The maximum carboxylation rate of Rubisco affects CO2 refixation in temperate broadleaved forest trees.

Mesophyll resistance to CO2 diffusion (rm) and the maximum carboxylation rate of Rubisco (Vcmax) affect photosynthetic rates, and can potentially also influence the percentage of respiratory and photorespiratory CO2 being refixated (Pr) by mesophyll cells. Here we investigated how various leaf anatomical traits (e.g. leaf mass per area [LMA] and leaf dry matter content [LDMC]) influenced rm in leaves of mature forest trees. We further explored how rm and Vcmax in turn affected Pr, and if these traits varied among species and leaves along a light gradient. Photosynthetic CO2 response of leaves grown in high-, medium-, and low-light environments was measured, from Pinus sylvestris [Scots pine], Picea abies [Norway spruce], Quercus robur [English oak], and Betula pendula [Silver birch] in southern Sweden. A modified version of the Farquhar-von Caemmerer-Berry model was fitted to the leaf gas exchange data to estimate Vcmax, rm and Pr. We found that of all leaf traits measured, only LMA for Q. robur was significantly higher in leaves from high-light environments. When comparing species, both rm and LMA were significantly higher in the conifers, and rm had a negative correlation with Vcmax. We found that Pr was similar between different species and functional groups, with an average of 73.2% (and SD of ±10.4) across all species. There was a strong, positive correlation between Pr and Vcmax in broadleaves, and we hypothesise that this effect might derive from a higher CO2 drawdown near Rubisco in leaves with high Vcmax.

Sequencing of anthocyanin synthesis-related enzyme genes and screening of reference genes in leaves of four dominant subtropical forest tree species.

The young leaves generally accumulate a certain concentration anthocyanins in the dominant species of the subtropical forest, and the changes of anthocyanin synthesis-related enzyme genes expression levels had an important effect on the study photoprotection of anthocyanins in the young leaves of subtropical forests. The determination of anthocyanin synthesis-related enzyme gene sequences and the selection of appropriate reference genes provide a basis for analyzing the functional properties of anthocyanins. In this study, four dominant subtropical forest species (i.e., Schima superba, Castanopsis fissa, Acmena acuminatissima, Cryptocarya concinna) were taken as materials. To obtain the correct nucleotide sequences of anthocyanin-related enzymes, the nucleotide sequences of CHS, DFR and ANS in each dominant species were obtained by sequencing and comparison. Then, to select the most stable reference genes for leaves at different developmental stages and different light conditions, the expression levels of six reference genes, including 18S, Actin, GAPDH, TUB, EF1 and UBQ, were studied by real-time fluorescent quantitative PCR (qRT-PCR), and reference gene stability was analyzed by GeNorm and NormFinder software. The results showed that the expression level of Actin was the most stable in S. superba, A. acuminatissima and C. concinna, and the expression level of GAPDH was the most stable in C. fissa. Finally, the expression levels of the anthocyanin synthesis genes CHS, DFR and ANS were analyzed and found to be consistent with the accumulation trend of anthocyanins in leaves. This study has important theoretical and practical significance for future research into the expression of anthocyanin synthesis-related enzyme genes in the dominant tree species in subtropical forests and reveals that anthocyanin has a photoprotective effect for young leaves in high-light environments.

Identification of oxidosqualene cyclases from the medicinal legume tree Bauhinia forficata: a step toward discovering preponderant α-amyrin-producing activity.

Triterpenoids are widely distributed among plants of the legume family. However, most studies have focused on triterpenoids and their biosynthetic enzymes in model legumes. We evaluated the triterpenoid aglycones profile of the medicinal legume tree Bauhinia forficata by gas chromatography-mass spectrometry. Through transcriptome analyses, homology-based cloning, and heterologous expression, we discovered four oxidosqualene cyclases (OSCs) which are responsible for the diversity of triterpenols in B. forficata. We also investigated the effects of the unique motif TLCYCR on α-amyrin synthase activity. B. forficata highly accumulated α-amyrin. We discovered an OSC with a preponderant α-amyrin-producing activity, which accounted for at least 95% of the total triterpenols. We also discovered three other functional OSCs (BfOSC1, BfOSC2, and BfOSC4) that produce ß-amyrin, germanicol, and cycloartenol. Furthermore, by replacing the unique motif TLCYCR from BfOSC3 with the MWCYCR motif, we altered the function of BfOSC3 such that it no longer produced α-amyrin. Our results provide new insights into OSC cyclization, which is responsible for the diversity of triterpenoid metabolites in B. forficata, a non-model legume plant.

In Silico Genome-Wide Analysis of Respiratory Burst Oxidase Homolog (RBOH) Family Genes in Five Fruit-Producing Trees, and Potential Functional Analysis on Lignification of Stone Cells in Chinese White Pear.

: The accumulation of lignin in fruit has a significant negative impact on the quality of fruit-producing trees, and in particular the lignin formation stimulates the development of stone cells in pear fruit. Reactive oxygen species (ROS) are essential for lignin polymerization. However, knowledge of the RBOH family, a key enzyme in ROS metabolism, remains unknown in most fruit trees. In this study, a total of 40 RBOHs were identified from five fruit-producing trees (Pyrusbretschneideri, Prunuspersica, Citrussinensis, Vitisvinifera, and Prunusmume), and 10 of these sequences came from Pyrusbretschneideri. Multiple sequence alignments revealed that all 10 PbRBOHs contained the NADPH_Ox domain and the six alpha-helical transmembrane domains (TM-I to TM-VI). Chromosome localization and interspecies phylogenetic tree analysis showed that 10 PbRBOHs irregularly distributed on 8 chromosomes and 3 PbRBOHs (PbRBOHA, PbRBOHB, and PbRBOHD) are closely related to known lignification-related RBOHs. Furthermore, hormone response pattern analysis showed that the transcription of PbRBOHs is regulated by SA, ABA and MeJA. Reverse transcription-quantitative real-time polymerase chain reaction (qRT-PCR) and transcriptome sequencing analysis showed that PbRBOHA, PbRBOHB, and PbRBOHD accumulated high transcript abundance in pear fruit, and the transcriptional trends of PbRBOHA and PbRBOHD was consistent with the change of stone cell content during fruit development. In addition, subcellular localization revealed that PbRBOHA and PbRBOHD are distributed on the plasma membrane. Combining the changes of apoplastic superoxide (O2.-) content and spatio-temporal expression analysis, these results indicate that PbRBOHA and PbRBOHD, which are candidate genes, may play an important role in ROS metabolism during the lignification of pear stone cells. This study not only provided insight into the molecular characteristics of the RBOH family in fruit-producing trees, but also lays the foundation for studying the role of ROS in plant lignification.

The function of two type II metacaspases in woody tissues of Populus trees.

Metacaspases (MCs) are cysteine proteases that are implicated in programmed cell death of plants. AtMC9 (Arabidopsis thaliana Metacaspase9) is a member of the Arabidopsis MC family that controls the rapid autolysis of the xylem vessel elements, but its downstream targets in xylem remain uncharacterized. PttMC13 and PttMC14 were identified as AtMC9 homologs in hybrid aspen (Populus tremula × tremuloides). A proteomic analysis was conducted in xylem tissues of transgenic hybrid aspen trees which carried either an overexpression or an RNA interference construct for PttMC13 and PttMC14. The proteomic analysis revealed modulation of levels of both previously known targets of metacaspases, such as Tudor staphylococcal nuclease, heat shock proteins and 14-3-3 proteins, as well as novel proteins, such as homologs of the PUTATIVE ASPARTIC PROTEASE3 (PASPA3) and the cysteine protease RD21 by PttMC13 and PttMC14. We identified here the pathways and processes that are modulated by PttMC13 and PttMC14 in xylem tissues. In particular, the results indicate involvement of PttMC13 and/or PttMC14 in downstream proteolytic processes and cell death of xylem elements. This work provides a valuable reference dataset on xylem-specific metacaspase functions for future functional and biochemical analyses.

Analysis of Fresh Sap Collected from Ryukyu Lacquer Tree.

The chemical structure of fresh lacquer sap collected from a lacquer tree growing in Nago City of Okinawa, Japan, was analyzed by gas chromatography/mass-spectrometry (GC/MS) and nuclear magnetic resonance (NMR). The results showed that Nago lacquer is laccol lacquer and its major components are 3-(heptadeca-10Z,13E,15E-trienyl)catechol, 3-(heptadeca-10Z,13E-dienyl)catechol, 3-(heptadeca-14Z-enyl)catechol, and 3-(heptadeca-12Z-enyl)catechol, which are similar to the components of Vietnamese lacquer. It showed higher laccase activity at pH 5 - 8 and better low temperature adaptability than Vietnamese lacquer. The Nago lacquer reached a dust free dry (DF) condition after 6 h, but Vietnamese lacquer did not. However, both were able to achieve harden dry (HD) in 24 h at 25°C, 80% relative humidity. In order to identify the lacquer provenance, the strontium isotope ratio was analyzed. The strontium isotope ratio (87Sr/86Sr) of Nago lacquer was 0.7110, which is different from the 0.7450 of Vietnamese lacquer.

Four terpene synthases contribute to the generation of chemotypes in tea tree (Melaleuca alternifolia).

BACKGROUND: Terpene rich leaves are a characteristic of Myrtaceae. There is significant qualitative variation in the terpene profile of plants within a single species, which is observable as "chemotypes". Understanding the molecular basis of chemotypic variation will help explain how such variation is maintained in natural populations as well as allowing focussed breeding for those terpenes sought by industry. The leaves of the medicinal tea tree, Melaleuca alternifolia, are used to produce terpinen-4-ol rich tea tree oil, but there are six naturally occurring chemotypes; three cardinal chemotypes (dominated by terpinen-4-ol, terpinolene and 1,8-cineole, respectively) and three intermediates. It has been predicted that three distinct terpene synthases could be responsible for the maintenance of chemotypic variation in this species. RESULTS: We isolated and characterised the most abundant terpene synthases (TPSs) from the three cardinal chemotypes of M. alternifolia. Functional characterisation of these enzymes shows that they produce the dominant compounds in the foliar terpene profile of all six chemotypes. Using RNA-Seq, we investigated the expression of these and 24 additional putative terpene synthases in young leaves of all six chemotypes of M. alternifolia. CONCLUSIONS: Despite contributing to the variation patterns observed, variation in gene expression of the three TPS genes is not enough to explain all variation for the maintenance of chemotypes. Other candidate terpene synthases as well as other levels of regulation must also be involved. The results of this study provide novel insights into the complexity of terpene biosynthesis in natural populations of a non-model organism.

RNA extraction from decaying wood for (meta)transcriptomic analyses.

Wood decomposition is a key step of the terrestrial carbon cycle and is of economic importance. It is essentially a microbiological process performed by fungi and to an unknown extent by bacteria. To gain access to the genes expressed by the diverse microbial communities participating in wood decay, we developed an RNA extraction protocol from this recalcitrant material rich in polysaccharides and phenolic compounds. This protocol was implemented on 22 wood samples representing as many tree species from 11 plant families in the Angiosperms and Gymnosperms. RNA was successfully extracted from all samples and converted into cDNAs from which were amplified both fungal and bacterial protein coding genes, including genes encoding hydrolytic enzymes participating in lignocellulose hydrolysis. This protocol applicable to a wide range of decomposing wood types represents a first step towards a metatranscriptomic analysis of wood degradation under natural conditions.

Expression and Characterization of Windmill Palm Tree (Trachycarpus fortunei) Peroxidase by Pichia pastoris.

Currently, commercial plant peroxidases are all native and are isolated from plants such as horseradish and soybean. No recombinant plant peroxidase products have been available on the commercial market. The gene encoding peroxidase was cloned from windmill palm tree leaves. The codon-optimized gene was transformed into Pichia pastoris for expression. The recombinant windmill palm tree peroxidase (rWPTP) expressed by P. pastoris showed high stability under pH 2-10 and temperatures up to 70 °C to many metallic salts and organic solvents. The substrate specificity of WPTP was determined, and among the substrates tested, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) was most suitable for WPTP. The Michaelis constants with the substrates H2O2 and ABTS were 4.6 × 10-4 and 1.6 × 10-4 M, respectively. The rWPTP expressed in P. pastoris may be a suitable enzyme for the biosynthesis of polymers because of its high stability and activity under acidic conditions.

Overexpression of Populus trichocarpa CYP85A3 promotes growth and biomass production in transgenic trees.

Brassinosteroids (BRs) are essential hormones that play crucial roles in plant growth, reproduction and response to abiotic and biotic stress. In Arabidopsis, AtCYP85A2 works as a bifunctional cytochrome P450 monooxygenase to catalyse the conversion of castasterone to brassinolide, a final rate-limiting step in the BR-biosynthetic pathway. Here, we report the functional characterizations of PtCYP85A3, one of the three AtCYP85A2 homologous genes from Populus trichocarpa. PtCYP85A3 shares the highest similarity with AtCYP85A2 and can rescue the retarded-growth phenotype of the Arabidopsis cyp85a2-2 and tomato dx mutants. Constitutive expression of PtCYP85A3, driven by the cauliflower mosaic virus 35S promoter, increased the endogenous BR levels and significantly promoted the growth and biomass production in both transgenic tomato and poplar. Compared to the wild type, plant height, shoot fresh weight and fruit yield increased 50%, 56% and 43%, respectively, in transgenic tomato plants. Similarly, plant height and stem diameter increased 15% and 25%, respectively, in transgenic poplar plants. Further study revealed that overexpression of PtCYP85A3 enhanced xylem formation without affecting the composition of cellulose and lignin, as well as the cell wall thickness in transgenic poplar. Our finding suggests that PtCYP85A3 could be used as a potential candidate gene for engineering fast-growing trees with improved wood production.

δ18O in the tropical conifer Agathis robusta records ENSO-related precipitation variations.

Long-lived trees from tropical Australasia are a potential source of information about internal variability of the El Niño-Southern Oscillation (ENSO), because they occur in a region where precipitation variability is closely associated with ENSO activity. We measured tree-ring width and oxygen isotopic composition (δ18O) of α-cellulose from Agathis robusta (Queensland Kauri) samples collected in the Atherton Tablelands, Queensland, Australia. Standard ring-width chronologies yielded low internal consistency due to the frequent presence of false ring-like anatomical features. However, in a detailed examination of the most recent 15 years of growth (1995-2010), we found significant correlation between δ18O and local precipitation, the latter associated with ENSO activity. The results are consistent with process-based forward modeling of the oxygen isotopic composition of α-cellulose. The δ18O record also enabled us to confirm the presence of a false growth ring in one of the three samples in the composite record, and to determine that it occurred as a consequence of anomalously low rainfall in the middle of the 2004/5 rainy season. The combination of incremental growth and isotopic measures may be a powerful approach to development of long-term (150+ year) ENSO reconstructions from the terrestrial tropics of Australasia.

Tree species composition influences enzyme activities and microbial biomass in the rhizosphere: a rhizobox approach.

Monoculture causes nutrient losses and leads to declines in soil fertility and biomass production over successive cultivation. The rhizosphere, a zone of usually high microbial activities and clearly distinct from bulk soil, is defined as the volume of soil around living roots and influenced by root activities. Here we investigated enzyme activities and microbial biomass in the rhizosphere under different tree compositions. Six treatments with poplar, willow, and alder mono- or mixed seedlings were grown in rhizoboxes. Enzyme activities associated with nitrogen cycling and microbial biomass were measured in all rhizosphere and bulk soils. Both enzyme activities and microbial biomass in the rhizosphere differed significantly tree compositions. Microbial biomass contents were more sensitive to the changes of the rhizosphere environment than enzyme activities. Tree species coexistence did not consistently increase tested enzyme activities and microbial biomass, but varied depending on the complementarities of species traits. In general, impacts of tree species and coexistence were more pronounced on microbial composition than total biomass, evidenced by differences in microbial biomass C/N ratios stratified across the rhizosphere soils. Compared to poplar clone monoculture, other tree species addition obviously increased rhizosphere urease activity, but greatly reduced rhizosphere L-asparaginase activity. Poplar growth was enhanced only when coexisted with alder. Our results suggested that a highly productive or keystone plant species in a community had greater influence over soil functions than the contribution of diversity.

Introduction of the rice CYP714D1 gene into Populus inhibits expression of its homologous genes and promotes growth, biomass production and xylem fibre length in transgenic trees.

The rice (Oryza sativa) OsCYP714D1 gene (also known as EUI) encodes a cytochrome P450 monooxygenase which functions as a gibberellin (GA)-deactivating enzyme, catalysing 16α, 17-epoxidation of non-13-hydroxylated GAs. To understand whether it would also reduce the production of active GAs and depress the growth rate in transgenic trees, we constitutively expressed OsCYP714D1 in the aspen hybrid clone Populus alba×P. berolinensis. Unexpectedly, ectopic expression of OsCYP714D1 in aspen positively regulated the biosynthesis of GAs, including the active GA1 and GA4, leading to promotion of the growth rate and biomass production in transgenic plants. Transgenic lines which showed significant expression of the introduced OsCYP714D1 gene accumulated a higher GA level and produced more numerous and longer xylem fibres than did the wild-type plants. Quantitative real-time PCR indicated that transcription of most homologous PtCYP714 genes was suppressed in these transgenic lines. Therefore, the promoted GA and biomass production in transgenic trees constitutively expressing OsCYP714D1 is probably attributed to the down-regulated expression of the native PtCYP714 homologues involved in the GA biosynthesis pathway, although their precise functions are yet to be further elucidated.

Cinnamate 4-Hydroxylase (C4H) genes from Leucaena leucocephala: a pulp yielding leguminous tree.

Leucaena leucocephala is a leguminous tree species accounting for one-fourth of raw material supplied to paper and pulp industry in India. Cinnamate 4-Hydroxylase (C4H, EC 1.14.13.11) is the second gene of phenylpropanoid pathway and a member of cytochrome P450 family. There is currently intense interest to alter or modify lignin content of L. leucocephala. Three highly similar C4H alleles of LlC4H1 gene were isolated and characterized. The alleles shared more than 98 % sequence identity at amino acid level to each other. Binding of partial promoter of another C4H gene LlC4H2, to varying amounts of crude nuclear proteins isolated from leaf and stem tissues of L. leucocephala formed two loose and one strong complex, respectively, suggesting that the abundance of proteins that bind with the partial C4H promoter is higher in stem tissue than in leaf tissue. Quantitative Real Time PCR study suggested that among tissues of same age, root tissues had highest level of C4H transcripts. Maximum transcript level was observed in 30 day old root tissue. Among the tissues investigated, C4H activity was highest in 60 day old root tissues. Tissue specific quantitative comparison of lignin from developing seedling stage to 1 year old tree stage indicated that Klason lignin increased in tissues with age.

Cloning and characterization of a ß-amyrin synthase gene from the medicinal tree Aralia elata (Araliaceae).

Aralia elata is an important medicinal plant in China; it produces large amounts of oleanane type triterpene saponins. A full-length cDNA encoding ß-amyrin synthase (designated as AeAS) was isolated from young leaves of A. elata by reverse transcription-PCR. The full-length cDNA of AeAS was found to have a 2292-bp open reading frame, encoding a protein with 763 amino acid residues. The deduced amino acid sequence of AeAS showed the highest identity (97%) to Panax ginseng ß-amyrin synthase. When AeAS cDNA was expressed in Escherichia coli, an 87.8-kDa recombinant protein was detected by SDS-PAGE and Western blotting. The sequence was also heterologously expressed in the yeast Pichia pastoris, and production of ß-amyrin was detected by HPLC. Tissue expression pattern analysis by real-time reverse transcription-PCR revealed that AeAS is strongly expressed in leaves and stems, and weakly expressed in roots and flowers.

Determination of the proportion of total soil extracellular acid phosphomonoesterase (E.C. 3.1.3.2) activity represented by roots in the soil of different forest ecosystems.

The aim of this study is to present a new method for determining the root-derived extracellular acid phosphomonoesterase (EAPM) activity fraction within the total EAPM activity of soil. EAPM activity was determined for roots, organic and mineral soil. Samples were collected using paired PVC cylinders, inserted to a depth of 15 cm, within seven selected forest stands. Root-derived EAPM formed between 4 and18% of the total EAPM activity of soil from forests of differing maturity. A new approach, presented in this work, enables separation of root-derived EAPM activity from total soil EAPM. Separation of root-derived EAPM from soil provides a better understanding of its role in P-cycling in terrestrial ecosystems. The method presented in this work is a first step towards the separation of root- and microbe-derived EAPM in soils, which are thought to possess different kinetic properties and different sensitivity to environmental change.

Identification of a homolog of Arabidopsis DSP4 (SEX4) in chestnut: its induction and accumulation in stem amyloplasts during winter or in response to the cold.

Oligosaccharide synthesis is an important cryoprotection strategy used by woody plants during winter dormancy. At the onset of autumn, starch stored in the stem and buds is broken down in response to the shorter days and lower temperatures resulting in the buildup of oligosaccharides. Given that the enzyme DSP4 is necessary for diurnal starch degradation in Arabidopsis leaves, this study was designed to address the role of DSP4 in this seasonal process in Castanea sativa Mill. The expression pattern of the CsDSP4 gene in cells of the chestnut stem was found to parallel starch catabolism. In this organ, DSP4 protein levels started to rise at the start of autumn and elevated levels persisted until the onset of spring. In addition, exposure of chestnut plantlets to 4 °C induced the expression of the CsDSP4 gene. In dormant trees or cold-stressed plantlets, the CsDSP4 protein was immunolocalized both in the amyloplast stroma and nucleus of stem cells, whereas in the conditions of vegetative growth, immunofluorescence was only detected in the nucleus. The studies indicate a potential role for DSP4 in starch degradation and cold acclimation following low temperature exposure during activity-dormancy transition.

Impact of endochitinase-transformed white spruce on soil fungal communities under greenhouse conditions.

Chitinase genes isolated from plants, bacteria or fungi have been widely used in genetic engineering to enhance the resistance of crops and trees to fungal pathogens. However, there are concerns about the possible effect of chitinase-transformed plants on nontarget fungi. This study aimed at evaluating the impact of endochitinase-transformed white spruce on soil fungal communities. Endochitinase-expressing white spruce and untransformed controls were transplanted in soils from two natural forests and grown for 8 months in a greenhouse. Soil fungal biomass and diversity, estimated through species richness and Shannon and Rao diversity indices, were not different between transgenic and control tree rhizospheres. The fungal phylogenetic community structure was the same in soil samples from control and transgenic white spruces after 8 months. Soil type and presence of seedlings had a much more significant impact on fungal community structure than the insertion and expression of the ech42 transgene within the white spruce genome. The results suggest that the insertion and constitutive expression of the ech42 gene in white spruce did not significantly affect soil fungal biomass, diversity and community structure.

Season- and age-associated telomerase activity in Ginkgo biloba L.

Telomeres have lately received considerable attention in the development of broad-leaved tree species. In order to determine tissue-, sex-, season- and age-specific changes in telomerase activity in ginkgo trees, analyses of the telomerase repeat amplification protocol were carried out. In all of the tissues detected (embryonal callus, microspore tissues and leaves) telomerase activity was found, with differences between these activities statistically significant (P < 0.05). The highest telomerase activity was found in embryonal callus, suggesting that ginkgo trees have tissue-specific telomerase activity. Tissues containing high levels of dividing cells also have high levels of telomerase activity. No significant difference of telomerase activity was found between male and female trees (P > 0.05). In the annual development cycle, the highest telomerase activity was found in April and a decreasing trend over time in the four age groups studied: 10, 20, 70 and 700 year. The most obvious decline appeared in trees of the 700 year old group, suggesting that ginkgo trees have season-specific telomerase activities and trees of various ages react differently to seasonal changes. The mean annual telomerase activity showed a regular decreasing trend in all leaf samples analyzed from 10 to 700 year old ginkgo trees. We conclude that maintenance of telomere length depends on season- and age- associated telomerase activity. An optimal telomere length is regulated and maintained by telomerase in Ginkgo biloba L.

Ecology of coarse wood decomposition by the saprotrophic fungus Fomes fomentarius.

Saprotrophic wood-inhabiting basidiomycetes are the most important decomposers of lignin and cellulose in dead wood and as such they attracted considerable attention. The aims of this work were to quantify the activity and spatial distribution of extracellular enzymes in coarse wood colonised by the white-rot basidiomycete Fomes fomentarius and in adjacent fruitbodies of the fungus and to analyse the diversity of the fungal and bacterial community in a fungus-colonised wood and its potential effect on enzyme production by F. fomentarius. Fungus-colonised wood and fruitbodies were collected in low management intensity forests in the Czech Republic. There were significant differences in enzyme production by F. fomentarius between Betula pendula and Fagus sylvatica wood, the activity of cellulose and xylan-degrading enzymes was significantly higher in beech wood than in birch wood. Spatial analysis of a sample B. pendula log segment proved that F. fomentarius was the single fungal representative found in the log. There was a high level of spatial variability in the amount of fungal biomass detected, but no effects on enzyme activities were observed. Samples from the fruiting body showed high ß-glucosidase and chitinase activities compared to wood samples. Significantly higher levels of xylanase and cellobiohydrolase were found in samples located near the fruitbody (proximal), and higher laccase and Mn-peroxidase activities were found in the distal ones. The microbial community in wood was dominated by the fungus (fungal to bacterial DNA ratio of 62-111). Bacterial abundance composition was lower in proximal than distal parts of wood by a factor of 24. These results show a significant level of spatial heterogeneity in coarse wood. One of the explanations may be the successive colonization of wood by the fungus: due to differential enzyme production, the rates of biodegradation of coarse wood are also spatially inhomogeneous.