Anatomical studies on ectomycorrhizas

Ectomycorrhizas of 5-month-old Pinus patula plants grown in autoclaved shola soil (forest soil) inoculated with basidiospores of Amanita muscaria, Laccaria laccata and Suillus brevipes are described. The main em phasis is on the organisation of the mantle tissue as seen in plan view and features of associated hyphae and strands. The different layers in the mantle produced by the different fungi are described and illustrated.     

Development and function of Pisolithus and Scleroderma ectomycorrhizas formed in vivo with Allocasuarina,Casuarina and Eucalyptus

The effect of inoculating seedlings of Eucalyptus grandis, Allocasuarina littoralis and Casuarina equisetifolia with two isolates of Pisolithus and two isolates of Scleroderma from under eucalypts was examined in a glasshouse trial. Ectomycorrhizas formed extensively on Eucalyptus (23–46% fine roots ectomycorrhizal) and Allocasuarina (18–51% fine roots ectomycorrhizal). On Casuarina, the fungi were either unable to colonize the rhizosphere (one isolate of Pisolithus), or sheathed roots, resembling ectomycorrhizas, formed on 1–2% of the fine roots. Colonization of roots by one isolate of Scleroderma resulted in the death of Casuarina seedlings. Inoculation with fungi increased shoot dry weight by up to a factor of 32 (Eucalyptus), 4 (Allocasuarina) and 3 (Casuarina). Ectomycorrhizas formed in associations with Eucalyptus and Allocasuarina had fully differentiated mantles and Hartig nets in which the host and fungal cells were linked by an extensive fibrillar matrix. Sheathed roots in Casuarina lacked a Hartig net, and the epidermis showed a hypersensitive reaction resulting in wall thickening and cell death. The sheaths are described as mantles since the density and arrangement of the hyphae in the sheaths was similar to that in mantles of the eucalypt ectomycorrhizas. The intercellular carbohydrate matrix was not produced in the Casuarina mantle in association with Pisolithus, hence the mantle was not cemented to the root. These structures differ from poorly compatible associations described previously for Pisolithus and Eucalyptus. The anatomical data indicate that ectomycorrhizal assessment based on surface morphological features may be misleading in ecological studies because compatible and incompatible associations may not be distinguishable.     

Ectomycorrhizae formed in vitro by quaking aspen: including Inocybe lacera and Amanita pantherina

Ectomycorrhizae formed in synthesis tubes by aspen (Populus tremuloides) seedlings and each of seven fungal isolates are described. Isolates of Amanita muscaria v. formosa, A. pantherina, Inocybe lacera, and Paxillus vernalis, from sporocarps collected in aspen stands in southwestern Montana, developed mantles and Hartig nets on aspen roots, as did the broad-hostrange fungi Cenococcum geophilum and Pisolithus tinctorius from the VPI culture collection. Chalciporus piperatus failed to form mycorrhizae, and Piloderma croceum formed a mantle, but no Hartig net. The first syntheses of I. lacera and A. pantherina with aspen are reported.     

Comparative studies on ectomycorrhizae synthesized with various in vitro techniques using Picea abies and two Hebeloma species

Summary Various in vitro synthesis techniques with Picea abies and two Hebeloma species showed that structures of the mantle and Hartig net of synthesized ectomycorrhizae within the given two fungus species are stable. However, thickness of mantle, and penetration depth and number of hyphal cell rows between cortical cells of the Hartig net are dependent on techniques and substrates. Porous glass balls as substrate in the Erlenmeyer technique seem to suppress or delay mantle and Hartig net formation. With the other techniques (growth pouch, open cuvette, Erlenmeyer with a vermiculite-peat moss mixture) development of the mantle is simultaneous with or shortly in advance of Hartig net formation. The ectomycorrhizae of the two tested Hebeloma species are similar and cannot be morphologically differentiated by the in vitro techniques used.     

Comparative structural study ofQuercus serrata andQ. acutissima formed byPisolithus tinctorius andHebeloma cylindrosporum

Ectomycorrhizas were synthesized in pots and growth pouches betweenQuercus serrata, Q. acutissima, and two ectomycorrhizal fungi,Pisolithus tinctorius andHebeloma cylindrosporum. Root morphology and the structure of the mantle and Hartig net were compared using light, fluorescence, scanning and transmission electron microscopy.P. tinctorius initially colonized root cap cells, and eventually produced a highly branched lateral root system with a complete mantle, whereasH. cylindrosporum promoted root elongation with few hyphae on the root apex surface indicating that interaction between roots differs with fungal species. Hartig net structure and hyphal inclusions varied between all the combinations tested. There were structural differences between mycorrhizas ofH. cylindrosporum/Q. acutissima grown in soil and growth pouches, which indicate that the growth pouch environment can induce artefacts in roots. Fruit bodies ofH. cylindrosporum developed in pots withQ. acutissima. AlthoughP. tinctorius has been used to inoculate oak seedlings in the nursery, results of this study indicate thatH. cylindrosporum may also be an effective ectomycorrhizal fungus forQ. serrata andQ. acutissima.     

Mycorrhiza of the host-specific Lactarius deterrimus on the roots of Picea abies and Arctostaphylos uva-ursi

The ectomycorrhizal basidiomycete species Lactarius deterrimus Gröger is considered to be a strictly host-specific mycobiont of Picea abies (L.) Karst. However, we identified arbutoid mycorrhiza formed by this fungus on the roots of Arctostaphylos uva-ursi (L.) Spreng. in a mixed stand at the alpine timberline; typical ectomycorrhiza of P. abies were found in close relation. A. uva-ursi is known as an extremely unspecific phytobiont. The mycorrhizae of both associations are described and compared morphologically. The mycorrhiza formed by L. deterrimus on both A. uva-ursi and P. abies show typical ectomycorrhizal features such as a hyphal mantle and a Hartig net. The main difference between the mycorrhizal symbioses with the different phytobionts is the occurrence of intracellular hyphae in the epidermal cells of A. uva-ursi. This emphasizes the importance of the plant partner for mycorrhizal anatomy. This is the first report of a previously considered host-specific ectomycorrhizal fungus in association with A. uva-ursi under natural conditions. The advantages of this loose specificity between the fungus and plant species is discussed.     

青霉属的三个新种

本文报导青霉属的三个新种,它们不同于此属已发表的诸种.异型青霉(Penicillium heteromorphum Kong et Qi),根据帚状枝的结构和分生孢子的某些特征,近于两型孢青霉(Penicillium dimorphosporum Swart),但此种在查氏琼脂上生长很稀疏,并有两种大小的分生孢子,大分生孢子直径可达10 pm,壁光滑,在观察菌落期间,有时大分生孢子落在基质上,很快萌发生长成简单的分生孢子结构,这些特征易于与后者区分.结节青霉(Penicillium nodulum Kong et Qi)在某些方面类似纠缠青霉(Penicilliumimplicatum Biourge),此新种的菌落特征,柄顶端膨大似顶囊,呈结节状膨大的营养菌丝等特征而不同于纠缠青霉.神农架青霉(Penicillium shennong jianum Kong et Qi)和毡毛青霉(Penicillium velutinum van Heyma)相近,而新种在多种培养基上生长都局限,菌落面呈带褐的橄榄色,分生孢子壁光滑等特征可与毡毛青霉区分开来.     

Polish Glomales

Spores of Acaulospora dilatata and Scutellospora dipurpurascens found in Poland are described and illustrated and their occurrence and distribution are characterized and mapped. Spores of Acaulospora dilatata from Poland do not differ from those originally described in the United States of America. The germination shield found in a number of spores is described and illustrated, and compared with that occurring in members of the genus Scutellospora. Acaulospora dilatata was found in five of the 303 soil samples taken from around the roots of Ammophila arenaria colonizing maritime sand dunes of the Sowinski National Park. Polish specimens of S. dipurpurascens are similar in size, wall structure, and reaction in Melzer's reagent to those described from the type localized in the United States of America. However, some spores from Poland have a thicker wall, greater sporogenous cells, and are somewhat darker coloured. They were recovered from 34 soils sampled from forests, gardens, sand dunes, and both cultivated and uncultivated soils. S. dipurpurascens was commonly associated with different plants of the Hel Peninsula and occurred regularly among the roots of Ammophila arenaria growing in the Slowinski National Park. Both species were found for the first time in Poland and are probably new to Europe.     

Indonesian Kickxellales: two species of <Emphasis Type="Italic">Coemansia</Emphasis> and <Emphasis Type="Italic">Linderina</Emphasis>

Four species belonging to Kickxellales (Kickxellomycotina) isolated from soil of Indonesia are described and illustrated. Two new species of Coemansia, C. asiatica and C. javaensis, were discovered in South Sulawesi and West Java, and two known species of Linderina, L. pennispora and L. macrospora, were discovered in East Kalimantan and South Sulawesi, respectively. These four species are newly added to the Indonesian mycobiota. A technique for inducing sporulation of C. javaensis and L. macrospora by adding substances derived from invertebrates such as aphids, nereids, or cladocerans to culture media is described.     

New and interesting species ofNeosartorya from Brazilian soil

Neosartorya udagawae, a new heterothallic species isolated from Brazilian soil, is described and illustrated. It is characterized by dull green colony on malt extract agar, light yellow large ascomata, broadly lenticular ascospores with two equatorial or several irregular crests and tuberculate convex surfaces, and with anAspergillus anamorph.Neosartorya aureola is also described as a new record from Brazilian soil.     

New and interesting species ofEmericella from Chinese soil

Emericella miyajii, a new species isolated from Chinese soil, is described and illustrated. It is characterized by pale orange to brownish orange colonies on malt extract agar, subglobose to broadly elliptical ascospores with defective four equatorial crests and smooth convex walls, and with anAspergillus anamorph.Emericella undulata is also described as an uncommon species from Chinese soil.     

Biodiversity of soil-inhabiting fungi

This survey is concerned only with filamentous fungi living in the soil layer. The observed diversity of soil fungi largely depends on the method used and the numbers of isolates obtained. Particle-plating usually yields higher numbers of taxa than dilution plating. The Centraalbureau voor Schimmelcultures (CBS) preserves a great diversity of soil fungi. The CBS database contained 2,210 species of soil fungi in 2001, an estimated 70% of the known species available in culture. Thus, the current estimate for described culturable soil fungi is approximately 3,150 species, many of which have a cosmopolitan distribution. Adding the ca. 150 spp. of nonculturable Glomerales results in 3,300 species of currently known soil fungi. Molecular studies in such groups as Fusarium, Trichoderma, Penicillium, and Aspergillus are finding a number of more narrowly distributed cryptic species. Thus the number of species of soil fungi is expected to be considerably higher than the 3300 species currently known.     

Materials for the fungus flora of Japan (49)

Two interesting microfungi are described as new to Japan:Talaromyces galapagensis (anam.Penicillium galapagense), isolated from soil in Shizuoka; andPenicillium megasporum, isolated from marine sludge in Nagasaki. Some observations are recorded, particularly on ascomatal initials ofT. galapagensis, which are similar to those described forTalaromyces flavus.(48): Kaneko, S., Mycoscience 36: 359–360, 1995.     

Ectomycorrhizas of Cortinarius helodes and Gyrodon monticola with Alnus acuminata from Argentina

Field ectomycorrhizas of Cortinarius helodes Moser, Matheny & Daniele (sp. nov) and Gyrodon monticola Sing. on Alnus acuminata Kunth (Andean alder, aliso del cerro) are described based on morphological and anatomical features. Ectomycorrhizal roots were sampled beneath fruitbodies of C. helodes and G. monticola from two homogeneous A. acuminata forest sites located in Tucumán and Catamarca Provinces in Argentina. C. helodes ectomycorrhizas showed a thick white to beige mantle exuding a milky juice when injured, were bluish toward the apex, and had hyphal strands in the mantle. G. monticola ectomycorrhizas showed some conspicuous features like highly differentiated rhizomorphs, inflated brown cells on the mantle surface, and hyaline and brown emanating hyphae with dolipores. Restriction fragment length polymorphism analysis of the nuclear rDNA internal transcribed spacer provided a distinctive profile for each of the collections of fruitbodies and the mycorrhizal morphotypes.     

Phytophthora quercetorum sp. nov., a novel species isolated from eastern and north-central USA oak forest soils

Isolates belonging to an undescribed Phytophthora species were frequently recovered during an oak forest soil survey of Phytophthora species in eastern and north-central USA in 2004. The species was isolated using an oak leaf baiting method from rhizosphere soil samples collected from Quercus rubra, Q. macrocarpa, and Q. phellos. This species is formally described as P. quercetorum. It is homothallic and has aplerotic oogonia and paragynous antheridia. It produces papillate sporangia (occasionally bipapillate) of ovoid-elongated shapes. Its temperature optimum for growth is ca 22.5 °C with the upper limit of ca 32.5 °C. P. quercetorum differs from the morphologically related P. quercina in producing distinct submerged colony-patterns, different growth-temperature requirements, and oogonial shapes and sizes. Phylogenetic analyses using seven nuclear loci supported P. quercetorum as a novel species within clade 4, closely related to P. arecae, P. palmivora, P. megakarya, and P. quercina.     

Detection and quantification of Entomophaga maimaiga resting spores in forest soil using real-time PCR

Environmental sampling to monitor entomopathogen titre in forest soil, a known reservoir of insect pathogens such as fungi and viruses, is important in the evaluation of conditions that could trigger epizootics and in the development of strategies for insect pest management. Molecular or PCR-based analysis of environmental samples provides a sensitive method for strain- or species-based detection, and real-time PCR, in particular, allows quantification of the organism of interest. In this study we developed a DNA extraction method and a real-time PCR assay for detection and quantification of Entomophaga maimaiga (Zygomycetes: Entomophthorales), a fungal pathogen of the gypsy moth, in the organic layer of forest soil. DNA from fungal resting spores (azygospores) in soil was extracted using a detergent and bead mill homogenization treatment followed by purification of the crude DNA extract using Sephadex–polyvinylpolypyrrolidone microcolumns. The purification step eliminated most of the environmental contaminants commonly co-extracted with genomic DNA from soil samples but detection assays still required the addition of bovine serum albumin to relieve PCR inhibition. The real-time PCR assay used primers and probe based on sequence analysis of the nuclear ribosomal ITS region of several E. maimaiga and two E. aulicae strains. Comparison of threshold cycle values from different soil samples spiked with E. maimaiga DNA showed that soil background DNA and remaining co-extracted contaminants are critical factors determining detection sensitivity. Based on our results from comparisons of resting spore titres among different forest soils, estimates were best for organic soils with comparatively high densities of resting spores.     

Materials for the fungus flora of Japan (53)

Two interesting ascomycetes are described as new to Japan:Ascotricha amesii (Xylariaceae), isolated from garden soil in Osaka; andAuxarthron reticulatum, isolated from forest soil in Tokyo. ADicyma anamorph is associated with the former species. (52): Tubaki, K., Tokumasu, S. and Konno, M., Nippon Kingakukai Kaiho38: 249–250. 1997.     

Fennellia flavipes andNeosartorya stramenia,two new records from Japan

Two interesting species of cleistothecial Ascomycetes withAspergillus anamorphs are described:Fennellia flavipes andNeosartorya stramenia. Both species were isolated from soil smaples collected in 1992 as a new record to Japan.     

Application of 15N natural abundance technique for evaluating biological nitrogen fixation in oil palm ecotypes at nursery stage in pot experiments and at mature plantation sites

A range of different species of diazotrophic bacteria has been found in tissues and the rhizosphere of oil palm plants, suggesting a potential to benefit from biological nitrogen fixation (BNF). A few studies have confirmed that plantlets at nursery stage can benefit significantly from BNF after inoculation with Azospirillum spp. but no data are available regarding the benefit from naturally-occurring diazotrophic bacteria in oil palm. The results described here were derived from two pot trials laid out under controlled conditions with plantlets from two important regions for palm oil production in Brazil, as well as from different field sites of mature oil palm plantations. The ¹⁵N natural abundance technique was employed to estimate plant dependence on BNF (%Ndfa) by the different ecotypes grown in soil and previously characterized as hosting diazotrophic bacteria. From both pot trials it was possible to identify some ecotypes of high potential for N₂-fixation that reached in some cases approximately 50%Ndfa. However, the accuracy of measurement still needs to be improved using more suitable reference plants for pot experiments. Values of δ ¹⁵N signals from oil palm and reference plants in the field were inconclusive concerning any benefit from BNF to oil palm, owing to apparently high temporal and spatial variability of δ ¹⁵N of the plant-available N in the heterogeneous soil matrix for the different palm and reference plant tested.