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Defence chemistry modulation by light and temperature shifts and the resulting effects on associated epibacteria of Fucus vesiculosus.

Saha M, Rempt M, Stratil SB, Wahl M, Pohnert G, Weinberger F - PLoS ONE (2014)

Bottom Line: Altogether, the effect of different treatment levels upon defence compound concentrations was limited.Nonetheless, in both experiments along with the direct influence of temperature and light, all three compounds apparently affected the overall bacterial community composition associated with F. vesiculosus since tendencies for insensitivity towards all three compounds were observed among bacterial taxa that typically dominate those communities.Given that the concentrations of at least one of the compounds (in most cases DMSP) were always high enough to inhibit bacterial settlement, we conclude that the capacity of F. vesiculosus for such defence will hardly be compromised by shading or warming to temperatures up to 25°C.

View Article: PubMed Central - PubMed

Affiliation: Department of Benthic Ecology, Helmholtz-Zentrum für Ozeanforschung (GEOMAR), Kiel, Germany.

ABSTRACT
The goals of this study were (1) to investigate whether Fucus vesiculosus regulates the production of its antifouling defence chemicals against epibacteria in response to light limitation and temperature shifts and (2) to investigate if different surface concentrations of defence compounds shape epibacterial communities. F. vesiculosus was incubated in indoor mesocosms at five different temperature conditions (5 to 25°C) and in outdoor mesocosms under six differently reduced sunlight conditions (0 to 100%), respectively. Algal surface concentrations of previously identified antifouling compounds--dimethylsulphopropionate (DMSP), fucoxanthin and proline--were determined and the bacterial community composition was characterized by in-depth sequencing of the 16S-rRNA gene. Altogether, the effect of different treatment levels upon defence compound concentrations was limited. Under all conditions DMSP alone appeared to be sufficiently concentrated to warrant for at least a partial inhibitory action against epibiotic bacteria of F. vesiculosus. In contrast, proline and fucoxanthin rarely reached the necessary concentration ranges for self-contained inhibition. Nonetheless, in both experiments along with the direct influence of temperature and light, all three compounds apparently affected the overall bacterial community composition associated with F. vesiculosus since tendencies for insensitivity towards all three compounds were observed among bacterial taxa that typically dominate those communities. Given that the concentrations of at least one of the compounds (in most cases DMSP) were always high enough to inhibit bacterial settlement, we conclude that the capacity of F. vesiculosus for such defence will hardly be compromised by shading or warming to temperatures up to 25°C.

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Variation of surface DMSP, proline and fucoxanthin concentration, respectively in F. vesiculosus treated under different temperature and light conditions for 28 d and 18 d, respectively.Different letters indicate different temperature and light treatment responses in compound concentration (Tukey's test P<0.05). Median (central symbol), n = 5 (n = 4 for fucoxanthin measurement at 10°C), interquartile range.
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pone-0105333-g001: Variation of surface DMSP, proline and fucoxanthin concentration, respectively in F. vesiculosus treated under different temperature and light conditions for 28 d and 18 d, respectively.Different letters indicate different temperature and light treatment responses in compound concentration (Tukey's test P<0.05). Median (central symbol), n = 5 (n = 4 for fucoxanthin measurement at 10°C), interquartile range.

Mentions: In the temperature experiment, healthy apical branches exhibited, on average, surface concentrations of DMSP and proline ranging from 0.16 to 0.96 ng cm−2 and from 0.004 to 0.01 ng cm−2, respectively. Fucoxanthin concentrations ranged from 18 to 400 ng cm−2. However, there was often considerable variability of concentrations within treatment levels (Figs. 1(i) to (iii)). Nonetheless, the surface DMSP concentration also varied moderately between temperature levels (1-way ANOVA, F = 3, p = 0.03) and was higher at 20°C than at 25°C (Tukey's HSD test, p<0.05, Fig. 1(i)). The surface proline concentration did not vary significantly with temperature (1-way ANOVA, p = 0.05, Fig. 1 (ii)), however it tended to decrease with warming. In contrast, the fucoxanthin surface concentration increased significantly with temperature (1-way ANOVA, F = 42, p<0.001, Fig. 1 (iii)), with a five-fold increase between 20°C and 25°C (Table 1, Fig. 1 (iii)).


Defence chemistry modulation by light and temperature shifts and the resulting effects on associated epibacteria of Fucus vesiculosus.

Saha M, Rempt M, Stratil SB, Wahl M, Pohnert G, Weinberger F - PLoS ONE (2014)

Variation of surface DMSP, proline and fucoxanthin concentration, respectively in F. vesiculosus treated under different temperature and light conditions for 28 d and 18 d, respectively.Different letters indicate different temperature and light treatment responses in compound concentration (Tukey's test P<0.05). Median (central symbol), n = 5 (n = 4 for fucoxanthin measurement at 10°C), interquartile range.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4215838&req=5

pone-0105333-g001: Variation of surface DMSP, proline and fucoxanthin concentration, respectively in F. vesiculosus treated under different temperature and light conditions for 28 d and 18 d, respectively.Different letters indicate different temperature and light treatment responses in compound concentration (Tukey's test P<0.05). Median (central symbol), n = 5 (n = 4 for fucoxanthin measurement at 10°C), interquartile range.
Mentions: In the temperature experiment, healthy apical branches exhibited, on average, surface concentrations of DMSP and proline ranging from 0.16 to 0.96 ng cm−2 and from 0.004 to 0.01 ng cm−2, respectively. Fucoxanthin concentrations ranged from 18 to 400 ng cm−2. However, there was often considerable variability of concentrations within treatment levels (Figs. 1(i) to (iii)). Nonetheless, the surface DMSP concentration also varied moderately between temperature levels (1-way ANOVA, F = 3, p = 0.03) and was higher at 20°C than at 25°C (Tukey's HSD test, p<0.05, Fig. 1(i)). The surface proline concentration did not vary significantly with temperature (1-way ANOVA, p = 0.05, Fig. 1 (ii)), however it tended to decrease with warming. In contrast, the fucoxanthin surface concentration increased significantly with temperature (1-way ANOVA, F = 42, p<0.001, Fig. 1 (iii)), with a five-fold increase between 20°C and 25°C (Table 1, Fig. 1 (iii)).

Bottom Line: Altogether, the effect of different treatment levels upon defence compound concentrations was limited.Nonetheless, in both experiments along with the direct influence of temperature and light, all three compounds apparently affected the overall bacterial community composition associated with F. vesiculosus since tendencies for insensitivity towards all three compounds were observed among bacterial taxa that typically dominate those communities.Given that the concentrations of at least one of the compounds (in most cases DMSP) were always high enough to inhibit bacterial settlement, we conclude that the capacity of F. vesiculosus for such defence will hardly be compromised by shading or warming to temperatures up to 25°C.

View Article: PubMed Central - PubMed

Affiliation: Department of Benthic Ecology, Helmholtz-Zentrum für Ozeanforschung (GEOMAR), Kiel, Germany.

ABSTRACT
The goals of this study were (1) to investigate whether Fucus vesiculosus regulates the production of its antifouling defence chemicals against epibacteria in response to light limitation and temperature shifts and (2) to investigate if different surface concentrations of defence compounds shape epibacterial communities. F. vesiculosus was incubated in indoor mesocosms at five different temperature conditions (5 to 25°C) and in outdoor mesocosms under six differently reduced sunlight conditions (0 to 100%), respectively. Algal surface concentrations of previously identified antifouling compounds--dimethylsulphopropionate (DMSP), fucoxanthin and proline--were determined and the bacterial community composition was characterized by in-depth sequencing of the 16S-rRNA gene. Altogether, the effect of different treatment levels upon defence compound concentrations was limited. Under all conditions DMSP alone appeared to be sufficiently concentrated to warrant for at least a partial inhibitory action against epibiotic bacteria of F. vesiculosus. In contrast, proline and fucoxanthin rarely reached the necessary concentration ranges for self-contained inhibition. Nonetheless, in both experiments along with the direct influence of temperature and light, all three compounds apparently affected the overall bacterial community composition associated with F. vesiculosus since tendencies for insensitivity towards all three compounds were observed among bacterial taxa that typically dominate those communities. Given that the concentrations of at least one of the compounds (in most cases DMSP) were always high enough to inhibit bacterial settlement, we conclude that the capacity of F. vesiculosus for such defence will hardly be compromised by shading or warming to temperatures up to 25°C.

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