Fig. 4

TEF metabarcoding assay outperforms ITS1 when detecting low level filamentous fungal species in mock communities. (A) Boxplot of percent abundance for species spiked at 2% within mock communities targeted by ITS1(left) or TEF (right). Expected percent abundance is indicated by dashed black line. The red dotted line indicates no identification. Percent abundance was significantly different between species for each target (P < 0.0001 by Kruskal-Wallis test). For each target, percent abundances are grouped by sequencing instrument. For those which were identified, excluding Lomentospora prolificans when targeted by ITS1, species level quantifications were not significantly different between instruments (ns, P < 0.05 by Wilcoxon rank sum test). Wilcoxon rank sum tests were not performed for species with less than 3 data points per human background status and are indicated with ‘ND’. (B) Heatmap representation of identification (ID) rates for species when spiked at 2% within mock communities. ITS1 failed to identify four filamentous fungi in any samples, and another five species had suboptimal ID rates. TEF identified all but one species in all samples tested. Sequencing instrument did not affect ID rates overall