversity index of fungal families in NL and NE forest plots. An asterisk (*) indicates significant difference between NL and NE (P < 0.001; two-tailed Wilcoxon signed-rank test). (E) PCA of fungal reads mapped to specific reference genomes (fungal species) in NL and NE conditions. The nine fungal species with the highest read representation are indicated. PC1 was largely attributable to the number of reads assigned to a specific species (86% variance explained) and was visualized using node size. Node color represents species identity and the colored line around each node indicates treatment, with green = NL, gold = NE. (F) Relative hierarchy of the 11 most represented fungal species in NL and NE, representing 49.9% of all fungal reads. An asterisk (*) indicates this species is not in the corresponding list in the opposing treatment.