Fig 1.
A. thaliana development in the presence of O. maius.
(a) A. thaliana control plants (C) and A. thaliana-O. maius co-cultures (Om) 30 days after inoculation; (b) plant biomass measurements (roots—grey bars—and aboveground portions—open bars) in the presence (Om)/absence (C) of O. maius. Note the strong plant biomass increase in the presence of the fungus; (c) A. thaliana-O. maius co-cultures 30 days after inoculation: the fungus was previously grown on cellulose nitrate disks which were then placed on A. thaliana roots fungus side up (indirect contact—Om-IC) or fungus side down (direct contact—Om-DC); (d) plant biomass measurements (roots—grey bars—and aboveground portions—open bars) in the presence/absence of O. maius in indirect/direct contact with plant roots. Note the strong plant biomass increase in the presence of the fungus in both conditions and especially in the direct contact one. All pictures were taken at the same magnification. Bars represent the mean ±SD, n = 5 (each biological replicate represents the total biomass of 5 A. thaliana seedlings grown in an individual plate). Statistically significant differences (P<0.05) among treatments are indicated by asterisks or by different letters above the bars.
Fig 2.
A. thaliana development in the presence of O. maius WT (Om) and of three O. maius mutants (OmΔGOGAT; OmΔMFS; OmΔSOD).
(a) Control plants (C) and plant-fungus co-cultures 30 days after inoculation (all pictures were taken at the same magnification) (b) Measurement of auxin quantity released in the culture medium by O. maius WT and by the three O. maius mutants, using the Salkowski reaction [46]. Auxin quantity measured was normalized to the mycelium biomass. Bars represent the mean ±SD, n = 3 (each biological replicate represents the total biomass of 5 A. thaliana seedlings grown in an individual plate). Statistically significant differences (P<0.05) among treatments are indicated by different letters above the bars.
Fig 3.
Analysis of A. thaliana root development.
Average quantification of root parameters in 20 individual A. thaliana plants grown alone or co-cultured for 9 days with the O. maius WT strain (Om) or the O. maius GOGAT mutant (OmΔGOGAT) is plotted into charts. Primary (PR), secondary (SRs) and tertiary roots (TRs) were counted and measured using the ImageJ plug in SmartRoot software. A diagrammatic representation of A. thaliana root development in the different conditions tested is also shown.
Fig 4.
O. maius—A. thaliana co-cultivation experiments in the tripartite plate system.
(a) Control plants and plant-fungus co-culture 15 days after inoculation; (b) same as in (a) but plates were added with a VOC trap (activated charcoal, AC) in the third compartment; (c) same as in (a) but plates were added with a CO2 trap [Ba(OH)2*8H2O, B] together with two dental rolls in the third compartment; (d) plant biomass measurements (roots—grey bars—and aboveground portions—open bars) in the presence/absence of the fungus and of the trap compounds. Note the strong plant biomass increase in the presence of O. maius in all the conditions tested. Bars represent the mean ±SD, n = 5 (each biological replicate represents the total biomass of 3 A. thaliana seedlings grown in an individual plate). Statistically significant differences (P<0.05) among treatments are indicated by different letters above the bars.
Fig 5.
VOC emission profiles of the O. maius WT and of the O. maius GOGAT mutant.
VOCs were collected in the headspace of culture plates 15 (open and hatched bars) and 30 (black and dotted bars) days after inoculation. Bars represent the mean ±SD as pmol cm-2 h-1, n = 6. (OCT) 1-octen-3-ol; (CAD) epsilon-cadinene; (PHE) phenol,2,4-bis(1,1-dimethylethyl); (GER) germacrene D.
Fig 6.
A. thaliana development in the presence of O. maius and of nine other fungi.
(a) Control plants (C) and plant-fungus co-cultures 30 days after inoculation; (b) plant biomass measurements (roots—grey bars—and aboveground portions—open bars) in the presence/absence of fungi. Note the strong plant biomass increase in the presence of some of the fungi tested. Bars represent the mean ±SD, n = 5 (each biological replicate represents the total biomass of 5 A. thaliana seedlings grown in an individual plate). Statistically significant differences (P<0.05) among treatments are indicated by different letters above the bars. Om, Oidiodendron maius; Mb, Meliniomyces bicolor; Mv, Meliniomyces variabilis; Re, Rhizoscyphus ericae; Lb, Laccaria bicolor; Sl, Suillus luteus; Cg, Cenococcum geophilum; Tc, Tulasnella calospora; Ch, Cladosporium herbarum; Tv, Trametes versicolor.
Fig 7.
A. thaliana development in the presence of different fungi in the bipartite plate system.
(a) Control plants and plant-fungus co-cultures 15 days after inoculation; (b) plant biomass measurements (roots—grey bars—and aboveground portions—open bars) in the presence/absence of fungi. Note the strong plant biomass increase in the presence of some of the fungi tested. Bars represent the mean ±SD, n = 5 (each biological replicate represents the total biomass of 3 A. thaliana seedlings grown in an individual plate). Statistically significant differences (P<0.05) among treatments are indicated by different letters above the bars. Om, Oidiodendron maius; Mb, Meliniomyces bicolor; Mv, Meliniomyces variabilis; Re, Rhizoscyphus ericae; Lb, Laccaria bicolor; Cg, Cenococcum geophilum; Sl, Suillus luteus; Tc, Tulasnella calospora; Tv, Trametes versicolor; Ch, Cladosporium herbarum.