Fig 1.
Assays to characterize wood-decay abilities.
(A) Incubation periods of D. seriata, E. lata, F. polymorpha, and N. parvum, during in vitro assays (enzyme quantification, enzyme detection, phenolic assays, and wood block decay). (B) Steps of wood block-decay assays, showing when samples were collected for microscopy, re-isolation, and quantitation of dry-weight loss and percentages (dry weight) of cell-wall components (lignin, pectin, α-cellulose, and hemicellulose) remaining.
Table 1.
Percent dry weight loss and percent dry weight remaining of cell-wall components (lignin, pectin, cellulose, and hemicellulose) at 6 months post-inoculation of Vitis vinifera ‘Merlot’ wood blocks inoculated with D. seriata, N. parvum, E. lata, and F. polymorpha, versus a non-inoculated control. Values represent the means of 20 blocks per inoculation treatment (95% confidence limits are shown in parentheses). Means with different letters within a column are significantly different (Tukey’s test, P ≤ 0.05).
Fig 2.
Localization of hyphae in wood blocks, at 6 months post-inoculation.
(A) Transverse section of non-inoculated wood block, with hyphae absent from xylem fibers (F), rays (R), and vessels (V). (B) Transverse section of non-inoculated wood block, with hyphae absent from xylem rays (R) and fibers. (C) Longitudinal section of ray parenchyma extensively colonized by hyphae (^) of D. seriata and parenchyma cell walls visibly damaged/deteriorated. (D) Transverse section with hyphae of D. seriata localized in fibers and rays. (E) Longitudinal section of pith parenchyma and bordering fibers colonized by hyphae of N. parvum. (F) Transverse section of ray and fiber lumens colonized by hyphae of N. parvum. (G) Transverse section of fibers and rays colonized by hyphae of E. lata. (H) Longitudinal section of fibers and a vessel colonized by hyphae of F. polymorpha. (I) Transverse section of fibers colonized by hyphae of F. polymorpha, which span cell walls of two adjacent fibers (*).
Fig 3.
Percentage of fungal-growth induction (> 0) or inhibition (< 0) by nine wood components.
Timepoints are 3 days (‘early’) for D. seriata, E. lata, and N. parvum, and 6 days (‘early’) for F. polymorpha. Fungi were grown on solid minimal medium amended with each wood component, compared to an unamended control (Enzyme-detection assay, Fig 1A). Each bar is the difference in mean colony diameters of 12 amended plates versus 12 unamended plates per fungus, pooled across two replicate experiments. Bars with an asterisk represent significant larger mean colony diameters (> 0) or smaller mean colony diameters (< 0) on amended versus unamended media (T test, P ≤ 0.05). Bars with no asterisk represent no statistically significant effect of the wood component on fungal growth.
Fig 4.
Mean colony diameter (solid line) and detection of enzyme activity (i.e., mean color-change diameter, dashed line).
Timepoints are 3 days (‘early’) for D. seriata, E. lata, and N. parvum, and 6 days (‘early’) for F. polymorpha. Fungi were grown on solid minimal medium amended with each wood component (Enzyme-detection assay, Fig 1A). No enzyme activity was detected in unamended controls. Values on the axes represent the mean-colony and color-change diameters of 12 plates per fungus, pooled across two replicate experiments (maximum value is 8.5 cm).
Fig 5.
Quantification of enzyme activity.
Timepoints are 2, 2, 3, or 7 days (‘early’) and 5, 5, 7, or 14 days (‘mid’), for D. seriata, E. lata, N. parvum, or F. polymorpha, respectively. Fungi were grown in liquid minimal medium amended with grapevine wood powder, compared to an unamended control (Enzyme-quantification assay, Fig 1A). Bars represent the mean of 20 tubes of amended media per fungus, pooled across two replicate experiments (no enzyme activity was detected in unamended controls). Error bars are 95% confidence limits. Means with different letters within a panel are significantly different (Tukey’s test, P ≤ 0.05).
Fig 6.
Percentage of fungal-growth induction (> 0) or inhibition (< 0) by four phenolic compounds.
Timepoints are: (A) 2 or 3 days (‘early’), (B) 5 or 7 days (‘mid’), and (C) 15 or 21 days (‘late’) for D. seriata and N. parvum, or E. lata, respectively. Fungi were grown in liquid minimal medium amended with four phenolic compounds, compared to an unamended control (Phenolic assays, Fig 1A). Each bar is the difference in mean fungal biomass (fresh weight) of 12 amended tubes versus 12 unamended tubes per fungus, pooled across two replicate experiments. Bars with an asterisk represent significant larger mean fungal biomass (> 0) or smaller mean fungal biomass (< 0) on amended versus unamended media (T test, P ≤ 0.05). Bars with no asterisk represent no statistically significant effect of the phenolic compound on fungal growth.
Fig 7.
Phenolic compounds remaining in liquid minimal medium, after incubation.
Phenolic compounds are: (A) Piceid and the developed resveratrol derivative, (B) Rutin, (C) Epicatechin and a developed epicatechin derivative, and (D) Gallic acid. Timepoints are: 2 or 3 days (‘early’), 5 or 7 days (‘mid’), and 15 or 21 days (‘late’) for D. seriata and N. parvum, or E. lata, respectively. Fungi were grown in liquid minimal medium amended with four phenolic compounds, compared to non-inoculated control tubes with each phenolic compound (Phenolic assays, Fig 1A). Bars represent the mean of 12 tubes per fungus. Error bars are 95% confidence limits. Means with different letters within a panel are significantly different (Tukey’s test, P ≤ 0.05). Resveratrol was derived from elimination (by the fungi) of glucose from piceid.