Publications by R.N. Sturrock

Effects of biotic disturbances on forest carbon cycling in the United States and Canada.

Fri, 04 Nov 2011

Forest insects and pathogens are major disturbance agents that have affected millions of hectares in North America in recent decades, implying significant impacts to the carbon (C) cycle. Here, we review and synthesize published studies of the effects of biotic disturbances on forest C cycling in the United States and Canada. Primary productivity in stands was reduced, sometimes considerably, immediately following insect or pathogen attack. After repeated growth reductions caused by some insects or pathogens or a single infestation by some bark beetle species, tree mortality occurred, altering productivity and decomposition. In the years following disturbance, primary productivity in some cases increased rapidly as a result of enhanced growth by surviving vegetation, and in other cases increased slowly because of lower forest regrowth. In the decades following tree mortality, decomposition increased as a result of the large amount of dead organic matter. Net ecosystem productivity decreased immediately following attack, with some studies reporting a switch to a C source to the atmosphere, and increased afterward as the forest regrew and dead organic matter decomposed. Large variability in C cycle responses arose from several factors, including type of insect or pathogen, time since disturbance, number of trees affected, and capacity of remaining vegetation to increase growth rates following outbreak. We identified significant knowledge gaps, including limited understanding of carbon cycle impacts among different biotic disturbance types (particularly pathogens), their impacts at landscape and regional scales, and limited capacity to predict disturbance events and their consequences for carbon cycling. We conclude that biotic disturbances can have major impacts on forest C stocks and fluxes and can be large enough to affect regional C cycling. However, additional research is needed to reduce the uncertainties associated with quantifying biotic disturbance effects on the North American C budget.

Laminated Root Disease - Stand Establishment Decision Aid

Thu, 17 Nov 2011

Laminated (or Phellinus) root disease (Phellinus sulphurascens Pilát, syn. = P. weirii) is a major, naturally occurring disturbance agent in interior forests and poses a significant threat to its most economically important host, Douglas-fir. The disease spreads below ground at root contacts. In the southern interior of British Columbia, P. sulphurascens often occurs together with Armillaria root disease (Armillaria ostoyae) and (or) Douglas-fir bark beetle (Dendroctonus pseudotsugae). Stand volume in infested areas can be significantly reduced through growth loss and decay, mortality, and windthrow. Post-harvest retention of infected stumps in the soil increases inoculum potential on affected sites, which poses a risk of infection to regenerating trees. Mitigation of disease impacts can best be achieved by recognition of the disease and incidence assessment prior to harvest, and by modification of harvesting and silviculture practices that will minimize exposure of trees to inoculum. The Stand Establishment Decision Aid (SEDA) format has been used to extend information on various vegetation and forest health concerns in British Columbia. This decision aid summarizes information about laminated root disease occurrence and management in the Southern Interior Forest Region. The first sections provide general information, hazard ratings, and biological and silvicultural considerations for Phellinus root disease. The article then outlines growth and yield implications, other effects and associations of the disease, and various techniques to manage the disease. It also includes a list of references and resources to provide readers with more detailed information. Reference material that is not available online can be ordered through libraries or the Queen’s Printer at http://www.qp.gov.bc.ca.

Conifer Chitinases

Thu, 09 Jun 2011

Over the last two decades scientists have focused much attention on the physiological, molecular and functional biology of plant chitinases and there is considerable evidence suggest that chitinases play important roles in plant defense systems. Chitinases have also been shown to play a role in plant growth and development. Several review articles exist for chitinases of angiosperms but there is no such review for conifer chitinases, despite the economic and ecological significance of coniferous species in the world’s forests. Conifer chitinases consist of at least several classes of enzymes that are represented by small gene families. Class II (acidic) and class IV (basic) chitinases, expressed differentially over time and space, have been shown to be the major defense players in many conifer pathosystems. Class I and III chitinases are also reported in some conifers. This review discusses the current body of knowledge regarding conifer chitinases, including the molecular structure of chitinase genes and their regulation and function in conifer plants. Future potential uses for conifer chitinases as biopesticides and agents of biofuel production are also discussed.

Climate change and forest diseases

Fri, 21 Jan 2011

As climate changes, the effects of forest diseases on forest ecosystems will change. We review knowledge of relationships between climate variables and several forest diseases, as well as current evidence of how climate, host and pathogen interactions are responding or might respond to climate change. Many forests can be managed to both adapt to climate change and minimize the undesirable effects of expected increases in tree mortality. We discuss four types of forest and disease management tactics – monitoring, forecasting, planning and mitigation – and provide case studies of yellow-cedar decline and sudden aspen decline to illustrate how forest diseases might be managed in the face of climate change. The uncertainties inherent to climate change effects can be diminished by conducting research, assessing risks, and linking results to forest policy, planning and decision making.

The superfamily of thaumatin-like proteins: its origin, evolution, and expression towards biological function

Tue, 13 Apr 2010

Thaumatin-like proteins (TLPs) are the products of a large, highly complex gene family involved in host defence and a wide range of developmental processes in fungi, plants, and animals. Despite their dramatic diversification in organisms, TLPs appear to have originated in early eukaryotes and share a well-defined TLP domain. Nonetheless, determination of the roles of individual members of the TLP superfamily remains largely undone. This review summarizes recent advances made in elucidating the varied TLP activities related to host resistance to pathogens and other physiological processes. Also discussed is the current state of knowledge on the origins and types of TLPs, regulation of gene expression, and potential biotechnological applications for TLPs.

Identification, Characterization, and Expression Analyses of Class II and IV Chitinase Genes from Douglas-Fir Seedlings Infected by Phellinus sulphurascens

Tue, 09 Mar 2010

Laminated root rot (LRR) disease, caused by the fungus Phellinus sulphurascens, is a major threat to coastal Douglas-fir (DF) (Pseudotsuga menziesii) forests in western North America. Understanding host–pathogen interactions of this pathosystem is essential to manage this important conifer root disease. Our research objectives were to identify DF pathogenesis-related (PR) genes and analyze their expression patterns over the course of infection. We constructed a cDNA library of Phellinus sulphurascens-infected DF seedling roots and sequenced a total of 3,600 random cDNA clones from this library. One of the largest groups of identified genes (203 cDNA clones) matched with chitinase genes reported in other plant species. We identified at least three class II and six class IV chitinase genes from DF seedlings. Quantitative reverse-transcriptase polymerase chain reaction analyses showed significant differential expression patterns locally in root tissues and systemically in needle tissues after fungal invasion. Nonetheless, there was a common trend in gene expression patterns for most of the chitinase genes: an upregulation within 12 h of pathogen inoculation followed by down-regulation within 2 to 3 days postinoculation (dpi), and then further upregulation within 5 to 7 dpi. Western immunoblot data showed differential accumulation of class IV chitinases in Phellinus sulphurascens-infected DF seedlings. Further detailed functional analyses will help us to understand the specific role of DF chitinases in defense against Phellinus sulphurascens infection.

Ultrastructural studies of Phellinus sulphurascens infection of Douglas-fir roots and immunolocalization of host pathogenesis-related proteins

Tue, 10 Mar 2009

Interactions between roots of Douglas-fir (DF; Pseudotsuga menziesii) seedlings and the laminated root rot fungus Phellinus sulphurascens were investigated using scanning and transmission electron microscopy and immunogold labelling techniques. Scanning electron micrographs revealed that P. sulphurascens hyphae colonize root surfaces and initiate the penetration of root epidermal tissues by developing appressoria within 2 d postinoculation (dpi). During early colonization, intra- and intercellular fungal hyphae were detected. They efficiently disintegrate cellular components of the host including cell walls and membranes. P. sulphurascens hyphae penetrate host cell walls by forming narrow hyphal tips and a variety of haustoria-like structures which may play important roles in pathogenic interactions. Ovomucoid-WGA (wheat germ agglutinin) conjugated gold particles (10 nm) confirmed the occurrence and location of P. sulphurascens hyphae, while four specific host pathogenesis-related (PR) protein antibodies conjugated with protein A-gold complex (20 nm) showed the localization and abundance of these PR proteins in infected root tissues. A thaumatin-like protein and an endochitinase-like protein were both strongly evident and localized in host cell membranes. A DF-PR10 protein was localized in the cell walls and cytoplasm of host cells while an antimicrobial peptide occurred in host cell walls. A close association of some PR proteins with P. sulphurascens hyphae suggests their potential antifungal activities in DF roots.

Histochemical and proteomics approaches to study host-pathogen interactions of the douglas-fir-Phellinus sulphurascens pathosystem

Mon, 07 Nov 2011

Distinguishing homokaryons and heterokaryons in Phellinus sulphurascens using pairing tests and ITS polymorphisms

Wed, 08 Apr 2009

Phellinus sulphurascens Pilát causes laminated root rot of coniferous species in both western North America (WNA) and Asia. Accurate somatic incompatibility tests for mapping population structures have been difficult to conduct for P. sulphurascens because no single, unambiguous criterion has allowed differentiation of homokaryotic and heterokaryotic isolates. In a population study of P. sulphurascens in WNA, two types of ITS sequences were found in the single spore and vegetative isolates. All single spore isolates (SSIs) had either ITS type-1 or type-2 whereas some vegetative isolates had both ITS types. The segregation pattern for inheritance of ITS, which we observed in SSIs from eight basidiocarps, suggested that each ITS type occurred in a different nucleus and that each basidiospore inherited only one ITS type. In four SSIs from Russia and eight heterokaryotic isolates from Japan, nine different ITS types, referred to as type-3 to -11, were detected. A variety of pairing tests conducted between known Asian and WNA homokaryon and heterokaryon isolates did not always give consistent results with respect to fungal mat morphologies and formation of demarcation lines. However, the ITS types that occurred after pairing tests did follow consistent patterns. Thus, using ITS polymorphisms and pairing tests between Asian tester isolates and 49 vegetative isolates from WNA, we were able to accurately distinguish between homokaryotic and heterokaryotic isolates.

A proteomics approach to identify proteins differentially expressed in Douglas-fir seedlings infected by Phellinus sulphurascens

Wed, 12 Nov 2008

We carried out a comparative proteomic study to explore the molecular mechanisms that underlie the defense response of Douglas-fir (DF, Pseudotsuga menziesii) to laminated root rot, a disease caused by Phellinus sulphurascens. 2-DE was conducted on proteins extracted from roots of laboratory-grown, young DF seedlings inoculated with P. sulphurascens. A total of 1303 proteins was detected in 7 dpi infected and uninfected root samples. Among these 1303 proteins, 277 showed differential expression that was statistically significant (p < 0.05). Of these 277 proteins, 74 upregulated and 85 downregulated proteins showed at least a two-fold change from controls. Forty seven upregulated and 23 downregulated proteins were selected to be excised and analyzed using LC–MS/MS followed by peptide matching. Our results indicate that the major proteins differentially expressed in P. sulphurascens-infected DF seedlings include those in the following functional groups: disease/defense (27%), metabolism (16%), transcription factors (11%), signal transduction (10%), secondary metabolism (7%) and energy (4%). A number of additional proteins involved in cell structure (3%) and protein synthesis (3%) were also identified. By providing an initial database of candidate pathogenesis-related proteins for the DF–Phellinus sulphurascens pathosystem the results of this study will enable future detailed investigation of gene expression and function.

Host-pathogen interactions in Douglas-fir seedlings infected by Phellinus sulphurascens

Wed, 17 Oct 2007

Several aspects of the host-pathogen interaction between Douglas-fir (Pseudotsuga menziesii) and the fungal pathogen Phellinus sulphurascens were investigated in an in vitro inoculation system using young seedlings and fungal mycelia. Light microscopy confirmed that P. sulphurascens mycelia can successfully penetrate host epidermal cells within 3 days postinoculation (dpi). Extensive fungal colonization and cortical cell decay occurred within 14 dpi. Western immunoblot studies showed significant upregulation (five to sixfold) of four specific pathogenesis-related (PR) proteins in infected roots. These proteins were a Douglas-fir thaumatin- like protein (PmTLP), an endochitinase protein (ECP), a Douglas-fir PR10 (DF-PR10) protein (PsemI), and a 10.6-kDa antimicrobial peptide (PmAMP1). The highest accumulation of PmTLP and PmAMP1 occurred at 12 dpi, whereas accumulations of the ECP and DF-PR10 proteins peaked at 7 dpi. For both inoculated and control Douglas-fir seedlings, only one of the four PR proteins, PmAMP1, was clearly detectable in needles. Immunolocalization experiments using fluorescein isothiocyanate-conjugated secondary antibodies confirmed accumulation of all four PR proteins mainly in and around cell walls of root cortical tissues. Overall, the highest immunofluorescence was observed in infected roots at 12 dpi, whereas labeling in control roots was negligible at all sample times. The ECP produced the highest fluorescence; the DF-PR10 the lowest. Upregulation and localization of these PR proteins in cortical tissues of inoculated roots suggest that they play a defensive role in response to infection by P. sulphurascens. This in vitro inoculation system will facilitate further proteomic and genomic studies of this important pathosystem.

British Columbia's coastal forests: laminated root rot forest health stand establishment decision aid

Wed, 22 Aug 2007

Laminated root rot stand establishment decision aid

Fri, 09 Feb 2007

Laminated root rot (Phellinus weirii) is the most prominent root disease of Douglas-fir in coastal coniferous forests and is endemic throughout its host’s range in British Columbia. The disease spreads primarily via root contact and can attack and gradually kill trees throughout their life cycle. It can lower stand volume by 40–70% on infected sites and acts as a stand-altering disturbance agent. The retention of infected stumps and residual trees (via partial cutting) can perpetuate the incidence of laminated root rot in a regenerating stand by leaving material on site to act as reservoirs of disease. To mitigate disease impact, a good understanding of the distribution and biology of P. weirii is necessary. The cedar form of P. weirii, which is responsible for a butt rot in western redcedar, is not covered in this extension note. The Stand Establishment Decision Aid (seda) format has been used to extend information on various vegetation and forest health concerns in British Columbia. This decision aid summarizes information that relates current management regimes to the spread and effects of laminated root rot.

Diversity and virulence of Phellinus weirii in British Columbia: results from two studies

Mon, 07 Nov 2011

Characterization of four terpene synthase cDNAs from a methyl jasmonate-induced Douglas-fir, Pseudotsuga menziesii

Fri, 09 Feb 2007

Numerous terpenoid compounds are present in copious amounts in the oleoresin produced by conifers, especially following exposure to insect or fungal pests. CDNA clones for many terpene synthases responsible for the biosynthesis of these defense compounds have been recovered from several conifer species. Here, the use of three terpene synthase sequences as heterologous probes for the discovery of related terpene synthase genes in Douglas-fir, Pseudotsuga menziesii (Mirbel) Franco (Pinaceae), is reported. Four full-length terpene synthase cDNAs were recovered from a methyl jasmonate-induced Douglas-fir bark and shoot cDNA library. These clones encode two multi-product monoterpene synthases [a (-)-?-pinene/(-)-camphene synthase and a terpinolene synthase] and two single-product sesquiterpene synthases [an (E)-?-farnesene synthase and a (E)-?-bisabolene synthase].

Differentiating the two closely related species, Phellinus weirii and P. sulphurascens

Fri, 09 Feb 2007

Phellinus weirii s.l., an aggressive root rot pathogen, causes extensive wood losses and lowers the productivity of western red cedar (WRC, Thuja plicata), Douglas fir (Pseudotsuga menziesii) and other conifers. This fungus has been recognized as a cedar form (P. weirii s.s.) and a non-cedar form (P. sulphurascens). Differentiating the two species is difficult because their fruiting bodies and cultural morphologies are very similar. However, differences in growth rate and colony morphology were observed when they were grown on malt extract agar with WRC feeder strips. In addition, different restriction fragment length polymorphism patterns were obtained using (i) the internal transcribed spacer (ITS) region cut with the restriction enzyme RsaI, and (ii) the partial large subunit ribosomal DNA region cut with AgeI and NciI. Furthermore, a new specific primer set was designed from the ITS region of P. weirii s.s. and was used to differentiate it from P. sulphurascens and other decay fungi that are frequently found in coniferous trees. These species-specific primers will facilitate the detection of P. weirii in standing trees well before visible signs of infection are apparent.

Changes in anatomy and terpene chemistry in roots of Douglas-fir seedlings following treatment with methyl jasmonate

Thu, 04 Aug 2005

Replicated trials were conducted on two full-sibling families of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings. In response to the application of a 0.01% solution of methyl jasmonate (MeJA) to the soil of potted seedlings, numerous anatomical and chemical changes were observed in the roots, stem and foliage. These changes were, for the most part, similar for both sib groups. Methyl jasmonate induced traumatic resin duct formation in roots and stems. Chemical differences between MeJA-treated and control seedlings were mainly limited to the roots and stem, though some changes also occurred in the foliage. A total of 35 terpenoids were observed in the P. menziesii seedlings. In response to MeJA treatment, several of the 22 detected monoterpenoids (linalool, bornyl acetate, camphene, myrcene, alpha- and beta-pinene, tricyclene and beta-phellandrene) increased significantly in roots and stems, whereas (E)-beta-ocimene decreased significantly in the foliage. Four of the five detected sesquiterpenoids (alpha-humulene, germacrene D, longifolene and (E)-caryophyllene) increased significantly following MeJA application, mainly in the root and stem. Four of the eight detected diterpenoids (abietate, levopimarate, palustrate and sandaracopimarate) increased in response to MeJA treatment, but only in root and stem tissue. This study provides the first description of the effects of MeJA applied to roots through the soil on the anatomy and terpene chemistry of a gymnosperm. This comprehensive inventory of terpenoids in P. menziesii, with and without MeJA treatment, may facilitate identification of terpenoid-related resistance traits. Potential practical applications of MeJA treatment of conifer roots as a pest management strategy are discussed.

Gene Cloning and Tissue Expression Analysis of a PR-5 Thaumatin-Like Protein in Phellinus weirii-Infected Douglas-Fir

Thu, 02 Dec 2004

In western North America, Douglas-fir (Pseudotsuga menziesii) is the most economically important conifer species susceptible to laminated root rot caused by Phellinus weirii. While attempting to internally sequence an endochitinase found to be up-regulated in P. weirii-infected Douglas-fir roots, we obtained overlapping peptide fragments showing 28% similarity with a PR-5 thaumatin-like protein (TLP) designated PmTLP (Pm for Pseudotsuga menziesii). A rabbit polyclonal antibody was reared against a synthetic peptide composed of a 29-amino-acid-long, conserved, internal sequence of PmTLP and purified by immunoaffinity. Western immunoblot analysis of infected roots of 24-year-old coastal Douglas-fir showed significantly higher amounts of PmTLP (P < 0.01) closest to the point of P. weirii inoculation and infection than in uninfected regions of the same root. The antibody was also used to screen for PmTLP in roots of 25-year-old interior Douglas-firs naturally infected with a related pathogen, Armillaria ostoyae, and results showed significantly higher levels of PmTLP in bark tissues adjacent to infection (P < 0.05) than in uninfected tissue. Using polymerase chain reaction (PCR)-based cloning, the cDNA of PmTLP was shown to have a 702-bp open reading frame with a signal peptide cleavage site at 155 bp corresponding to a 29-amino-acid-long residue prior to the start of the N-terminal. Based on the deduced amino acid sequence, the molecular mass of the putative PmTLP was calculated to be 21.0 kDa with an isoelectric point of 3.71. Alignment analysis of PmTLP cDNA with a representative genomic DNA PCR sequence showed presence of one intron of variable size, within the coding region. The induction of PmTLP at the site of root infection and its presence in needle tissue suggests a general role for this protein in adaptation to stress and may be part of an integrated defense response initiated by the host to impede further pathogen spread. Additional keywords: ectotrophic mycelium, defense-related protein, mass spectrometry analysis.

Detection and assessment of trees with Phellinus weirii (laminated root rot) using high resolution multi-spectral imagery

Thu, 18 Mar 2004

The forests of western North America are affected by root diseases caused by several endemic fungi. These have both important economical and ecological impacts. Phellinus weirii (laminated root rot) is particularly important in coastal Douglas-fir forests. Forest managers would like know the location of pockets of Phellinus weirii infected trees for the purpose of salvage, remedial activities and inventory. Airborne multispectral imagers, coupled with automated detection of damaged trees have potential to provide a cost-effective survey method.

Two sets of casi airborne multispectral imagery were acquired at 60 cm resolution over the same Douglas-fir dominated site in coastal British Columbia, Canada. They were acquired in successive years and radiometric corrections for the effects of illumination and view angle applied. Trees of varying levels of root rot symptoms were assessed in the field and manually delineated on the imagery. Spectral properties of these trees were related to levels of damage symptoms. There was considerable overlap of the spectral signatures of the different damage levels, especially healthy through moderate. The range of reflectances for healthy trees was large. The near-infrared and red bands and band ratio involving those two bands proved most related to root rot damage. A blue band was also useful, as were ratios of the near-infrared or red bands to the blue band. Classification of these trees using the best combination of four spectral bands indicated average class accuracies in the order of 55% to 60% for healthy, light-healthy, light, moderate, severe, 100% needle loss, snag and shadowed snag classes. There was important confusion among the moderate through to healthy class. However, these classes are a finer categorization than is necessary for most applications. Accuracy for broader classes was much better (e.g. average class accuracies were 82% if a tolerance of +/- one class is permitted, ranging from 50 to 100% for individual classes). An automated tree isolation method was applied to the data. This automated tree isolation was good for the 1995 data but suffered from splitting of large trees into several segments on the 1996 data. All but one of the ground truth trees had associated isolated tree crowns. Classification of the isolations corresponding well to ground truth trees was similar to accuracies for the manually delineated trees, but poorer if ground truth trees without a good matched isolation are considered an error (42% and in the order of 60% with a +/- one class tolerance). The overall distribution of root rot damaged trees as indicated by the automated tree isolation and classification was spot checked throughout the site. There was a generally good correspondence, with concentrations of moderate and severe damage trees being associated with areas of root disease. Concentrations of predominantly light damage trees were not a reliable indication of root disease, and forest regions where the main symptoms of root disease are light will be difficult to survey. Some damage zones occurred that seemed to be related to poor health but not specifically related to root disease. As well, isolated trees of similar characteristics as laminated root rot infected trees do appear on the imagery in scattered locations unrelated to root disease activity. It is felt that these false alarms can be largely mitigated by identifying the characteristic pattern of root damaged trees (i.e. stressed trees around a centre, the centre often being a hole or gap in the canopy). High resolution multispectral imagery combined with automated procedures seem viable for detecting laminated root rot centres when severe symptoms are present.

Demonstration of root rot tracter

Fri, 27 May 2011

Endochitinase activity in the apoplastic fluid of Phellinus weirii-infected Douglas-fir and its association with over wintering and antifreeze activity

Tue, 30 Sep 2003

Extracellular proteins were extracted from Phellinus weirii infected Douglas-fir (Pseudotsuga menziesii var. menziesii) roots and needles to examine endochitinase activity. Chitinases have been associated with the plant's defence response against fungal attack because they hydrolyse chitin, a structural component of fungal cell walls. Protein separation using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) followed by Western immunoblot analysis using a polyclonal antibody specific to an endochitinase-like protein (ECP) resulted in the detection of up to three polypeptides between 27 and 30 kDa in size. Two-dimensional gel electrophoresis (2-D PAGE) followed by Western immunoblot analysis revealed that the apoplastic fluid contained multiple ECP isoforms with isoelectric points (pIs) ranging from 5.3 to 5.8 and molecular masses of 27-30 kDa. Chitinase activity in needle and root tissues was measured spectrophotometrically using a colorimetric assay. A gel overlay technique using glycol chitin as a substrate for endochitinase was applied to confirm that the ECP antibody detected an enzymatically active protein. The apoplastic fluid collected from P. weirii-infected winter Douglas-fir needles showed anti-freeze activity and seasonal analysis of needle tissue showed some evidence of ECP accumulation in winter months. ECP was distributed systemically throughout the tree. Increased levels of endochitinase activity in the region of P. weirii infection supports a physiological role for ECP in the plant defence response.

The antigen reactive to an anti-white pine blister rust fungal monoclonal antibody (Mab 7) is a homologue of 70-k-Da heat shock proteins (a BiP protein)

Fri, 28 Dec 2001

The production and characterization of monoclonal antibodies (Mab) to the white pine blister rust (WPBR) fungus (Cronartium ribicola) were described by Ekramoddoullah and Taylor (1996). One of the monoclonal antibodies, Mab 7, detected a major mycelial antigen on blister rust. This monoclonal antibody did not cross-react with proteins from the white pine host or with proteins from other fungal species that were known to infect western white pine. As part of our ongoing work on the potential use of Mab 7 as a plantibody for engineering WPBR-resistant white pine, we report here on the cloning and characterization of cDNA encoding the antigen reactive to Mab 7. Five rounds of immunoscreening of a Uni-ZAP expression cDNA library from poly (a) + mRNA of C. ribicola mycelia with Mab 7 led to the identification of three positive clones. One of them was completely sequenced. Sequence analysis indicated an open reading frame of 2010 bases encoding a protein (designated as Cro r II) of 669 amino acid residues with a molecular mass of 72.9 kDa and a predicted isoelectric point of 5.0. Two-dimensional silver-stained gels and 2-D Western analyses detected multiple spots with the same molecular mass and slightly different pI around pH 5.0, suggesting isoforms of Cro r II. A BLAST search of the NCBI database with the deduced Cro r II protein sequence indicated homology with a group of 70-kDa heat shock proteins. Southern blot hybridizations indicated that the C. ribicola genome contained at least one copy of the Cro r II gene. Western immunoblot analyses revealed that the Cro r II protein was present in mycelial culture, in the infected white pine tissues, in the alternate infected Ribes stage, and in the five different spore stages, suggesting a constitutive role for Cro r II in the fungus.

Detection and seasonal expression pattern of a pathogenesis-related protein (PR-10) in Douglas-fir (Pseudotsuga menziesii) tissues.

Thu, 19 Oct 2000

Previously, a PR-10 protein Pin m III was described in western white pine. In this study, primers based on cDNA of Pin m III were utilized to obtain the genomic sequence of a Pin m III homologue - Pse m I - in Douglas-fir. A comparative analysis of a deduced amino acid sequence of Pin m III and Pse m I genes indicated about 80% similarity between the two protein sequences, and a consensus 20 amino-acid sequence located around the p-loop sequence was used to synthesize a peptide of 20 amino acids. An antibody to this synthetic peptide was able to detect the Pse m I protein in Douglas-fir. The anti-Pse m I antibody was used in a western immunoblot to monitor seasonal variation of the Pse m I in Douglas-fir needles and its level was shown to increase with overwintering of Douglas-fir seedlings. However, unlike the Pin m III, there is no indication that the Pse m I is associated with frost hardiness. Analysis of infected Douglas-fir roots showed a possible trend to up-regulation of Pse m I by pathogens such as the laminated root rot fungus, Phellinus weirii. The expression of Pse m I protein in Douglas-fir seedlings is very low compared to the expression of Pin m III protein in western white pine seedlings. In addition, a light-harvesting complex I protein, PSI-F was identified in Douglas-fir by N-terminal amino acid sequencing.

Lutte contre les maladies racinaires par dessouchage et abattage par poussée

Wed, 27 Sep 2000

Technology Transfer Notes are a new series of publications focusing on forestry research applications. Technology Transfer Notes offer new techniques, methods, tools and procedures, and deliver research results of interest to the operational forest manager.

Management of root diseases by stumping and push-falling

Sat, 26 Aug 2000

Detection of a chitinase-like protein in the roots of Douglas-fir trees infected with Armillaria ostoyae and Phellinus weirii

Sat, 26 Aug 2000

Protein was extracted from root bark of 11- and 25-year-old interior Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees that were naturally infected with Armillaria ostoyae (Romagnesi) Herink. The proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Root bark tissue adjacent to infected areas had a significantly higher protein concentration than healthy tissue (P<0.05), whereas the protein concentration of infected tissue was consistently lower (P<0.05) than that of healthy tissue. The SDS-PAGE profiles of healthy, infected, and adjacent-to-infected root bark tissues revealed significant differences in concentrations of a 29.3-kDa protein. The N-terminal amino acid sequence of the 29.3-kDa protein displayed significant homology (P=0.013) to a basic endochitinase. Use of a polyclonal antibody raised against the 29.3-kDa putative endochitinase-like protein (ECP) indicated differences in the quantities of ECP in healthy roots compared with roots infected with A. ostoyae in 11- and 25-year-old interior Douglas-fir trees. The antibody was also used to screen for the presence of the 29.3-kDa protein in roots of 24-year-old coastal Douglas-fir (Pseudotsuga menziesii var. menziesii) trees that were artificially inoculated with and colonized by Phellinus weirii (Murr.) Gilbn. The amount of ECP was elevated in root bark of coastal Douglas-fir in response to P. weirii infection, although in lower quantities relative to those found in the A. ostoyae-interior Douglas-fir pathosystem. The sequence homology of the ECP with a basic chitinase, together with its increased synthesis in response to two fungal pathogens, indicate a possible role for this protein in the defense of Douglas-fir against fungal pathogens.

Initial work on a mathematical model for the tree-to-tree spread of forest root disease with a demonstration of part of its implementation. (Abstract)

Tue, 27 Sep 2011

Computer demonstration of preliminary work on mathematical description of root disease spread through root contact and fungus transfer

Tue, 27 Sep 2011

Preliminary assessment of Phellinus weirii-infected (laminated root rot) trees with high resolution CASI imagery

Sat, 26 Aug 2000

Root diseases caused by several endemic fungi are economically and ecologically important disturbance agents in the forests of western North America. Laminated root rot (Phellinus weirii) has particularly important impact in coastal Douglas-fir stands. Forest managers would like an economical survey procedure for detecting pockets of Phellinus weirii infected trees for the purpose of salvage, remedial activities and inventory. Aerial survey with multispectral imagers such as casi, coupled with automated detection of damaged trees may provide a cost-effective survey method. Casi imagery in eight spectral bands has been corrected to an orthoimage and radiometric corrections for the effects of illumination and view angle applied. Trees of varying levels of root rot symptoms were assessed in the field and related to delineated trees on the imagery. Visual symptoms on the ground ranged from subtle crown shape and growth rate changes, through gradual needle loss, to mortality. Chlorosis occurred on some trees. Preliminary analysis, including classification and regression analyses of symptom classes or levels, indicates that light crown symptoms will be difficult to consistently detect. However, moderate and severe damage including needle loss (e.g., > 25%) does appear to be detectable. Isolated trees of similar characteristics as root rot infected trees do appear on the imagery in scattered locations unrelated to root rot activity. It is anticipated that these false alarms can be largely mitigated by identifying the characteristic pattern of root rot damaged trees (i.e., stressed trees around a centre, the centre often being a hole or gap in the canopy).

A new technique for inoculation of conifer seedling roots with the laminated root rot pathogen, Phellinus weirii

Sat, 26 Aug 2000

The efficacy of a novel inoculation technique for infecting conifer seedling roots with Phellinus weirii was demonstrated. Inoculum units were prepared from P. weirii-colonized stem segments of red alder (Alnus rubra) and branch segments of Douglas-fir (Pseudotsuga menziesii). In one experiment, potted and outplanted seedlings of nine coniferous species of known susceptibility of P. weirii (Douglas-fir, grand fir, lodgepole pine, noble fir, Sitka spruce, western hemlock, western redcedar, western white pine, and yellow cedar) were inoculated using the novel inoculum units. For all nine species combined, transfer of ectotrophic P. weirii was greater for potted seedlings than for outplanted seedlings (93% vs. 48%). However, rates of endotrophic P. weirii infection were similar for potted and outplanted seedlings (81% and 77% respectively). Results of this experiment parallel reported species susceptibility to P. weirii. In a second experiment, rooted cuttings of English yew and Pacific yew, coniferous species of unknown susceptibility to P. weirii, were tested. Transfer of the fungus to rooted cuttings was good for Pacific yew (77%) and poor for English yew (29%). Mortality of rooted cuttings of yew showed a similar trend: 49% of Pacific yews with P. weirii successfully transferred to roots were killed by the fungus vs. no mortality in the English yews. This is the first study to document the relative susceptibility of Pacific yew and English yew to P. weirii. Use of the inoculation technique for older trees and other root disease fungi is discussed.

Proceedings of the forty-fifth western international forest disease work conference

Sat, 26 Aug 2000

Effects of laminated root rot (Phellinus weirii) on Douglas-fir foliar chemistry

Sat, 26 Aug 2000

To determine the effects of laminated root rot (Phellinus weirii) on Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) foliar chemistry, chlorophyll a and b, N, P, K, Ca, Mg, Mn, Fe, and foliage moisture were measured in new and old foliage from 20- to 80-year-old coastal Douglas-fir. Measurements were made in June and September of 1993 and June of 1994. Chlorophyll a and b, Ca, Fe, Mg, and Mn were higher in old foliage in both June and September, while moisture, N, and K were higher in the new foliage. The relationship of P to foliage age changed with time. Reductions in foliage moisture, chlorophyll a, and N were consistently associated with P. weirii infection in all plots, but the normal high variability in foliage chemistry made demonstration of statistical significance difficult. Within-tree variability in foliar chemistry was much higher in June than in September, especially in the new foliage.

Laminated root rot in western North America

Sat, 26 Aug 2000

Demonstration of a novel fungus inoculation technique to screen coastal Douglas-fir for genetic resistance to laminated root rot

Tue, 01 Jun 2010

Commercial thinning in coastal forest stands infested with laminated root rot: preliminary guidelines

Sat, 26 Aug 2000

Susceptibility of western conifers to laminated root rot

Sat, 26 Aug 2000

A trial of push-falling to reduce Phellinus weirii infection of Coastal Douglas-fir

Sat, 26 Aug 2000

Laminated root rot of Douglas-fir

Sat, 26 Aug 2000

Forest Pest Leaflets are a series of about eighty publications dealing with insects, tree diseases, and other problems affecting the growth, survival, and general health of forests. Each leaflet explains the distribution of these pest, the damage they cause, how to identify them, and the control options that may be available.

Susceptibility of western conifers to laminated root rot (Phellinus weirii) in Oregon and British Columbia field tests

Sat, 26 Aug 2000

Several species of conifers were outplanted around infected stumps in Oregon and British Columbia to measure their susceptibility to laminated root rot caused by Phellinus weirii. Grand fir (Abies grandis) experienced nearly 30% mortality caused by P. weirii. Douglas-fir (Pseudotsuga menziesii) mortality exceeded 20%. Noble fir (A. procera), Sitka spruce (Picea sitchensis), giant sequoia (Sequoiadendron giganteum), western hemlock (Tsuga heterophylla), and ponderosa pine (Pinus ponderosa) mortality averaged less than 10%. Western white pine (P. monticola) and lodgepole pine (P. contorta) mortality was less than 1%. Phellinus weirii did not cause mortality of western redcedar (Thuja plicata) or redwood (Sequoia sempervirens). Apparent susceptibility, based on mortality over 17-20 growing seasons, was similar to that recorded in past field observations.

Populations of adult fungus gnats and shore flies in British Columbia container nurseries as related to nursery environment, and incidence of fungi on the insects

Sat, 26 Aug 2000

Diseases and insects in British Columbia forest seedling nurseries

Sat, 26 Aug 2000

Grey mould control on container-grown Douglas-fir seedlings: Timing of fungicide application related to greenhouse environment

Sat, 26 Aug 2000

Grey mould control on container-grown Douglas-fir seedlings: Timing of fungicide application related to greenhouse environment

Sat, 26 Aug 2000

"Treetalk" Newsletter

Sat, 26 Aug 2000

Styroblock sanitization: results of laboratory assays from trials at several British Columbia forest nurseries

Sat, 26 Aug 2000