Table 1.
Fungal strains investigated in this study.
Fig 1.
The colonization patterns observed in Norway spruce (Picea abies) and European blueberry (Vaccinium myrtillus) roots in Experiment 1.
1a) Typical ericoid mycorrhizal colonization formed by Rhizoscyphus ericae in blueberry roots (asterisks); stained with trypan blue, observed with DIC, bar = 25 μm. 1b) An intracellular microsclerotium formed by Phialocephala helvetica in a blueberry root (arrowhead); stained with trypan blue, observed with DIC, bar = 25 μm. 1c) Intracellular microsclerotia formed by P. helvetica in the vascular cylinder of a spruce root (arrowheads); observed with DIC, bar = 25 μm. 1d) A Hartig net formed within the spruce root cortex (arrows) and an extraradical sclerotium formed on the spruce root surface (asterisk) by Acephala macrosclerotiorum; observed with DIC, bar = 25 μm. 1e) Spruce root tips colonized by A. macrosclerotiorum with extraradical superficial sclerotia formed on the root surface (arrows); bar = 0.5 mm. 1f) Intracellular hyphal loops morphologically resembling ericoid mycorrhizae (asterisks) formed by A. macrosclerotiorum in blueberry roots; stained with trypan blue, observed with DIC, bar = 25 μm. 1g) Loose intracellular hyphal loops which may morphologically resemble ericoid mycorrhiza (asterisks) formed by Phialocephala glacialis in blueberry roots; stained with trypan blue, bar = 25 μm. 1h) Intracellular colonization of spruce root cortex by P. glacialis (arrowheads); bar = 25 μm.
Table 2.
Fungal structures observed in the roots of Norway spruce (Picea abies), silver birch (Betula pendula) and European blueberry (Vaccinium myrtillus) colonized by the tested fungal strains.
Fig 2.
The colonization patterns observed in European blueberry (Vaccinium myrtillus) roots in Experiment 2 and in silver birch in Experiment 3.
2a) Intracellular hyphal colonization resembling ericoid mycorrhiza formed by Acephala applanta AAP-1 in blueberry roots (asterisks). 2b) An early stage of the development of an intracellular microsclerotium formed by A. applanata AAP-1 in a blueberry root (arrowhead). 2c) An extraradical sclerotium formed on the surface of a blueberry root by A. applanata AAP-1 (arrow). 2d) A blueberry hair root colonized in a manner resembling ericoid mycorrhiza by Acephala macrosclerotiorum AMA-11 (asterisks). 2e) A detail of two blueberry rhizodermal cells intracellularly colonized by A. macrosclerotiorum AMA-11 in a manner resembling ericoid mycorrhiza (asterisks). 2f) An extraradical sclerotium formed on the surface of a blueberry root by A. macrosclerotiorum AMA-11 (arrow). Note accompanying intracellular hyphal colonization (arrowheads). 2g) A loose intracellular hyphal loop formed by A. macrosclerotiorum AMA-1 in a birch root (arrow). 2h) A melanised intracellular microsclerotium formed by Acephala applanata AAP-1 in birch (arrowhead). All figures stained with trypan blue, observed with DIC, bars = 25 μm.
Fig 3.
Percentage fungal colonization of blueberry rhizodermal cells in Experiment 2.
Blueberry seedlings were inoculated by 8 PAC species, 2 species related to PAC and Rhizoscyphus ericae as a positive control, two strains per each species. Blueberry seedlings were grown in a peat-based substrate for 3.5 months under in vitro conditions. The presented data are means of 6 replicates ± standard error of mean. Different letters above the columns indicate significant differences according to the non-parametric Kruskal-Wallis test followed by the multiple-comparison z-value test.
Fig 4.
The effect of inoculation on blueberry dry shoot weight in Experiment 2.
Blueberry seedlings were inoculated by 8 PAC species, 2 species related to PAC and Rhizoscyphus ericae as a positive control, two strains per each species. Blueberry seedlings were grown in a peat-based substrate for 3.5 months under in vitro conditions. The presented data are means of 6 replicates ± standard error of mean. Different letters above the columns indicate significant differences according to the non-parametric Kruskal-Wallis test followed by the multiple-comparison z-value test.
Fig 5.
The effect of inoculation on blueberry fresh root weight in Experiment 2.
Blueberry seedlings were inoculated by 8 PAC species, 2 species related to PAC and Rhizoscyphus ericae as a positive control, two strains per each species. Blueberry seedlings were grown in a peat-based substrate for 3.5 months under in vitro conditions. The presented data are means of 6 replicates ± standard error of mean. Different letters above the columns indicate significant differences according to the non-parametric Kruskal-Wallis test followed by the multiple-comparison z-value test.
Table 3.
Colonization, root fresh weight and shoot dry weight of birch seedlings inoculated by two strains of A. macrosclerotiorum, one strain of A. applanata and one strain of P. involutus as a positive EcM control fungus in Experiment 3.
Fig 6.
Relative abundances of the dominant fungal orders in Ericaceae roots detected by pyrosequencing.
Tag-encoded pyrosequencing was performed with ten Ericaceae hair roots samples from three sites in NP České Švýcarsko (CS1—five samples, CS2—three samples, CS3—two samples) where the ectomycorrhizal morphotype Pinirhiza sclerotina formed by the DSE fungus related to PAC Acephala macrosclerotiorum was present. The obtained data were processed as described in Materials and Methods. OTUs with lower similarity and coverage than 88% were assigned as non-identified together with incertae sedis species. Orders less abundant than 0.1% were excluded from the figure.
Fig 7.
Values of Chao-1 index in equally resampled localities.
The values of Chao-1 indexes for the respective localities are as follows: CS1-1 = 51, CS1-2 = 40.3, CS1-3 = 42.5, CS1-4 = 65.6, CS1-5 = 33, CS2-1 = 22, CS2-2 = 63, CS2-3 = 61, CS3-1 = 59 and CS3-2 = 45.5.
Fig 8.
Principal component analysis of the relative abundance of OTUs.
Only OTUs with component loadings for the first or second axis higher than 0.015 were visualized. For detailed information about the respective OTUs see S2 Table.