Phytotoxins produced byTubakia dryina

Tubakia dryina, the causal agent of red oak (Quercus rubra) leaf spot, produced the phytotoxins isosclerone, 3-hydroxyisosclerone, 6-hydroxyisosclerone and 6-hydroxymellein in liquid culture. All toxins caused large necrosis when placed on leaves of red oak. Necrosis was also caused on white oak and eight different weed species. All toxins were non-specific phytotoxins.     

采自栎树叶上的中国新记录属真菌—Tubakia

报道了采自辽宁省旅顺的辽东栎(Quercus liaotungensis)叶片上的椿启介菌属(Tubakia)为中国新记录属,并对该属及该属真菌干孢盾壳椿启介菌[Tubakia dryina(Sacc.)Sutton]进行了形态学描述。     

Entomopathogenic species of the hyphomycete genus Tolypocladium

Two entomopathogenic species of the hyphomycete genus Tolypocladium are described in detail. Tolypocladium extinguens sp. nov. was found on larvae of Arachnocampa luminosa (Diptera; Mycetophilidae) in caves in New Zealand. Tolypocladium cylindrosporum W. Gams is shown to be pathogenic to Aedes sierrensis and A. australis and is reported from Plecia nearctica (Diptera; Bibionidae). The occurrence of entomopathogenic species in this normally soil-borne genus is discussed.     

农业有机废物与城市生活垃圾堆肥高温期微生物种群结构比较

通过PCR、克隆文库方法分析了农业有机废物和城市垃圾堆肥高温期间细菌和真菌种群的多样性.提取堆肥高温期的DNA,PCR扩增,构建各高温期的16S rDNA和18S rDNA克隆文库,结果表明:农业有机废物和城市生活垃圾16S rDNA克隆文库中分别共有18个、21个OTUs,分别属于细菌域的14个、15个不同属,其18S rDNA克隆文库中分别共有8个、9个OTUs,分别属于细菌域的8个、9个不同属,推断农业有机废物堆体的优势菌为Bacillus megaterium、Rhizobium sp.、Phanerochaete chrysosporium、Penicillium sp.同属或同种的菌株;城市生活垃圾堆体的优势菌为Bacillus megaterium、Azospirillum sp.、Phanerochaete chrysosporium同种或同属的菌株.     

Rare lichen associations on common oak (<Emphasis Type="Italic">Quercus robur</Emphasis>) in Lithuania

The current paper presents four lichen associations, including rare and endangered lichen species found in Lithuanian oak-woods. The structure of communities on the oak, characteristic of these localities, and geographical and sociological evaluation of communities are presented. Main reasons causing the extinction of rare species in the communities are mentioned as well.     

Diversity and ecology of soil fungal communities in rubber plantations

Monoculture rubber cultivation and its intensive associated human activities are known to have a negative impact on the biodiversity, ecology, and biological conservation of the ecosystems in which they occur. These negative impacts include changes to the biodiversity and function of soil fungal communities, which contribute towards nutrient cycling and interact with other organisms in belowground ecosystems, and may be pathogens. Despite the important role of soil fungi in rubber plantations, these communities have been poorly studied. In this paper, we review the existing literature on the diversity and ecology of belowground fungi in rubber plantations. Various groups of soil fungi, including saprobes, symbionts, and pathogens are discussed. Additionally, the role of plantation management is discussed in the context of both pathogenic soil fungi and the promotion of beneficial soil fungi. Management practices include clone selection, tree age and planting density, application of chemicals, and intercropping systems. Our review shows the strong need for further research into the effects of monoculture rubber plantations on soil fungal communities, and how we can best manage these systems in the future, in order to create a more sustainable approach to rubber production.     

Interactions of Neotyphodium gansuense, Achnatherum inebrians, and plant-pathogenic fungi

Interactions of Neotyphodium gansuense, Achnatherum inebrians, and nine fungal pathogens were studied by tests of inhibition of four fungal pathogens by Neotyphodium endophytes in vitro and by inoculation of nine fungal pathogens on detached leaves of endophyte-infected (E+) and endophyte-free (E−) plants. Compared with the controls, most isolates of N. gansuense significantly inhibited the growth in vitro of, in decreasing order of inhibition, Bipolaris sorokiniana, Curvularia lunata, Fusarium acuminatum, and Alternaria alternata. Inhibition zones appeared between pathogens and some isolates of N. gansuense. Some isolates of N. gansuense significantly inhibited sporulation of B. sorokiniana, A. alternata, and C. lunata. However, there was no significant inhibition of F. acuminatum and a few isolates significantly increased sporulation. The leaf inoculation trial indicated that almost all fungal pathogens were able to cause lesions on detached leaves regardless of endophyte status. Both the number and size of disease lesions on E+ A. inebrians leaves caused by A. alternata, F. chlamydosporum, F. oxysporum, and F. solani were reduced compared with those on E− leaves. Only lesion numbers (not size) of Ascochyta leptospora leaf spots were significantly reduced on E+ leaves compared with E− leaves. Conversely, only the length of Ascochyta leptospora leaf spots were significantly smaller on E+ leaves than on E− leaves; numbers of lesions were not significantly affected. C. lunata was strongly pathogenic to both E+ and E− leaves and numerous lesions developed and merged into patches, the leaf surface was covered and the leaf rotted away.     

Occurrence of fungi in combs of fungus-growing termites (Isoptera: Termitidae, Macrotermitinae)

Fungus-growing termites cultivate their mutualistic basidiomycete Termitomyces species on a substrate called a fungal comb. Here, the Suicide Polymerase Endonuclease Restriction (SuPER) method was adapted for the first time to a fungal study to determine the entire fungal community of fungal combs and to test whether fungi other than the symbiotic cultivar interact with termite hosts. Our molecular analyses show that although active combs are dominated by Termitomyces fungi isolated with direct Polymerase Endonuclease Restriction - Denaturing Gradient Gel Electrophoresis (PCR-DGGE), they can also harbor some filamentous fungi and yeasts only revealed by SuPER PCR-DGGE. This is the first molecular evidence of the presence of non-Termitomyces species in active combs. However, because there is no evidence for a species-specific relationship between these fungi and termites, they are mere transient guests with no specialization in the symbiosis. It is however surprising to notice that termite-associated Xylaria strains were not isolated from active combs even though they are frequently retrieved when nests are abandoned by termites. This finding highlights the implication of fungus-growing termites in the regulation of fungi occurring within the combs and also suggests that they might not have any particular evolutionary-based association with Xylaria species.     

Ecological aspects of epigeous gasteromycetes (Agaricomycetes,Basidiomycota) in four remnants of the Brazilian Atlantic Forest

Species composition and richness of epigeous gasteromycetes were investigated in four remnants of the Brazilian Atlantic Forest in northeastern Brazil. Two of these areas are coastal, lowland forests, while the other two, also known as ‘brejos de altitude’, are inland, highland forests. Thirty-six field expeditions were carried out from Jun. 2008 to May 2009 in a 500 m × 20 m transect in each surveyed area. Collected specimens consisted of 16 gasteroid species of the genera Clathrus (one sp.), Cyathus (four spp.), Geastrum (nine spp.), Morganella (one sp.) and Phallus (one sp.). Analysis of Similarity (ANOSIM) showed that species richness and composition of gasteroid fungi are different between lowland and highland forests. There was no significant difference between collecting seasons (dry and rainy months) in the four localities.     

Resistance to rust fungi in Lolium perenne depends on within-species variation and performance of the host species in grasslands of different plant diversity

The hypothesis that plant species diversity and genetic variation of the host species decrease the severity of plant diseases is supported by studies of agricultural systems, but experimental evidence from more complex systems is scarce. In an experiment with grassland communities of varying species richness (1, 2, 4, 8, 16, and 60 species) and functional group richness (1, 2, 3, and 4 functional groups), we used different cultivars of Lolium perenne (perennial ryegrass) to study effects of biodiversity and cultivar identity on the occurrence and severity of foliar fungal diseases caused by Puccinia coronata (crown rust) and P. graminis (stem rust). Cultivar monocultures of perennial ryegrass revealed strong differences in pathogen susceptibility among these cultivars. Disease intensity caused by both rust fungi decreased significantly with growing species richness of species mixtures. The response to the diversity gradient was related to the decreased density and size of the host individuals with increasing species richness. The occurrence of other grass species known to be possible hosts of the pathogens in the experimental mixtures did not promote disease intensity in L. perenne, indicating that there was a high host specificity of pathogen strains. Differences in pathogen susceptibility among perennial ryegrass cultivars persisted independent of diversity treatment, host density and host individual size, but resulted in a cultivar-specific pattern of changes in pathogen infestation across the species-richness gradient. Our study provided evidence that within-species variation in pathogen susceptibility and competitive interactions of the host species with the environment, as caused by species diversity treatments, are key determinants of the occurrence and severity of fungal diseases. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.