Responses of Gymnosperm Bark Tissues to Fungal Infections

Woodward, Stephen

doi:10.1007/978-3-662-01642-8_4

Cited by 37 publications

(44 citation statements)

References 41 publications

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“…These results agree with those of Woodward and Pearce (1988a), Lindberg et al (1992) and Brignolas et al (1995), all of whom observed similar changes a few days after fungal infection. It is known that the β-glycosidase enzymes produced by pathogens, rather than the constitutive host enzymes, are able to metabolize stilbene glycosides to the corresponding aglycones (Johansson and Stenlid 1985;Woodward and Pearce 1988a;Woodward 1992). In this study the increase in β-glycosidase activities in fungus-inoculated phloem might also have been instrumental in the release of aglycones from glycosides (Fig.…”

Section: Terpenesmentioning

confidence: 75%

“…The lesion surrounding the attacked site is impregnated with secondary metabolites, i.e. phenolic and terpenoid compounds, and isolated by the formation of wound periderm, callus tissue and traumatic resin cavities at the cambium-sapwood interface (Reid et al 1967;Berryman 1969;Woodward andPearce 1988a, 1988b;Delorme and Lieutier 1990). The codeterminants of conifer resistance to bark beetle-fungus attack have been tentatively identified as the primary, or resident, resin canal system and the hypersensitive reaction, which functions as wound cleansing, containment of infection and wound healing (Berryman 1972).…”

Section: Introductionmentioning

confidence: 99%

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Induced responses in stilbenes and terpenes in fertilized Norway spruce after inoculation with blue-stain fungus, Ceratocystis polonica

Viiri

Annila²,

Kitunen³

et al. 2001

Trees

102

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In conifers, attacks by bark beetles and associated pathogenic fungi cause an induced wound response, which is characterized by accumulation of antifungal compounds and morphological changes that aid wound healing. In this article the stilbene and terpene concentrations of Norway spruce phloem were monitored as symptoms of induced wound responses in relation to changed nutrient conditions caused by fertilization. Plots of mature Norway spruce were fertilized with N, P or NPK. One year after fertilization the trees were artificially infected with Ceratocystis polonica, a pathogenic fungus associated with the bark beetle Ips typographus. The response of stilbenes to fungal inoculation was mainly qualitative. The concentration of stilbene glycosides in the phloem decreased, and in the immediate vicinity of the site of fungal inoculation, stilbene glycosides were less frequent than in mechanically wounded or unwounded phloem. Corresponding stilbene aglycones were most frequent inside the reaction lesion. The concentration of total stilbene aglycones near the inoculation site was significantly lower in N-fertilized trees than in unfertilized trees. Fungal inoculation caused a strong quantitative response in terpenes. The total terpene concentration of the phloem increased significantly, to almost 100 times greater near the inoculation site compared to the constitutive values. N fertilization significantly reduced the total terpene and total stilbene aglycone concentrations near the inoculation sites. Thus, N fertilization may reduce the ability of Norway spruce to defend itself against fungal pathogens.

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Section: Terpenesmentioning

confidence: 75%

Section: Introductionmentioning

confidence: 99%

Induced responses in stilbenes and terpenes in fertilized Norway spruce after inoculation with blue-stain fungus, Ceratocystis polonica

Viiri

Annila²,

Kitunen³

et al. 2001

Trees

102

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“…W'oodward, 1992), but a consensus suggests that resinous exudates can provide an effective defence mechanism (Hillis. 1987;Woodward. 1992), How-ever, instances where resin accumulation does not appear to contribute to defence are well documented (e.g.…”

Section: Bark-the First Line Of Defencementioning

confidence: 99%

Antimicrobial defences in the wood of living trees

1996

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summary The wood (xylem) in a living tree is protected from microbial attack by the secondary plant surface (periderm and rhytidome), which provides an effective barrier preventing the entry of most potential pathogens, and by constitutive and induced defence mechanisms in the bark (cortex and phloem). Although a few pathogens are able To penetrate these outer tissues directly, most xylem pathogens gain entry through wounds that expose this tissue and render it more vulnerable to attack. In functional sapwood, microbial colonization might be restricted by active defence mechanisms, or by passive microenvironmental restriction consequent upon the high water content and low availability of O2 in healthy conductive xylem. These factors are not mutually exclusive: indeed, they may operate in concert in many host‐pathogen interactions. Sapwood lesions made by wood‐decaying fungi are characteristically bounded by multiccllular walls OT barrier zones (compartmentalization wall 4 barriers and reaction zones (column boundary layers)), which may function both as inhibitory or degradation‐resistant barriers to further pathogen spread, and as seals to maintain xylem function and prevent the drying and aeration that could predispose to further infection. A range of putative antimicrobial defence mechanisms contributing to the effectiveness of such barriers has been identified in sapwood tissues. This includes cell wall alterations, constitutive and induced antimicrobial compounds, necrotic responses of living cells and the deposition of gummy materials, often resinous or polyphenolic, at the host‐pathogen interface. Nutritional, environmental and anatomical features of living wood might also contribute to pathogen restriction. Although there might be differences in detail, the defences operating in gymnospenns and angiosperms are generally similar. Defence responses against a variety of pathogen categories also have much in common. Dynamic studies are crucial in elucidating the roles of the various components of the host‐pathogen interaction in the wood of living trees. A model for the protection and defence of xylem tissues in woody angiosperms is suggested, based largely upon results from dynamic studies of host‐pathogen interactions in the wood of sycamore (Acer pseudoplatanus L.).

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“…Ces substances peuvent être des polymères (tanins) ou des molécules de faible poids moléculaire (flavonoïdes, stilbènes, lignanes, terpénoïdes). Le spectre d'action de ces dernières est plus large et elles sont potentiellement plus toxiques que les précédentes [85].…”

Section: Introductionunclassified

Caract�risation et origine des tropolones responsables de la durabilit� naturelle des Cupressac�es. Application potentielle en pr�servation du bois

Haluk

Roussel

2000

Ann. For. Sci.

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Résumé -L'objectif de cette revue est de présenter la nature chimique d'une famille de composés extractibles appelée tropolones, répertoriée dans l'ordre des Cupressales et considérée comme étant responsable de la durabilité naturelle des essences contenant ces métabolites secondaires. Des tropolones, en particulier les α, β et γ-thujaplicines, ont souvent été isolées à partir de Cupressacées (Cupressus, Chamaecyparis, Juniperus, Thuja, …) qui possèdent en effet un bois très résistant à la biodégradation. Des études déjà anciennes ont montré la toxicité importante des tropolones vis-à-vis des champignons de la pourriture du bois et des insectes. Il serait donc intéressant de pouvoir exploiter cette propriété au niveau industriel en substituant les agents chimiques de préservation du bois (CCA, etc.) par des molécules naturelles biocides. Ce concept peut donc constituer un enjeu prometteur pour le respect de l'environnement. Comme l'extraction de ces substances par des méthodes habituelles (solvant, CO 2 supercritique) ou leur synthèse chimique, onéreuse et peu rentable, ne sont pas envisageables au niveau industriel, l'exploitation des biotechnologies végétales (cals, suspensions cellulaires) peut constituer une démarche judicieuse pour l'obtention rapide de ces molécules biocides. En effet, la biosynthèse des tropolones a été obtenue par culture cellulaire de Thuja plicata et des premiers essais d'imprégnation d'éprouvettes de bois avec un extrait brut obtenu à partir des cellules végétales tendent à confirmer l'efficacité antifongique de ce nouveau type de traitement de préservation du bois.tropolones / Cupressacées / durabilité naturelle / préservation du bois / biotechnologies végétales Abstract -Characterization and origin of tropolones responsible for the cupressales natural durability. Potential application to wood preservation. The aim of this review is to present the chemical structure of a group of compounds naturally found in the trees belonging to the Order of the Cupressales, and being considered responsible for this wood species natural durability: namely tropolones. These compounds, and particularly the α, β and γ-thujaplicin, have often been isolated from Cupressaceae (Cupressus, Chamaecyparis, Juniperus, Thuja, …), which timber is extremely resistant to biodegradation. Previous studies have shown the important inhibition properties of the tropolones towards wood-destroying fungi and insects. Then, it would be an environmental and safety challenge to use these properties at an industrial scale, as a substitution to the toxic wood preservatives (such as CCA). However, either the extraction of these molecules (solvent extraction, CO 2 supercritical fluid, …) or their synthesis are far too expensive for such an application. The use of biotechnologies (cals, cell suspensions, …) could be judicious solution to get a cost-effective production of tropolones. Biosynthesis of tropolones from cell cultures of Thuja plicata has already been assessed, and first wood impregnation trials with crude extracts ha...

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Responses of Gymnosperm Bark Tissues to Fungal Infections

Cited by 37 publications

References 41 publications

Induced responses in stilbenes and terpenes in fertilized Norway spruce after inoculation with blue-stain fungus, Ceratocystis polonica

Induced responses in stilbenes and terpenes in fertilized Norway spruce after inoculation with blue-stain fungus, Ceratocystis polonica

Antimicrobial defences in the wood of living trees

Caract�risation et origine des tropolones responsables de la durabilit� naturelle des Cupressac�es. Application potentielle en pr�servation du bois

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