Chondrostereum Purpureum Research Articles

Isolation of aflatoxin biosynthetic inhibitor from Chondrostereum purpureum mushroom culture filtrate

Aflatoxins (AFs) are highly toxic mycotoxins produced by the fungi, Aspergillus flavus and Aspergillus parasiticus. AFs pose severe health risks owing to their acute toxicity and carcinogenic properties. The control of AF contamination remains significantly challenging despite the extensive efforts toward controlling it. Here, we investigated the potential of mushroom extracts as a source of AF biosynthetic inhibitors. The A.parasiticus mutant strain, NFRI-95, that accumulates an AF biosynthesis intermediate, norsolorinic acid, was used in the bioassay to detect the inhibitory activity against AF biosynthesis. The screening of 195 mushroom extracts revealed that the culture filtrate extract of Chondrostereum purpureum exhibited strong inhibitory activity against AF biosynthesis. Next, large-scale culturing of C.purpureum was performed to isolate the compounds accounting for the inhibitory activity. The culture filtrate was extracted with ethyl acetate, after which the active compound was isolated by silica gel column chromatography and preparative high performance liquid chromatography (HPLC). The active compound was identified as cyclo(Val-Pro) by spectroscopic analyses. Further, four stereoisomers of cyclo(Val-Pro) were synthesized by the condensation of the N-Boc derivatives of d- and l-valine with the methyl esters of d- and l-proline. The naturally isolated compound was identified as cyclo(l-Val-l-Pro) by comparing its retention time with those of synthetic compounds by chiral HPLC analysis and CD spectra. The IC50 value of cyclo(L-Val-L-Pro) was 2.4mM, whereas the LD, DL, and DD isomers exhibited weaker activities, with IC50 values of >5mM.

First report of silverleaf caused by Chondrostereum purpureum in hazelnut (Corylus avellana) in Chile.

Hazelnut is among the most important nut crops in Chile, currently covering 46,000 ha. In 2023, the country exported 30,000-ton. In recent years the incidence of plants with internal discoloration, cankers and dieback has been increasing. In some cases, the trees died and had to be removed and, after a year, purple resupinate fruiting bodies were observed growing from the stumps. To determine the etiology of the symptoms and signs, wood samples (n=318) were collected since 2020, from 38 symptomatic orchards from Maule to La Araucanía Regions, primarily from the cvs. Tonda di Giffoni and Lewis. Wood sections 0.5 cm diameter were cut from the symptomatic tissues, disinfected using a sodium hypochlorite (10%) solution, and plated on a quarter-strength acidified potato dextrose agar (aPDA1/4). The plates were incubated and purified on PDA. Subsequently, isolates were identified by morphological and molecular means. Almost half of the isolates (47%) were preliminarily identified as basidiomycetes, based on mycelial features such as the presence of clamp connections, with 45% of them exhibiting abundant whitish cottony fast-growth mycelia, resembling Chondrostereum purpureum (Grinbergs et al., 2020). DNA was extracted and the 500-bp fragment, located between 5S and 18S ribosomal regions, was amplified using APN1 specific primers (Becker et al. 1999), identifying the isolates as C. purpureum. In addition, 5.8S gene of RGM1 (35°13'40.9"S 71°25'14.1"W), RGM2 (36°31'27.95"S 71°46'58.31"W), RGM3 (37°10'54.8"S 72°03'39.6"W), RGM4 (35°19'25.2"S 71°19'54.7"W) and RGM5 (36°35'30.8"S 72°05'18.8"W) isolates, representing different locations within the hazelnut growing area, was amplified using ITS1/ITS4 primers (White et al., 1990). The PCR product was sequenced, and the analysis showed 100% homology among isolates (Genebank codes: PP839283, PP839284, PP839285, PP839286 and PP839287, respectively). To determine the pathogenicity of the isolates, 30-cm healthy cuttings cv. Lewis were inoculated with mycelial plugs, while control shoots were inoculated with sterile agar plugs. Cuttings were vertically arranged in pots with 3-cm water and incubated for 60-d at 22°C. In addition, fresh cuts of 3-y potted plants cv. Lewis were inoculated with mycelial plugs and incubated for 137-d in a shadehouse. After incubation, bark was removed from inoculated cuttings and the length of necrotic lesions was measured. Although discoloration was reproduced by all the isolates in both pathogenicity tests, RGM1 isolate was the most aggressive, causing the complete discoloration of the cuttings and the death of the inoculated plants. To our knowledge this is the first report of C. purpureum causing wood disease in hazelnut. These findings are significant because the disease may not only reduce orchard longevity but also decrease fruit yield and quality, as observed in other fruit crops (Grinbergs et al., 2021).

PHYTOPATHOGENIC WALNUT COMPLEX IN WESTERN FOREST STEPPE OF UKRAINE

A study on the phytopathogenic complex of walnut in the western forest-steppe of Ukraine is presented. Route and sample surveys were carried out during 2020-2023 on the basis of UkrNDSKR IZR (Ukrainian Plant Quarantine Research Station of the Institute of Plant Protection, 7 ha) and village Zvenyachyn, SE "DG PDSS IS" (State Enterprise Experimental Farm of the Transnistrian Research Station of Horticulture of the Institute of Horticulture). During the study, 13 species of fungi were found, of which 6 species belong to the Ascomycota department: Ophiognomonia leptostyla (Fr.) Sogonov (Marssonina juglandis (Lieh.) Magn., Melanconium juglandinum Kunze, Cytospora juglandina Sacc., Nectria cinnabarina (Tode ex Fr. ) (Tubercularia vulgaris Tode), Septoria epicarpii Thüm., Phyllosticta juglandis Sacc. - 7 species: Microstroma juglandis Sacc., Laetiporus sulphureus (Bull.) Bond. et Sing., Pleurotus ostreatus (Jacq .ex Fr.) Ganoderma applanatum Pat., Chondrostereum Purpureum Pers.; 1 type of bacteriosis belonging to the department of Xanthomonas arboricola pv , shoots, branches, trunks, fruits. A laboratory study of plant material with various symptoms of damage showed the predominance of phytopathogenic fungi: Marssonina juglandis (Lieh.) Magn., Phyllosticta juglandis Sacc.; Microstroma juglandis Sacc. and Xanthomonas arboricola pv. juglandis Sacc. The most common and dangerous walnut diseases in the examined territories were: Marssonina juglandis (Lieh.) Magn. and Xanthomonas arboricola pv.. juglandis Key words: walnut, phytopathogenic complex, pathogens, distribution

Plant Fungus Chondrostereum purpureum: Also infects humans

Chondrostereum purpureum, is a plant fungus causing silver leaf disorder of plant life, especially of the rose family. It attacks in the main species of the rose family. Hosts with compromised immune system are maximum liable to fungal infection but healthy and immune competent individuals also are frequently pronounced to have fungal infections. In this situation the infections can be related to exposure to a huge inoculum.

P187 Paratracheal abscess by plant fungus Chondrostereum purpureum. First case report of human infection

Poster session 2, September 22, 2022, 12:30 PM - 1:30 PM ObjectiveTo identify the etiological agent of paratracheal abscess applying molecular techniques.MethodsA 61-year-old male, plant Mycologist, who specially works with mushrooms presented to the OPD with hoarseness of voice and difficulty in swallowing for the last 3 months. CT scan demonstrated the presence of a right paratracheal abscess. CT-guided aspiration of the abscess was performed. The pus was sent for microbiological evaluation.ResultsThe pus culture done on Sabouraud dextrose agar grew a creamy pasty colony with buff-colored pigmentation on reverse side (Fig. 1). On LCB mount preparation it was found to be a yeast-like structure with slender hyphae as shown in Fig. 2. The fungus could not be identified phenotypically, so it was sent to the ‘WHO Collaborating Centre for Reference and Research on Fungi of Medical importance’. It was identified as Chondrostereum purpureum by DNA sequencing. Patient was treated with oral voriconazole following drainage of the pus and the outcome was favorable. The patient denied having worked with such a plant pathogen but he confirmed d that he was working with decaying material and other plant fungi for a long time as part of his research activities.ConclusionSilver leaf is a fungal disease of trees caused by the fungus plant pathogen Chondrostereum purpureum. The disease is progressive and often fatal for the plants. It is spread by airborne spores landing on freshly exposed sapwood. No human infection was reported till date. The case report demonstrates the crossover of plant pathogens into humans when working in close contact with plant fungi.

Comparative Efficacy of Chondrosterum purpureum and Chemical Herbicides for Control of Resprouts in Tanoak and Bay Laurel

The invasive Oomycete pathogen Phytophthora ramorum has killed millions of susceptible oak and tanoak trees in California and southern Oregon forests and is responsible for losses in revenue to the nursery industry through mitigation activities. In addition, infestation of forests in the United Kingdom by this organism has resulted in the destruction of many hectares of larch plantations. Resprouting stumps can be a reservoir for the inoculum of P. ramorum persisting on a site. In areas where the application of herbicides is not permitted, a biocontrol treatment would be an indispensable alternative. Treatment of stumps with the sap-rotting fungus Chondrostereum purpureum (Pers.) Pouzar has been shown to be an effective tool for the suppression of resprouting on several species, most notably red alder. In this project, the ability of C. purpureum to suppress resprouting was evaluated on stumps of two host species, tanoak (Notholithocarpus densiflorus) and California bay laurel (Umbellularia californica). Laboratory testing of three California isolates of C. purpureum indicated that the fungus can colonize bay laurel stems. Field trials were established near Brookings, Oregon, on tanoak and on bay laurel near Soquel, California. Early results of field testing showed that C. purpureum was able to colonize the stumps of tanoak following treatment and was found to occur naturally on tanoak logs and stumps. Formulations of C. purpureum appear to have some effect on reducing sprout survival in tanoak, but the most effective and rapid treatment for this host is the hack and squirt method of applying the herbicide imazapyr. Sprayed herbicide prevents sprouting on bay laurel, and there was evidence that resprouting was inhibited on stumps treated with C. purpureum. Over time, applications of C. purpureum may be a more permanent solution as the stumps begin to decay.

Silverleaf (Chondrostereum purpureum) Effects on Japanese Plum (Prunus salicina).

Silverleaf is an important fungal trunk disease of fruit crops, such as Japanese plum (Prunus salicina). It is known that infection by Chondrostereum purpureum results in discolored wood, “silvered” foliage, and tree decline. However, effects on fruit yield and quality have not been assessed. Therefore, the objectives of this study were to determine C. purpureum pathogenicity on P. salicina and the effects on physiology, fruit yield, and quality, in Chile, in 2019 and 2020. Wood samples from affected plum trees were collected in the Chilean plum productive area. Fungi were isolated by plating wood sections from the necrosis margin on culture media. Morphological and molecular characteristics of the isolates corresponded to C. purpureum (98%). Representative isolates were inoculated from healthy plum plants and after 65-d incubation, wood necrotic lesions and silver leaves were visible. Fungi were reisolated, fulfilling Koch’s postulates. To determine Silverleaf effects, xylem water potential and fruit yield and quality were measured in healthy and Silverleaf-diseased plum trees ‘Angeleno’. Water potential was altered in diseased trees, and fruit yield was reduced by 51% (2019) and by 41% (2020) compared to fruit from healthy trees. Moreover, cover-colour, equatorial-diameter, and weight were reduced, and fruit were softer, failing to meet the criteria to be properly commercialized and exported to demanding markets.

Cutlink Cleaning Head with a Spreading Feature for Biological Sprout Control

The ability of deciduous trees to sprout efficiently after cutting is problematic in young forests where the target is to cultivate coniferous trees for industry. Since the use of chemicals has been restricted, new alternatives are needed. One potential and environmentally friendly option is biological sprout control that is based on the use of a white-rot fungus, Chondrostereum purpureum (Pers. Ex Fr.) Pouzar. This method has been efficient in earlier investigations when performed manually, but efficient, fully mechanized devices which are able to cut and treat stumps with a fungus are still unavailable. Therefore, the efficacy of biological sprout control conducted with a Cutlink cleaning head equipped with a spreading feature was studied in two young Norway spruce (Picea abies (L.) H. Karst.) forests in central Finland.Sample plots for the control (cutting deciduous saplings only) and fungal treatment (cutting and spreading fungal inoculum on fresh stump surfaces) were established, and the ability of the Cutlink cleaning head in preventing sprouting of silver and downy birch (Betula pendula Roth and B. pubescens Ehrh., respectively) in the sample plots was investigated for two years.In the near vicinity of cultivated Norway spruce, the proportion of cut deciduous saplings varied from 50–60% after the Cutlink operation. The average mortality of silver and downy birch stumps in the fungal treatment plots was ca. 40%, while stump mortality in the control, i.e., cutting only, was only ca. 13%, after two years. Stump mortality increased up to 73% if the stumps did not include old branches, i.e., the stump was cut to a low enough height.These results confirmed that the Cutlink cleaning head is a potential tool in young stand management operation but further development will be needed in working methods in order to achieve lower stump heights (no branches on the stump) and also to increase the proportion of cut saplings.

Covalent Immobilization of Chondrostereum purpureum Endopolygalacturonase on Ferromagnetic Nanoparticles: Catalytic Properties and Biotechnological Application.

Pectinases are widely used in a variety of industrial processes. However, their application is limited by low catalytic processivity, reduced stability, high cost, and poor re-use compatibility. These drawbacks may be overcome by enzyme immobilization with ferromagnetic nanoparticles, which are easily recovered by a magnetic field. In this work, an endopolygalacturonase from Chondrostereum purpureum (EndoPGCp) expressed in Pichia pastoris was immobilized on glutaraldehyde-activated chitosan ferromagnetic nanoparticles (EndoPGCp-MNP) and used to supplement a commercial enzyme cocktail. No significant differences in biochemical and kinetic properties were observed between EndoPGCp-MNP and EndoPGCp, although the EndoPGCp-MNP showed slightly increased thermostability. Cocktail supplementation with EndoPGCp-MNP increased reducing sugar release from orange wastes by 1.8-fold and showed a synergistic effect as compared to the free enzyme. Furthermore, EndoPGCp-MNP retained 65% of the initial activity after 7 cycles of re-use. These properties suggest that EndoPGCp-MNP may find applications in the processing of pectin-rich agroindustrial residues.

Endophytic Microorganisms Associated with Reversion of Silverleaf Disease Symptoms in Apple

Silverleaf is caused by the fungus Chondrostereum purpureum, which produces wood necrosis and foliar silvering in woody plants. Field observations and studies in apple have shown the reversion of foliar symptoms. Since plants were clones and received identical agronomical management, it was hypothesized that reversion is driven by endophytic microbiota. Thus, the objectives of this study were to compare healthy, diseased and reverted plants with respect to their physiology, endophytic microbial communities, antagonistic ability of their endophytes against C. purpureum and defense-genes-expression. Water-potential, stomatal-conductance, chlorophyll-content and fluorescence were measured. Endophytic bacterial and fungal DNA were analyzed by DGGE, and communities richness and similarity were calculated. Wood cores were collected and bacterial and fungal endophytes were isolated and confronted with C. purpureum virulent strains in dual-culture assays. Defense-genes-expression were measured by qPCR. Results indicated that there were no differences in physiological parameters between healthy and reverted plants, except for fluorescence, and both type of plants differed from diseased ones. Bacterial and fungal communities richness were similar in healthy and reverted plants, and higher than in diseased ones. Endophytes from reverted and healthy plants showed high antagonism to C. purpureum. Furthermore, NPR1-gene-expression was upregulated in reverted plants, while PAL and PGIP showed higher values in diseased plants. Overall, physiological, molecular and microbial characteristics were similar between healthy and reverted plants, and both differed from diseased ones. Therefore, reversion of symptoms is associated with changes in the endophytic microbiota, which seems to be a promising source of biological control agents against C. purpureum.

Long-term effects of biological sprout control of unwanted hardwoods on conifer sites

Long-term investigations revealing the effects of a decay fungus, Chondrostereum purpureum (Pers. Ex Fr.) Pouzar on competition between deciduous and conifer tree species in young forests are missing. Therefore, the effects of three different sprout control treatments were tested in young Norway spruce (Picea abies (L.) H. Karst.) and Scots pine (Pinus sylvestris L.) stands by evaluating sprouting ability of deciduous tree stumps, and competition level around cultivated conifers five years after the treatments. Sprouting control was performed (i) by cutting only (control), and ii) by applying low-concentration (dilution 1:400) or iii) high-concentration (dilution 1:100) C. purpureum preparates (mycelial solutions) on stumps immediately after cutting. Deciduous saplings were cut, and fungal inoculum was applied by spreading it onto freshly cut stump surfaces. Following high-concentration fungal treatment, the number of young deciduous trees cut in the treatment was by 25% lower compared to control; moreover, the number of sprouts per stump was also significantly negatively affected by the fungal treatment. As a result, the number of cases when competing deciduous trees occurred within a 1 m sample plot around the investigated conifers was 40% lower following high-concentration fungal treatment than in the control, resulting in better height and diameter development of conifers. Thus, additional sprout control is not necessarily needed after the high-concentration fungal treatment.

Metal concentrations of wild mushroom species collected from Belgrad forest (Istanbul, Turkey) with their health risk assessments.

Wild edible mushrooms are very popular for both their flavors and nutritional values. However, some mushroom species can be harmful to human health as they accumulate some elements in excessive amounts. The aim of this study was to determine the concentrations of Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, P, Se, and Zn of some wild edible (Agaricus arvensis, A. bitorquis, A. sylvaticus, Amanita vaginata, Armillaria mellea, Clavariadelphus pistillaris, Clitocybe nebularis, Clitopilus prunulus, Hygrophorus marzuolus, H. russula, Lactarius volemus, Lycoperdon molle, and Macrolepiota mastoidea) and non-edible mushroom species (A. citrina, Auricularia mesenterica, Chanterellus melanoxeros, Chondrostereum purpureum, Clathrus ruber, L. controversus, L. helvus, and L. zonarius) collected from Belgrad forest (Istanbul, Turkey). Daily intakes of element (DIE) and health risk index (HRI) values of the edible mushroom species were also calculated. The concentrations of the elements in question were determined to be in the ranges of 9.7-556.8, 2.5-2226.7, 0.06-2.52, 0.03-13.17, 3.74-100.19, 13.3-507.4, 2635.0-28614.0, 493.0-2412.0, 6.97-3150.73, 0.29-13.26, 0.38-3.67, and 9.1-293.8 mg/kg, respectively. The Cd concentration of H. russula (DIE: 1.08, HRI: 1.08), Cr concentration of C. nebularis (DIE: 5.64, HRI: 1.88), and the Cu concentration of M. mastoidea (DIE: 42.94, HRI: 1.07) were above the reference values. The results showed that the long-term consumption of H. russula, C. nebularis, and M. mastoidea collected from Belgrad forest can have a negative impact on human health. Therefore, it was concluded that the element concentrations of edible wild mushrooms in this region should be examined periodically.

The effect of a biocontrol fungus Chondrostereum purpureum on sprouting of rowan (Sorbus aucuparia) at different application times

In Southern Finland, rowan (Sorbus aucuparia L.) forms local thickets in young forests where it competes with more valuable conifers. Therefore, these thickets are regularly cut to provide more growing space for conifers. This has been inefficient at preventing excessive sprouting and therefore, new alternatives have been investigated. One of the potential options is to utilize a decay fungus Chondrostereum purpureum (Pers. ex Fr.) Pouzar for controlling sprouting. Spreading mycelia of this fungal species on freshly cut stumps starts a decay process in exposed wood and thus prevents sprouting. In this study, the ability of rowan to sprout after the fungal treatment was investigated at different application times from early spring to late autumn. Three years after the treatment, stump mortality was highest (ca. 40%) among stumps treated in summer and lowest in stumps treated in early spring or late autumn (ca. 20%). Furthermore, sprouts were significantly reduced in stumps treated in summer than in early spring or late autumn. The results indicate that rowan is capable of tolerating fungal infection better in early spring and late autumn than in summer, possibly because in early spring and late autumn resources available for regrowth are in belowground parts of a tree, unlike in summer when nutrients are transported within the stem to leaves and inflorescences. Thus, in rowan, the best sprout control efficacy can be achieved when performed in summer.

Rainstorm effects on the biocontrol efficacy of the decay fungus Chondrostereum purpureum against birch sprouting in boreal forests

In forest regeneration areas, alongside roads and railways, under electric power lines and above gas pipe lines, there is a need for regular sprout control. A biocontrol method against broadleaved sprouting with formulations including the decay fungus Chondrostereum purpureum (Pers. Ex Fr.) Pouzar has been shown to be effective. Yet, heavy rain during spreading of this fungal inoculum on freshly cut stumps may affect the efficacy of the treatment, i.e., stump mortality during the following years. Thus, we performed an experiment where freshly cut birch stump surfaces (Betula pendula Roth and Betula pubescens Ehrh.) were treated with fungal inoculum under heavy irrigation and without it. Furthermore, two different adjuvants which aimed to fix the fungal inoculum to freshly cut stumps during irrigation and to protect against solar radiation were tested. Our results revealed that the artificial rainstorm treatment caused a delay in the efficacy of C. purpureum, but after three growing seasons, there was no significant difference in the mortality of birch stumps treated under irrigation or without it (stump mortalities 74 and 86%, respectively). Adjuvants did not improve the efficacy in stumps treated under irrigation nor in those treated without irrigation.Key Points• Heavy rain delayed the sprout control efficacy of a fungus Chondrostereum purpureum.• Final efficacy of formulations was the same in wet and dry conditions.• No additional adjuvants are needed to improve formulations.

A PCR-Based Method for the Rapid Detection of Chondrostereum purpureum in Apple.

Silverleaf caused by the basidiomycete Chondrostereum purpureum affects numerous woody species, including fruit tree crops like apple, resulting in wood necrosis and foliar silvering. There are no curative alternatives for this disease, and its management is by prevention methods. Therefore, the aim of this study was to develop a rapid diagnostic tool for the detection and identification of C. purpureum directly from woody tissues to help distinguish the pathogen from other basidiomycetes that are commonly found on apple. The silverleaf pathogen was isolated from different hosts and locations, and Koch's postulates were performed by inoculating the isolates on apple cuttings and measuring internal necrosis. A previously described APN 1 pair of primers specificity was also tested against 25 C. purpureum isolates in this study, using other wood rotting species as negative controls. Seven virulent isolates were inoculated on apple cuttings, and DNA was extracted from the cuttings' sawdust and amplified using APN 1, after 22 days of incubation. To prove the efficiency of the method in the field, DNA from healthy nursery plants inoculated with two virulent isolates, and naturally infected plants showing different levels of foliar symptoms, were tested. Presence of the fungus was verified by reisolation on APDA in all assays. Koch's postulates indicated that all C. purpureum isolates were pathogenic, showing different virulence levels, and APN 1 primers were able to discriminate them from other basidiomycetes. The method was also able to detect C. purpureum from artificially inoculated plants as well as naturally infected ones, demonstrating that the protocol may become a rapid minimally destructive diagnostic tool to detect the pathogen without the need to isolate it from tissues, and thus taking measures to prevent its dissemination.

The biocontrol efficacy of Chondrostereum purpureum is not sensitive to prevailing environmental conditions in boreal forests

Sprouting of deciduous trees is problematic in forest regeneration areas, alongside roads and railways, under electric power lines and above gas pipe lines. A decay fungus Chondrostereum purpureum is a potential biocontrol agent against sprouting of deciduous trees. However, before this method can be utilized in practice, the effects of environmental factors on the efficacy of the fungus, i.e., its ability to cause stump mortality, should be understood. Thus, in this study, the effects of environmental factors on the efficacy of C. purpureum in controlling birch stump sprouting were investigated. Fungal inoculum was spread on 342 freshly cut birch (Betula pendula and B. pubescens) stumps at 17 sites, which were thereafter used to investigate the effects of solar radiation, temperature, precipitation, and soil properties on the efficacy of C. purpureum treatment. In the control plots, 318 birches were cut but no fungal inoculum was spread on their freshly cut stumps. The results revealed that solar radiation had no effect on the mortality of treated birch stumps, but an increasing proportion of hot days after the fungal treatment and an increase in precipitation within one week prior to the treatment reduced the mortality rate of stumps by the end of the first growing season following stump treatment. Furthermore, an increase in precipitation after the treatment and high soil moisture were also related to an increase in stump mortality. However, these effects were only temporary as by the end of the second growing season only precipitation that has occurred prior to the treatment had slight effect on birch stump mortality, while other investigated environmental conditions, i.e., proportion of hot days, amount of precipitation after the treatment and soil moisture, had no effect. Furthermore, application of the fungal inoculum immediately after cutting was essential for efficient sprout control. Even a delay of 15–30 min has significantly reduced stump mortality rates. Taken together, this study revealed that the presented method of biological stump sprouting control is not very sensitive to the investigated environmental conditions, suggesting that it can be used also during hot and rainy periods as long as requirement for a minimal delay between the cutting of trees and stump treatment is considered.

The efficacy of Chondrostereum purpureum in sprout control of birch during mechanized pre-commercial thinning

The efficacy of mechanized pre-commercial thinning (PCT) done by a lightweight mini-harvester Tehojätkä together with the Chondrostereum purpureum (Pers. ex Fr.) Pouzar fungal treatment (dilutions 1:100, 1:200, 1:400) and control (cutting only) was studied for three years. The efficacy of the fungal treatment was defined as capability to prevent sprouting of birch (Betula pendula Roth. and B. pubescens Ehrh.). The fungal treatment resulted in higher stump mortality and lower number of sprouts but it did not have a clear effect on the maximum height of stump sprouts. However, mortalities obtained in this study (34.1%, 26.8%, and 25.6% for dilutions 1:100, 1:200, and 1:400, respectively) were notably lower compared to previous studies which indicate that the accuracy of the spreading mechanism was not satisfactory. We conclude that it is possible to decrease stump sprouting with the fully mechanized fungal treatment but putting this implementation into practice needs more testing to increase efficacy.

First Report of Silverleaf Disease Caused by Chondrostereum purpureum on Murta (Ugni molinae) in Chile

First Report of Silverleaf Disease Caused by <i>Chondrostereum purpureum</i> on Murta (<i>Ugni molinae</i>) in Chile

Genome and secretome of Chondrostereum purpureum correspond to saprotrophic and phytopathogenic life styles.

The basidiomycete Chondrostereum purpureum (Silverleaf fungus) is a saprotroph and plant pathogen commercially used for combatting forest “weed” trees in vegetation management. However, little is known about its lignocellulose-degrading capabilities and the enzymatic machinery that is responsible for the degradative potential, and it is not yet clear to which group of wood-rot fungi it actually belongs. Here, we sequenced and analyzed the draft genome of C. purpureum (41.2 Mbp) and performed a quantitative proteomic approach during growth in submerged and solid-state cultures based on soybean meal suspension or containing beech wood supplemented with phenol-rich olive mill residues, respectively. The fungus harbors characteristic lignocellulolytic hydrolases (GH6 and GH7) and oxidoreductases (e.g. laccase, heme peroxidases). High abundance of some of these genes (e.g. 45 laccases, nine GH7) can be explained by gene expansion, e.g. identified for the laccase orthogroup ORTHOMCL11 that exhibits a total of 18 lineage-specific duplications. Other expanded genes families encode for proteins more related to a pathogenic lifestyle (e.g. protease and cytochrome P450s). The fungus responds to the presence of complex growth substrates (lignocellulose, phenolic residues) by the secretion of most of these lignocellulolytic and lignin-modifying enzymes (e.g. alcohol and aryl alcohol oxidases, laccases, GH6, GH7). Based on the genetic and enzymatic constitution, we consider the ‘marasmioid’ fungus C. purpureum as a ‘phytopathogenic’ white-rot fungus (WRF) that possesses a complex extracellular enzyme machinery to accomplish efficient lignocellulose degradation during both saprotrophic and phytopathogenic life phases.

The efficacy of &lt;i&gt;Chondrostereum purpureum&lt;/i&gt; against sprouting of deciduous species after mechanized pre-commercial thinning

The use of a white-rot fungus, (Pers. Ex Fr.) Pouzar, as a biocontrol agent against sprouting has been studied with good results. The aim of the study was to investigate the efficacy of two pre-commercial thinning machines, Tehojätkä and Mense, to spread an inoculum of as a biocontrol agent on freshly cut birch ( Roth and Ehrh.), European aspen ( L.), rowan ( L.), and goat willow ( L.) stumps (the fungal treatment) and compare that to the control (cutting only, done by Tehojätkä). Efficacy was investigated in terms of stump mortality and the number of sprouts per stump. This study was conducted in one stand and sprouting was investigated for three years after treatment. The fungal treatment resulted in higher mortality of stumps (34.0% for Tehojätkä and 41.5% for Mense after three years), compared to the control (13.4%). However, the fungal treatment did not decrease the number of sprouts per stump compared to the control. The low occurrence of basidiomata indicates that the accuracy of the spreading mechanism was not satisfactory, causing low mortality figures for the fungal treatment compared to previous studies. In the future, this mechanized method may provide a promising alternative in sprout control if the spreading mechanisms, the accuracy of the treatment, and consequently the efficacy could be improved.Chondrostereum purpureumC. purpureumBetula pendulaB. pubescensPopulus tremulaSorbus aucupariaSalix caprea