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Basidiomycete yeasts in the cortex of ascomycete macrolichens

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Science  29 Jul 2016:
Vol. 353, Issue 6298, pp. 488-492
DOI: 10.1126/science.aaf8287
  • Fig. 1 Genome-wide divergence and transcript abundance of fungi and algae, based on symbiont subsets extracted from wild Bryoria metatranscriptomes.

    (A and B) Unrooted maximum likelihood topologies for (A) the Ascomycota member (lecanoromycete) and (B) the Viridiplantae member (alga) within the lichen pair B. fremontii and B. tortuosa, based on 30,001 and 25,788 SNPs, respectively. Numbers refer to metatranscriptome sample IDs (table S2). Scale bars indicate the average number of substitutions per site (C to E) Logarithm of the fold change (logFC) between vulpinic acid–deficient (B. fremontii) and vulpinic acid–rich (B. tortuosa) phenotypes in 15 Bryoria metatranscriptomes, plotted against transcript abundance (logCPM, logarithm of counts per million reads). Only transcripts found in all 15 samples were included. Ascomycota transcripts only are shown in (C). All fungal transcripts are shown in (D), with taxonomic assignments superimposed; a plot with statistically significant transcript differential abundance is shown as an inset. Viridiplantae transcripts are shown in (E). Red dots indicate a log fold change with P < 0.05 in (C), the inset of (D), and (E) (highlighted with arrows).

  • Fig. 2 Placement of Cyphobasidiales members and their diversity within lichens.

    (A) Maximum likelihood phylogenomic tree based on 39 fungal proteomes and 349 single-copy orthologous loci. Dating based on a 58-locus subsample shows relative splits between Cyphobasidiales and Cystobasidium minutum and splits leading to the lecanoromycete genera Xanthoria, Cladonia, and Bryoria (colored bars indicate 95% confidence intervals; fungi occurring in lichens are shown in green). (B) Maximum likelihood rDNA phylogeny of the class Cystobasidiomycetes, with images of representative lichen species from which sequences were obtained in each clade; thick branches indicate bootstrap support >70%. Shaded triangles are scaled to the earliest branch splits of underlying sequence divergence in each clade. Full versions of the trees are shown in fig. S3.

  • Fig. 3 Differential abundance of Cyphobasidiales yeasts in B. fremontii and B. tortuosa.

    (A) B. fremontii, with (B) few FISH-hybridized live yeast cells at the level of the cortex. (C) B. tortuosa, with (D) abundant FISH-hybridized cortical yeast cells (scale bars, 20 μm).

  • Fig. 4 Fluorescent cell imaging of dual fungal elements in lichen thalli.

    (A) Scanning electron microscopy image of a thallus filament of B. capillaris (scale bar, 200 μm). (B) FISH hybridization of B. capillaris thallus, showing Cyphobasidiales yeasts (green) and the lecanoromycete (blue) with algal chlorophyll A autofluorescence (red). The volume within the two vertical lines is visualized on the right; the unclipped frontal view is shown at the top. Movie S2 shows an animation of the three-dimensional ~100-μm z-stack. (C) Detail of yeast cells (scale bar, 5 μm).

  • Basidiomycete yeasts in the cortex of ascomycete macrolichens

    Toby Spribille, Veera Tuovinen, Philipp Resl, Dan Vanderpool, Heimo Wolinski, M. Catherine Aime, Kevin Schneider, Edith Stabentheiner, Merje Toome-Heller, Göran Thor, Helmut Mayrhofer, Hanna Johannesson, John P. McCutcheon

    Materials/Methods, Supplementary Text, Tables, Figures, and/or References

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    • Materials and Methods
    • Figs. S1 to S16
    • Tables S1 to S12
    • Full Reference List
    • Captions for Movies S1 and S2
    Table S6
    Table S7

    Images, Video, and Other Media

    Movie S1
    Animation of a ~ 15 μm 3D z-stack through the cortex region of a fluorescently labeled thallus of Bryoria tortuosa. Secondary metabolite (vulpinic acid) residues autofluoresce in the same channel as the CY3-labeled ascomycete (purple), while 6-FAM-labeled Cyphobasidiales (basidiomycete) yeasts are rendered in green. Algae are located below and out of view of the z-stack.
    Movie S2
    Animation of a ~100 μm 3D z-stack through a fluorescently hybridized thallus of Bryoria capillaris. Cyphobasidiales (basidiomycete) yeasts are rendered in green, lecanoromycete (ascomycete) filamentous fungi are rendered in purple, and algae (Trebouxia simplex) are rendered in red.