| induced resistance to pathogenic fungi in norway spruce | norway spruce (picea abies) trees (approximately 16 m high) of a single clone were used to study the effects of fungal infection and wounding on induction of resistance to the bark beetle-associated bluestain fungus ceratocystis polonica. a dose-response experiment was designed involving three different dosages of fungal (fungus and wound) and sterile agar (wound) pretreatment inoculations (10, 50, or 100 inoculations/m(2) on the stem between 0.8 and 2.0 m high). three weeks after pretreatment, ... | 1999 | 10517848 |
| intra- and inter-provenance variability in phloem phenols of picea abies and relationship to a bark beetle-associated fungus. | one hundred norway spruce (picea abies (l.) karst.) clones (three ramets per clone) were analyzed for phloem phenol composition and concentration before and 10 days after wound inoculation with sterile malt agar. fifty clones (experiment 1) belonged to the same provenance, whereas the remaining clones (experiment 2) belonged to five provenances from three geographic areas. in experiment 2, two additional ramets from the same clones were mass inoculated with ceratocystis polonica (siem.) c. morea ... | 2003 | 12566260 |
| inducible anatomical defense responses in norway spruce stems and their possible role in induced resistance. | norway spruce (picea abies (l.) karst.) trees were preinoculated with a sublethal dose of the blue-stain fungus ceratocystis polonica siem. (c. moreau) 1 to 52 weeks before they were mass inoculated with the same fungus. trees pretreated 1 week before mass inoculation had similar, severe symptoms of fungal infection as the control trees. pretreatment 3, 6 or 9 weeks before mass inoculation resulted in effective protection of the trees, reducing pathogenic symptoms by 63-90% relative to the contr ... | 2003 | 12566269 |
| mechanical injury and fungal infection induce acquired resistance in norway spruce. | norway spruce trees (picea abies (l.) karst.) pretreated by wounding and fungal infection showed highly enhanced resistance to a subsequent challenge inoculation with the pathogenic bluestain fungus ceratocystis polonica (siem.) c. moreau. this is the first time the effectiveness of the constitutive and inducible defenses has been shown to depend on prior wounding and infection in conifers, although such acquired resistance has previously been found in several angiosperms. trees that were pretre ... | 1999 | 12651562 |
| the putative gymnosperm plant defensin polypeptide (spi1) accumulates after seed germination, is not readily released, and the spi1 levels are reduced in pythium dimorphum-infected spruce roots. | the putative plant defensin spi1 cdna from the conifer norway spruce (picea abies) is the only known plant defensin-like sequence from a gymnosperm. the predicted translational product spi1 was not detected in the embryo or other parts of the seed by means of antibodies, but it accumulated in the root cortex after germination. in roots of seedlings infected with the root pathogenic oomycete pythium dimorphum and the blue stain fungus ceratocystis polonica, variable levels of spi1 was detected du ... | 2003 | 12856937 |
| induced responses to pathogen infection in norway spruce phloem: changes in polyphenolic parenchyma cells, chalcone synthase transcript levels and peroxidase activity. | polyphenolic parenchyma cells (pp cells) in norway spruce (picea abies (l.) karst.) stem phloem play important roles in constitutive and inducible defenses. to determine whether anatomical and molecular changes in pp cells are correlated with tree resistance, we infected two norway spruce clones with the pathogenic fungus ceratocystis polonica (siem.) c. moreau. the fungus induced significantly different lesion lengths in the two clones, indicating that one clone was more resistant to the fungus ... | 2004 | 14996655 |
| pathogenicity of four blue-stain fungi associated with aggressive and nonaggressive bark beetles. | abstract the pathogenicity of two isolates of each of four bark beetle-associated blue-stain fungi was evaluated after mass inoculation of about 40-year-old norway spruce trees (picea abies). trees were inoculated with a different isolate of each fungus in 1995 and 1996 at a density of 400 inoculations per m(2) in a 1.2-m-wide band on the lower bole (about 270 inoculations per tree). trees were felled 15 weeks after inoculation. in 1995, ceratocystis polonica was the only fungus that had stained ... | 1998 | 18944997 |
| Induced terpene accumulation in Norway spruce inhibits bark beetle colonization in a dose-dependent manner. | Tree-killing bark beetles (Coleoptera, Scolytinae) are among the most economically and ecologically important forest pests in the northern hemisphere. Induction of terpenoid-based oleoresin has long been considered important in conifer defense against bark beetles, but it has been difficult to demonstrate a direct correlation between terpene levels and resistance to bark beetle colonization. | 2011 | 22028932 |
| functional identification and differential expression of 1-deoxy-d-xylulose 5-phosphate synthase in induced terpenoid resin formation of norway spruce (picea abies). | conifers produce terpenoid-based oleoresins as constitutive and inducible defenses against herbivores and pathogens. much information is available about the genes and enzymes of the late steps of oleoresin terpenoid biosynthesis in conifers, but almost nothing is known about the early steps which proceed via the methylerythritol phosphate (mep) pathway. here we report the cdna cloning and functional identification of three norway spruce (picea abies) genes encoding 1-deoxy-d-xylulose 5-phosphate ... | 2007 | 17687625 |
| methyl jasmonate treatment of mature norway spruce (picea abies) trees increases the accumulation of terpenoid resin components and protects against infection by ceratocystis polonica, a bark beetle-associated fungus. | when conifers such as picea abies karst. (norway spruce) are attacked by insects or pathogens, they often respond by producing increased quantities of terpenoid oleoresin. this response can be mimicked in young p. abies seedlings by treatment with methyl jasmonate (mj). in this study, we determined the effects of mj on terpenoids and other chemical defenses of mature p. abies, and investigated whether this treatment protected trees against attack by the blue-stain fungus ceratocystis polonica (s ... | 2006 | 16651247 |
| phenotypic and dna sequence data comparisons reveal three discrete species in the ceratocystis polonica species complex. | ceratocystis polonica and c. laricicola are two morphologically similar species that occur on conifers and reside in the ceratocystis coerulescens species complex. they, however, represent two ecologically distinct entities. c. polonica causes blue stain on norway spruce (picea abies) and other spruce species (picea spp.) in eurasia and is associated with the bark beetles ips typographus, i. typographus japonicus, i. amitinus and i. duplicatus. in contrast, c. laricicola lives in a symbiotic rel ... | 2005 | 16279408 |
| phloem parenchyma cells are involved in local and distant defense responses to fungal inoculation or bark-beetle attack in norway spruce (pinaceae). | the anatomical response of norway spruce bark polyphenolic parenchyma cells (pp cells) to inoculation with the phytopathogenic fungus ceratocystis polonica and attack by its bark-beetle vector ips typographus was examined. fungal inoculation on the periderm surface had no effect, while inoculation just below the periderm or halfway into the phloem (mid-phloem) generated detectable responses within 3 wk. the responses included increase in pp cell size and in periodic acid-schiff's staining of pp ... | 2000 | 10718992 |
| wound-induced traumatic resin duct development in stems of norway spruce (pinaceae): anatomy and cytochemical traits. | wounding of norway spruce by inoculation with sterile agar, or agar containing the pathogenic fungus ceratocystis polonica, induced traumatic resin duct formation in the stem. visible anatomical responses occurred in the cambium 6-9 d post-inoculation. near the inoculation site cellular proliferation, polyphenolic accumulation, and lignification were induced as a wound reaction to seal the damaged area. five centimetres from the inoculation site cells in the cambial zone swelled and divided to f ... | 2000 | 10718991 |
| host responses in norway spruce roots induced to the pathogen ceratocystis polonica are evaded or suppressed by the ectomycorrhizal fungus laccaria bicolor. | the outcome of a compatible mycorrhizal interaction is different from that in a compatible plant-pathogen interaction; however, it is not clear what mechanisms are used to evade or suppress the host defence. the aim of this work is to reveal differences between the interaction of norway spruce roots to the pathogen ceratocystis polonica and the ectomycorrhizal laccaria bicolor, examine if l. bicolor is able to evade inducing host defence responses typically induced by pathogens, and test if prio ... | 2013 | 22640005 |
| local and systemic changes in expression of resistance genes, nb-lrr genes and their putative micrornas in norway spruce after wounding and inoculation with the pathogen ceratocystis polonica. | nb-lrr resistance proteins are involved in recognizing pathogens and other exogenous stressors in plants. resistance proteins are the first step in induced defence responses and a better understanding of their regulation is important to understand the mechanisms of plant defence. much of the post-transcriptional regulation in plants is controlled by micrornas (mirna). we examined the expression of five norway spruce mirna that may regulate nb-lrr related transcripts in secondary phloem (bark) of ... | 2012 | 22776433 |
| localization of phenolics in phloem parenchyma cells of norway spruce (picea abies). | norway spruce (picea abies) bark contains specialized phloem parenchyma cells that swell and change their contents upon attack by the bark beetle ips typographus and its microbial associate, the blue stain fungus ceratocystis polonica. these cells exhibit bright autofluorescence after treatment with standard aldehyde fixatives, and so have been postulated to contain phenolic compounds. laser microdissection of spruce bark sections combined with cryogenic nmr spectroscopy demonstrated significant ... | 2012 | 23150460 |
| a common fungal associate of the spruce bark beetle metabolizes the stilbene defenses of norway spruce. | norway spruce (picea abies) forests suffer periodic fatal attacks by the bark beetle ips typographus and its fungal associate, ceratocystis polonica. norway spruce protects itself against fungal and bark beetle invasion by the production of terpenoid resins, but it is unclear whether resins or other defenses are effective against the fungus. we investigated stilbenes, a group of phenolic compounds found in norway spruce bark with a diaryl-ethene skeleton with known antifungal properties. during ... | 2013 | 23729780 |
| conifer stored resources and resistance to a fungus associated with the spruce bark beetle ips typographus. | bark beetles and associated fungi are among the greatest natural threats to conifers worldwide. conifers have potent defenses, but resistance to beetles and fungal pathogens may be reduced if tree stored resources are consumed by fungi rather than used for tree defense. here, we assessed the relationship between tree stored resources and resistance to ceratocystis polonica, a phytopathogenic fungus vectored by the spruce bark beetle ips typographus. we measured phloem and sapwood nitrogen, non-s ... | 2013 | 23967298 |
| flavan-3-ols in norway spruce: biosynthesis, accumulation, and function in response to attack by the bark beetle-associated fungus ceratocystis polonica. | proanthocyanidins (pas) are common polyphenolic polymers of plants found in foliage, fruit, bark, roots, rhizomes, and seed coats that consist of flavan-3-ol units such as 2,3-trans-(+)-catechin and 2,3-cis-(-)-epicatechin. although the biosynthesis of flavan-3-ols has been studied in angiosperms, little is known about their biosynthesis and ecological roles in gymnosperms. in this study, the genes encoding leucoanthocyanidin reductase, a branch point enzyme involved in the biosynthesis of 2,3-t ... | 2014 | 24550241 |
| using laser micro-dissection and qrt-pcr to analyze cell type-specific gene expression in norway spruce phloem. | the tangentially oriented polyphenolic parenchyma (pp) and radially organized ray parenchyma in the phloem are central in the defense of conifer stems against insects and pathogens. laser micro-dissection enables examination of cell-specific defense responses. to examine induced defense responses in norway spruce stems inoculated with the necrotrophic blue-stain fungus ceratocystis polonica, rna extracted from laser micro-dissected phloem parenchyma and vascular cambium was analyzed using real-t ... | 2014 | 24860697 |
| application of methyl jasmonate on picea abies (pinaceae) stems induces defense-related responses in phloem and xylem. | application of 100 mmol/l methyl jasmonate (mj) to the intact bark of 30-yr-old norway spruce induced anatomical reactions related to defense. within 30 d, a single mj treatment induced swelling of existing polyphenolic parenchyma cells (pp cells) and an increase in their phenolic contents and formation of additional pp cells and of traumatic resin ducts (tds) at the cambial zone. these changes occurred up to 7 cm away from the application zone. treatment enhanced resin flow and increased resist ... | 2002 | 21665658 |
| specialized phloem parenchyma cells in norway spruce (pinaceae) bark are an important site of defense reactions. | the bark anatomy of norway spruce clones that were resistant or susceptible to ceratocystis polonica, a bark-beetle-vectored fungal pathogen, was compared. the major difference concerned the axial parenchyma cells, called polyphenolic parenchyma (pp cells) because of their vacuolar deposits. the phenolic nature of the deposits was indicated by autofluorescence under blue light, and immunocytochemical studies demonstrating pp cells are enriched in phenylalanine ammonia lyase (ec 4.3.1.5), a key e ... | 1998 | 21684942 |
| the influence of ceratocystis polonica inoculation and methyl jasmonate application on terpene chemistry of norway spruce, picea abies. | constitutive and inducible terpene production is involved in conifer resistance against bark beetles and their associated fungi. in this study 72 norway spruce (picea abies) were randomly assigned to methyl jasmonate (mj) application, inoculation with the bluestain fungus ceratocystis polonica, or no-treatment control. we investigated terpene levels in the stem bark of the trees before treatment, 30 days and one year after treatment using gc-ms and two-dimensional gc (2d-gc) with a chiral column ... | 2010 | 20557909 |
| fungi vectored by the bark beetle ips typographus following hibernation under the bark of standing trees and in the forest litter. | the bark beetle ips typographus has different hibernation environments, under the bark of standing trees or in the forest litter, which is likely to affect the beetle-associated fungal flora. we isolated fungi from beetles, standing i. typographus-attacked trees, and forest litter below the attacked trees. fungal identification was done using cultural and molecular methods. the results of the two methods in detecting fungal species were compared. fungal communities associated with i. typographus ... | 2009 | 19444498 |
| methyl jasmonate and oxalic acid treatment of norway spruce: anatomically based defense responses and increased resistance against fungal infection. | to study the effect of chemical pretreatment on conifer resistance, 13-year-old norway spruce (picea abies (l.) karst.) trees were treated with methyl jasmonate (mj) or oxalic acid (oxa) on the outer bark and inoculated with the pathogenic blue-stain fungus ceratocystis polonica (siem.) c. moreau 4 weeks later. both chemicals significantly reduced symptoms of fungal infection, but mj was more effective than oxa (51 versus 18% reduction in length of necrotic lesions in the phloem relative to untr ... | 2008 | 17938111 |