Relationship between basidiospore size,shape and life history characteristics: a comparison of polypores

Although spore dispersal is the predominant mode of spread in fungi, the functional ecology of offspring (spore) size and shape has received little attention. We investigated the relationship between spore size (volume) and shape and various life history parameters among 303 European polypore species. In an analysis of variance, basidiocarp size, nutritional mode (parasitic vs. saprotrophic) and host (conifer vs. deciduous) accounted for a significant part of the variation in spore size. Species producing large basidiocarps also produce large spores, parasites produce larger spores than saprotrophs, and species colonizing deciduous trees generally produce larger spores than those colonizing conifers. There was a correlation between spore size and shape, with larger spores being more spherical. The most important factors accounting for variation in spore shape were rot type (white rot vs. brown rot) and nutritional mode, with white rot species and parasites having more spherical spores compared to brown rotters and saprotrophs.     

丽江老君山国家公园木腐真菌区系组成与分布特征

木腐真菌是自然界中以木材为主要生长基质的一类大型真菌,通过分解倒死木的木质素、纤维素和半纤维素实现森林生态系统的物质循环,是森林生态系统的重要组成部分。研究木腐真菌的生态分布及其与环境因子的关系对分析其在森林生态系统中的生态功能有重要作用。本文在野外调查的基础上对云南省丽江老君山国家公园的木腐真菌物种组成和生态习性进行了分析,共采集标本196份,经鉴定为68种,隶属于8目21科40属,优势科为多孔菌科、拟层孔菌科和锈革孔菌科,优势属为异担子菌属,其区系组成以北温带成分为最多(38.2%),其次是世界广布成分,表现出明显的北温带特征。从生态习性来看,63种为腐生菌,其中51种造成白色腐朽,12种造成褐色腐朽;5种为外生菌根菌。木腐真菌的物种组成在不同林分中存在明显差异,落叶阔叶林中种类最多,共34种;其次为针阔混交林,有26种;暗针叶林有22种。脆波斯特孔菌与粗毛韧革菌在3种林分类型中均有分布且多度较高,是该地区的优势种。     

中国木本植物病原木材腐朽菌研究

简要论述了中国木本植物致病木材腐朽菌,报道危害活立木的木腐菌152种,其中49种（占总数的34%）在中国首次报道为林木病原菌。对每个种的寄主、侵染部位、腐朽类型、发生频率及分布进行了报道。它们中有135种（占总数的89%）造成木材白色腐朽,17种导致褐色腐朽;67种为常见种,33种为偶见种,52种为少见种。     

大兴安岭林区多孔菌的区系组成与种群结构

本文在过去10 a野外调查和室内鉴定及分析研究的基础上,对大兴安岭林区多孔菌的区系组成和种群结构进行了分析,发现大兴安岭林区的多孔菌具有较高的多样性,共有5目11科56属129种,占中国多孔菌区系的21.36%,优势科是多孔菌科。种的区系地理成分分为7类,以北温带成分和世界广布成分为主,具有明显的北温带成分的区系特征。大兴安岭的多孔菌常见种较多,种群结构中共生菌3种,寄生菌27种,腐生菌占大多数,有99种。在能够引起木材腐朽的126种真菌中,白腐菌93种,占多数,褐腐菌33种,占少数,但该地区褐腐菌所占比例明显高于全国范围内褐腐菌在多孔菌中的比例。通过对大兴安岭主要树种上的种群结构进行比较,表明阔叶树上的木材腐朽菌绝大部分是白色腐朽菌,而针叶树上的白腐菌与褐腐菌数量相差不大,褐腐菌对于针叶林特别是落叶松的更新具有非常重要的作用。     

Temperature effects on hyphal growth of wood-decay basidiomycetes isolated from Pinus densiflora deadwood

Hyphal growth rates were tested on malt extract agar plates at eight different temperatures (5–40?°C) using 36 isolates of 17 basidiomycete species obtained from Pinus densiflora deadwood in Japan. All isolates of four brown rot species showed optimum growth at 30?°C, whereas the optimum growth temperature of white rot species varied from 20?°C to 30?°C. Analysis using a dataset from four cooler sites showed that brown rot fungi grew more rapidly than white rot fungi at higher temperatures (25?°C, 30?°C, and 35?°C). These results suggest that the hyphal growth of brown rot fungi might be physiologically adapted to higher temperatures than those of white rot fungi among the fungal species inhabiting deadwood of P. densiflora in Japan.     

Description of the xylobiont larvae and pupae of the genus <Emphasis Type="Italic">Achyrolimonia</Emphasis> (Diptera,Limoniidae)

The larva and pupa of Achyrolimonia basispina (Alex.) are described for the first time. New data on the morphology of the larva and pupa of A. decemmaculata (Loew) are discussed, and the morphological characteristics of the genus are defined more exactly. The larvae of these species develop in the dead wood of deciduous trees and in the old carpophores of wood fungi.     

Species associations during the succession of wood-inhabiting fungal communities

We studied fungal succession in decaying wood by compiling time-series data of fruit body observations. We tested the hypothesis that the presence of a primary species affects the probability of a succeeding species occurring later on the same log. Significant associations were detected for 15 species pairs; these were consistent with earlier findings on co-occurrence patterns in single time surveys. We used enrichment analysis to test if species with particular life-history attributes were more often associated with the occurrence of a succeeding species, or vice versa. White rot fungi and fungi abundant as mycelia were more often associated with the occurrence of succeeding species, compared to brown rot fungi and species with low mycelial abundance. Our results indicate that certain primary species cause priority effects and non-random co-occurrence patterns in the field. These successional patterns are likely to be connected both with substrate modification and species interactions.     

Wood decay under the microscope

Many aspects of the interactions between host wood structure and fungal activity can be revealed by high resolution light microscopy, and this technique has provided much of the information discussed here. A wide range of different types of decay can result from permutations of host species, fungal species and conditions within wood. Within this spectrum, three main types are commonly recognised: brown rot, white rot and soft rot. The present review explores parts of the range of variation that each of these encompasses and emphasizes that degradation modes appear to reflect a co-evolutionary adaptation of decay fungi to different wood species or the lignin composition within more primitive and advanced wood cell types. One objective of this review is to provide evidence that the terms brown rot, white rot and soft rot may not be obsolete, but rigid definitions for fungi that are placed into these categories may be less appropriate than thought previously. Detailed knowledge of decomposition processes does not only aid prognosis of decay development in living trees for hazard assessment but also allows the identification of wood decay fungi that can be used for biotechnology processes in the wood industry. In contrast to bacteria or commercial enzymes, hyphae can completely ramify through solid wood. In this review evidence is provided that wood decay fungi can effectively induce permeability changes in gymnospermous heartwood or can be applied to facilitate the identification of tree rings in diffuse porous wood of angiosperms. The specificity of their enzymes and the mild conditions under which degradation proceeds is partly detrimental for trees, but also make wood decay fungi potentially efficient biotechnological tools.     

Fungal wood decomposer activities influence community structures of myxomycetes and bryophytes on coarse woody debris

Dead wood is an important habitat for forest organisms, and wood decay fungi are the principal agents determining the dead wood properties that influence the communities of organisms inhabiting dead wood. In this study, we investigated the effects of wood decomposer fungi on the communities of myxomycetes and bryophytes inhabiting decayed logs. On 196 pine logs, 72 species of fungi, 34 species and seven varieties of myxomycetes, and 16 species of bryophytes were identified. Although white rot was the dominant decay type in sapwood and heartwood, brown and soft rots were also prevalent, particularly in sapwood. Moreover, white rot and soft rot were positively and brown rot negatively correlated with wood pH. Ordination analyses clearly showed a succession of cryptogam species during log decomposition and showed significant correlations of communities with the pH, water content, and decay type of wood. These analyses indicate that fungal wood decomposer activities strongly influence the cryptogam communities on dead wood.     

木材腐朽菌在森林生态系统中的功能

木材腐朽菌是森林生态系统的重要组成部分,在森林生态系统中起着极为重要的降解还原作用,主要包括担子菌门非褶菌目、子囊菌门盘菌纲和半知菌类的部分真菌,能全部或部分降解木材中的木质素、纤维素和半纤维素,其降解机制有3种：白色腐朽、褐色腐朽和软腐朽．木材腐朽菌与生态系统中其它生物关系密切,为很多昆虫、鸟类提供营养,有些昆虫也能使木腐菌得到传播．保护木材腐朽菌的生物多样性是保护森林生态系统、维护生态系统健康的重要因素．     

Significant levels of extracellular reactive oxygen species produced by brown rot basidiomycetes on cellulose

It is often proposed that brown rot basidiomycetes use extracellular reactive oxygen species (ROS) to accomplish the initial depolymerization of cellulose in wood, but little evidence has been presented to show that the fungi produce these oxidants in physiologically relevant quantities. We used [(14)C]phenethyl polyacrylate as a radical trap to estimate extracellular ROS production by two brown rot fungi, Gloeophyllum trabeum and Postia placenta, that were degrading cellulose. Both fungi oxidized aromatic rings on the trap to give monohydroxylated and more polar products in significant yields. All of the cultures contained 2,5-dimethoxyhydroquinone, a fungal metabolite that has been shown to drive Fenton chemistry in vitro. These results show that extracellular ROS occur at significant levels in cellulose colonized by brown rot fungi, and suggest that hydroquinone-driven ROS production may contribute to decay by diverse brown rot species.     

Epidemiology of Maize Root Rot in South Africa

Maize roots were rapidly infected by soil inhabiting fungi as soon as they differentiated. The first tissues to develop were the seminal roots and mesocotyls. As their function became superseded by that of the adventitious roots, they rapidly became, completely rotted. Adventitious root rot developed slower and the roots did not become as severely rotted. Numerous fungi were isolated from the roots. The most frequently isolated were Helminthosporium pedicellatum and Fusarium moniliforme. Trichoderma sp. was the next most frequently isolated fungus; it was, however, significantly less frequently isolated than the above. Young and Kucharek (1977) found that the fungi isolated from maize roots occur in communities associated with certain plant growth stages. This was not clearly evident in this study. Numbers of root lesion nematodes (Pratylenchus species) correlated non-significantly with fungus frequencies and root rot.     

Differences in crystalline cellulose modification due to degradation by brown and white rot fungi

Wood-decaying basidiomycetes are some of the most effective bioconverters of lignocellulose in nature, however the way they alter wood crystalline cellulose on a molecular level is still not well understood. To address this, we examined and compared changes in wood undergoing decay by two species of brown rot fungi, Gloeophyllum trabeum and Meruliporia incrassata, and two species of white rot fungi, Irpex lacteus and Pycnoporus sanguineus, using X-ray diffraction (XRD) and ¹³C solid-state nuclear magnetic resonance (NMR) spectroscopy. The overall percent crystallinity in wood undergoing decay by M. incrassata, G. trabeum, and I. lacteus appeared to decrease according to the stage of decay, while in wood decayed by P. sanguineus the crystallinity was found to increase during some stages of degradation. This result is suggested to be potentially due to the different decay strategies employed by these fungi. The average spacing between the 200 cellulose crystal planes was significantly decreased in wood degraded by brown rot, whereas changes observed in wood degraded by the two white rot fungi examined varied according to the selectivity for lignin. The conclusions were supported by a quantitative analysis of the structural components in the wood before and during decay confirming the distinct differences observed for brown and white rot fungi. The results from this study were consistent with differences in degradation methods previously reported among fungal species, specifically more non-enzymatic degradation in brown rot versus more enzymatic degradation in white rot.     

Substrate affinities of wood decay fungi are foremost structured by wood properties not climate

Wood decomposing fungi differ in their substrate affinities, but to what extent factors like wood properties influence host specialization, compared to climate, is largely unknown. In this study, we analysed British field observations of 61 common wood decay species associated with 41 tree and shrub genera. While white rot fungi ranged from low-to high-substrate affinity, brown rot fungi were exclusively mid-to high-affinity. White rot fungi associated with dead fallen wood demonstrated the least substrate affinity. The composition of wood decomposer fungi was mostly structured by substrate properties, sorted between angiosperms and conifers. Any relationships with temporal and regional climate variability were of far less significance, but did predict community-based and substrate-usage host shifts, especially for fungi on fallen deadwood. Our results demonstrate that substrate shifts by wood-decay fungi will depend primarily upon their degree of affinity to, and the distribution of, related woody genera, followed less at regional levels by climate impacts.     

大兴安岭林区火烧迹地木腐菌主要类群的初步研究

对大兴安岭林区火烧迹地的17种主要木腐菌进行了报道,并就它们的生态习性和生态功能进行探讨．通过对火烧林分和非过火林分主要木腐菌类群变化的研究,确定在火烧迹地森林生态系统演替过程中的先锋菌物主要有8种,常见菌4种,以及在寒温带针叶林生态系统中的珍稀和濒危的木腐菌3种,并探讨了珍稀或濒危菌物的保护对策．     

中国濒危的多孔菌

1992-2009年在全国范围内对中国多孔菌进行了系统调查,基于对多孔菌生境是否受到威胁,初步将48种中国多孔菌列为濒危种,占中国多孔菌总数的8%;分布于20个省和自治区,其中绝大部分生长于原始森林中,主要在倒木和腐朽木上;它们几乎不能在人为干扰的林分内生存;38种为木材白色腐朽菌,9种为褐色腐朽菌,1种为树木菌根菌。对每种的基本形态学、生长基质和生态习性进行了简要论述。     

Wood-decay type and fungal guild dominance across a North American log transplant experiment

We incubated 196 large-diameter aspen (Populus tremuloides), birch (Betula papyrifera), and pine (Pinus taeda) logs on the FACE Wood Decomposition Experiment encompassing eight climatically-distinct forest sites in the United States. We sampled dead wood from these large-diameter logs after 2 to 6 y of decomposition and determined wood rot type as a continuous variable using the lignin loss/density loss ratio (L/D) and assessed wood-rotting fungal guilds using high-throughput amplicon sequencing (HTAS) of the ITS-2 marker. We found L/D values in line with a white rot dominance in all three tree species, with pine having lower L/D values than aspen and birch. Based on HTAS data, white rot fungi were the most abundant and diverse wood-rotting fungal guild, and soft rot fungi were more abundant and diverse than brown rot fungi in logs with low L/D values. For aspen and birch logs, decay type was related to the wood density at sampling. For the pine logs, decay type was associated with the balance between white and brown/soft rot fungi abundance and OTU richness. Our results demonstrate that decay type is governed by biotic and abiotic factors, which vary by tree species.     

Ligninolytic and Nonligninolytic Mineralization of Trinitrotoluene by Several White Rot Basidiomycetes

The explosive 2,4,6-trinitrotoluene (TNT) is considered a toxic environmental pollutant that contaminates the soil and ground water. The white rot fungus Phanerochaete chrysosporium is well known for the degradation of TNT under ligninolytic condition. Very few, if any, studies have been done using other white rot fungi. In this study four fungal species, namely, P. chrysosporium, Kuehneromyces mutabilis, Hypholoma fasciculare, and Phlebia radiata, were used to investigate TNT degradation. All fungi were grown under ligninolytic (low-nitrogen) and nonligninolytic (high-nitrogen) conditions containing 25 parts per million (ppm) (0.11 mM) of TNT. Analysis by high-performance liquid chromatography (HPLC) showed biotransformation of TNT under both conditions. Complete degradation occurred under ligninolytic conditions (peroxidase enzymes were present) by P. chrysosporium and P. radiata. A nitrite release assay at 6 days indicated the denitrifying abilities of all the tested varieties of white rot fungi. For both ligninolytic and non-ligninolytic conditions, mass-balance studies showed biotransformation of 0.5 μ Ci ¹⁴C-labeled TNT with pregrown mycelial pellets of all fungal species, in which 5% to 15% of the TNT was converted to CO₂. These studies show that TNT may be degraded by several other species of white rot fungi and provided additional information on the biodegradation of nitroaromatic compounds in the environment.     

On the ecology of fungal consortia of spring sap-flows

Spring sap-flow, i.e. xylem sap exuding through wounds of deciduous trees in spring, quickly becomes colonised by yeasts and filamentous fungi, of which several species occur regularly in consortia from different trees or regions. This article considers the survival, spread and population dynamics of these fungi, with particular emphasis on the substantial research by Wladyslav I. Golubev on birch sap-flows in Russia. Most fungi survive in the soil or epiphytically on tree trunks, and dispersal between trees is probably mediated by insects. Competition within and between sap-flow yeast species may be due to nutritional effects or the action of killer toxins (mycocins).     

A Comparison between the Cellulolytic Activity of White and Brown Rot Fungi. I. The Activity on Insoluble Cellulose

About 70 strains of white and brown rot fungi were cultivated on media, containing filter paper cellulose as the main carbon source. The cellulolytic activity of the culture filtrates was measured after different periods of growth by means of the turbidimetric method. The results obtained indicate a difference between the two types of wood decay fungi as to the capacity of attacking the cellulose used in the medium and in the cellulase test. No significant C₁activity was found in any of the brown rot cultures whereas all white rot fungi tested exerted a measurable activity on the test substrate. The effect of various carbohydrates and some proteins as inducers of cellulase activity was studied. Especially cellobiose and lactose were active on white rot fungi in this respect, particularly in the presence of yeast extract. Also some brown rot fungi exerted C₁-activity after incubation on glucose or cellobiose.