Phylloplane microfungal metabolite influences activity of RuBisCO

The phylloplane microbes are known to affect systemic acquired resistance in plants against a broad spectrum of pathogens. The influence of phylloplane microbes and their metabolites on physiology and biochemistry of plants is well-documented but their effect on the physiology and functioning of chloroplasts and mitochondria is not well understood. The present study was conducted to understand the impact of metabolite of a dominant phylloplane microfungi (Fusarium oxysporum) isolated from the phylloplane of Lycopersicon esculentum on activity of RuBisCO. Activity of RuBisCO (EC 4.1.1.39) in chloroplasts of fungal metabolite treated and untreated eight-week old tomato plants were studied. Significant increase in the activity of RuBisCO (P???0.01), isolated from plants inoculated with the fungal metabolite was observed. The fungal metabolite could elicit the enzyme activity by about two folds (P???0.05) within 72–96?h of treatment of tomato plants. The result demonstrates that probably phylloplane microfungi and/or their metabolites influence the photosynthetic efficiency of plants.     

Pioneer forays for fungi in the Darién Province in Eastern Panama: quintuplicating the knowledge on fungi in this area by five days of fieldwork

For the Darién Province, an area larger than Jamaica in Eastern Panama, up to now only 19 species of fungi, mainly lichens and plant parasitic microfungi, have been known. Two general mycological forays including most major groups of fungi were carried out in this area for the first time. During 3 days mostly in secondary vegetation and 2 days in pristine forest, about 104 specimens of macro- and microfungi were collected, of which 85 were identified as 76 species of which all but one were new records for the Darién Province. As a result, knowledge on fungal taxa in that region has risen from 19 to 94, i.e. by a factor of five. Although common and easily-spotted species were preferred during collection, 16 (more than 20%) of the species identified were new for Panama, notably two species of Agaricales, Hygroaster nodulisporus and Leucopaxillus gracillimus, and four microfungi on plants, Cercosporella leucaenae, Coccomyces delta, Meliola bixae, and Stigmina anacardii. The records of the species are presented together with specimen data, references, and photos of selected species. As shown by this study, fungi in tropical Panama are highly diverse, mostly unknown, and further mycological field work is urgently needed because habitats are destroyed and fungi specific to them are lost forever.     

Succession of microfungal assemblages in decomposing peatland plants

We investigated the microfungal assemblages in the decomposing tissues of dominant plant species in two peatlands in southern boreal Alberta, Canada, to determine if distinct patterns of succession of microfungi occurred throughout the first two years of decomposition. These plant species were Sphagnum fuscum from a bog and Carex aquatilis leaves and rhizomes and Salix planifolia leaves and roots from a riverine, sedge-dominated fen. Canonical correspondence analyses, a multivariate statistical analysis used infrequently in mycological research, revealed distinct patterns of fungal species succession in two of the five litters (S. fuscum and C. aquatilis leaves). Furthermore, our analyses showed that substantially different microfungal assemblages were associated with these litters within the first two years of decomposition. Litter quality variables, such as total nitrogen, total phosphorus, and total carbon tissue nutrient concentrations, explained most of the succession patterns and differences in the microfungal assemblages of these five litters. Our data did not reveal the classical taxonomic zygomycete – ascomycete/fungi imperfecti – basidiomycete pattern of succession during organic matter decomposition. Similarly, a succession of functional groups of microfungi, i.e., cellulose-degraders preceding lignin-degraders, generally was not apparent. Instead, microfungi with broad spectra of enzymatic abilities co-existed over the first two years of decomposition in these peatland plant litters. These microfungi have a limited ability to decompose complex phenolic polymers, such as lignin, resulting in the accumulation of peat in these ecosystems. Some microfungal taxa were not affected by changes in litter quality, environmental variables, or surface water chemistry and were present at all stages of decomposition.     

Broad spectrum management of plant diseases by phylloplane microfungal metabolites

Plant surfaces are colonised by an array of microbes. These microbes have been implicated in protecting plants against invading pathogens. Studies have demonstrated that metabolites of phylloplane microfungi can induce defence responses in their host plants. This investigation relates to formulation of a biocide from metabolites of Aspergillus niger, Trichoderma viride, Alternaria alternata and Chaetomium globossum, which are common phylloplane colonisers of tropical plants. The biocide was found to reduce disease incidence through induction of alterations in defence physiology of crop plants.     

Yeasts and moulds contaminants of food ice cubes and their survival in different drinks

Aims

To evaluate the levels of unicellular and filamentous fungi in ice cubes produced at different levels and to determine their survival in alcoholic beverages and soft drinks.

Methods and Results

Sixty samples of ice cubes collected from home level (HL) productions, bars and pubs (BP) and industrial manufacturing plants (MP) were investigated for the presence and cell density of yeasts and moulds. Moulds were detected in almost all samples, while yeasts developed from the majority of HL and MP samples. Representative colonies of microfungi were subjected to phenotypic and genotypic characterization. The identification was carried out by restriction fragment length polymorphism (RFLP) analysis of the region spanning the internal transcribed spacers (ITS1 and ITS2) and the 5·8S rRNA gene. The process of yeast identification was concluded by sequencing the D1/D2 region of the 26S rRNA gene. The fungal biodiversity associated with food ice was represented by nine yeast and nine mould species. Strains belonging to Candida parapsilosis and Cryptococcus curvatus, both opportunistic human pathogens, and Penicillium glabrum, an ubiquitous mould in the ice samples analysed, were selected to evaluate the effectiveness of the ice cubes to transfer pathogenic microfungi to consumers, after addition to alcoholic beverages and soft drinks. All strains retained their viability.

Conclusions

The survival test indicated that the most common mode of consumption of ice cubes, through its direct addition to drinks and beverages, did not reduce the viability of microfungi.

Significance and Impact of the Study

This study evidenced the presence of microfungi in food ice and ascertained their survival in soft drinks and alcoholic beverages.     

Microfungal diversity associated with Kindbergia oregana in successional forests of British Columbia

Species richness and species composition of microfungi associated with Oregon beaked moss (Kindbergia oregana) were studied at two forest chronosequences on southeast Vancouver Island, British Columbia, Canada. The purposes were to investigate the effects of clear-cutting and the transformation of old-growth forests into secondary forests on microfungi and the succession of microfungi in relation to long-term stand development. Green and brown parts of moss were collected from the forest floor of Douglas-fir (Pseudotsuga menziesii) stands of four age classes: post-harvest regeneration (13–14 years), immature (50–51 years), and mature (85–101 years) stands, and a control old-growth (296–324 years) stand, and used for the isolation of microfungi. A total of 49 microfungal species were recorded. Study site, stand age, and moss parts significantly affected the species richness and species composition of microfungi. The species richness of microfungi was significantly greater on brown than on green moss parts and lower in post-harvest regenerations than in forest stands of the other age classes. The species composition of major microfungal species changed gradually along the seral stages. Possible environmental and biological factors that could account for the succession of microfungi were discussed.     

Primo contributo alla micoecologia della lettiera di lentisco in alcune isole minori della Sardegna meridionale

Abstract

Preliminary account of the microfungi colonizing Pistaca lentiscus L. litter - A preliminary account of the microfungi colonizing Pistacia lentiscus L. leaf litter in five small islands of South Sardinia is carried out. Two species, Beltrania rhombica Penzig and Endophragmiella boewei (Crane) Hughes are present in almost all the samples investigated. A very low index in richness of species seems to be characteristic of this particular area.     

Air spore microfungi in dwellings of south of Spain

Summary Indoor and outdoor airborne microfungi were studied in fourteen homes of Córdoba (Spain) for two years. Samplings were done gravimetrically in three rooms in each home and, for comparison, also outdoors. An overall 128 taxa were identified, which were classified according to their occurrence into occasional, frequent and permanent. No statistically significant quantitative differences were found between the microfungi in each room. On the other hand, there were significant quantitative differences between indoor and outdoor microfungi. Spores occurred at their maximum concentrations in spring. Finally,Aspergillus andCladosporium were found to be the most abundant genera indoors and outdoors, respectively.     

Molecular characterization of pathogenic Fusarium species in cucurbit plants from Kermanshah province, Iran

Fusarium is one of the important phytopathogenic genera of microfungi causing serious losses on cucurbit plants in Kermanshah province, the largest area of cucurbits plantation in Iran. Therefore, the objectives in this study were to isolate and identify disease-causing Fusarium spp. from infected cucurbit plants, to ascertain their pathogenicity, and to determine their phylogenetic relationships. A total of 100 Fusarium isolates were obtained from diseased cucurbit plants collected from fields in different geographic regions in Kermanshah province, Iran. According to morphological characters, all isolates were identified as Fusarium oxysporum, Fusarium proliferatum, Fusarium equiseti, Fusarium semitectum and Fusarium solani. All isolates of the five Fusarium spp. were evaluated for their pathogenicity on healthy cucumber (Cucumis sativus) and honeydew melon (Cucumis melo) seedlings in the glasshouse. F. oxysporum caused damping-off in 20–35 days on both cucurbit seedlings tested. Typical stem rot symptoms were observed within 15 days after inoculation with F. solani on both seedlings. Based on the internal transcribed spacer (ITS) regions of ribosomal DNA (rDNA) restriction fragment length polymorphism (RFLP) analysis, the five Fusarium species were divided into two major groups. In particular, isolates belonging to the F. solani species complex (FSSC) were separated into two RFLP types. Grouping among Fusarium strains derived from restriction analysis was in agreement with criteria used in morphological classification. Therefore, the PCR-ITS-RFLP method provides a simple and rapid procedure for the differentiation of Fusarium strains at species level. This is the first report on identification and pathogenicity of major plant pathogenic Fusarium spp. causing root and stem rot on cucurbits in Iran.     

Soil Saprotrophic Microfungi Associated with Roots of Calamagrostis epigeios on an Abandoned Deposit of Toxic Waste from Smelter Factory Processing Pyrite Raw Materials

Saprotrophic microfungi associated with roots of Calamagrostis epigeios growing in industrial waste contaminated with high concentrations of heavy metals (manganese, iron, zinc) were isolated on three different media. The isolates were obtained from three plots colonized by plant cenoses, representing three different succession series of plant cover: initial, intermediate, and advanced. A total of 60 species of saprotrophic microfungi were found in the roots during three samplings. In addition, unidentified dark and white sterile mycelia were frequently isolated. Trichoderma koningii was frequent in the roots formed under the advanced phytocenose. The abundance of dark sterile mycelium gradually decreased with progressing succession of the plant cover. Chrysosporium merdarium was rarely observed in the roots under the intermediate and advanced plant cenoses. Multivariate redundancy analysis showed that the effect of succession stage of phytocenoses on incidence of saprotrophic microfungi in mycocenoses present in roots was statistically significant. When the similarity of root mycocenoses of the three plots was studied using the similarity coefficients, the results proved that the similarities between the initial and intermediate or intermediate and advanced mycocenoses were higher than that between the initial and advanced mycocenoses. This corresponds to a different speed of succession of the mycocenoses. The results suggest that the dark sterile mycelia, abundant at slowly developing plots, play a dominant role during the first stages of succession where the plant cover is poor.     

Contributions mycologiques pour la connaissance de la spermatosphère des graines en germination

Summary A list of 26 species of microfungi found on seeds of various plants is presented. A new genus of Hypocreaceous Ascomycete is describedViennotidia, which includes two different species. Moreover, the following species are described as new:Phoma cuscutae, Sclerophomina tritici, Sirophoma petroselini andPyrenochaeta spinaciae.     

Soil Microfungi in Two Post-Mining Chronosequences with Different Vegetation Types

Soil microfungi were studied in the Sokolov (Czech Republic) post‐mining dumps afforested with Alnus glutinosa and in the Lusatian (Germany) post‐mining dumps afforested with Pinus sylvestris or P. nigra. Microfungi were isolated using the soil dilution plate method. Soil microfungi communities of two chronosequences were compared by species composition, frequency of species occurrence, and colony forming units of fungi (CFU‐counts). Differences in species occurrence were determined. More species of entomopathogenic microfungi were found from the Sokolov post‐mining area in comparison with the Cottbus post‐mining area. Absidia glauca, A. cylindrospora, Penicillium glabrum, and P. janthinellum were the most frequently isolated species from the Cottbus post‐mining area, while A. glauca, Geomyces pannorum, and Trichoderma koningii predominated at the Sokolov post‐mining area.     

Taxonomic studies on new or critical fungi of non-pathogenic Onygenales 1

From recent isolates of microfungi on soil materials collected at several localities in the world, five new taxa of the Onygenales are described and illustrated. A new monotypic genus,Kraurogymnocarpa lenticulospora, is proposed. New species are described inAmauroascus, Aphanoascus, andArachnomyces. A new variety ofPseudogymnoascus roseus is also proposed.     

A study of fungi found in association with Histoplasma capsulatum: three bird roosts in S.E. Missouri,U.S.A.

Summary Soil samples from three bird roosts in SE Missouri were studied in an effort to detect differences in the distribution of microfungi in sites contaminated withHistoplasma capsulatum and presumably favorable, but uncontaminated sites. Seventy-four of 151 species identified were found in conjunction withH. capsulatum; many of the remaining 77 species were isolated only rarely and are probably not important colonizers of these soils. Only minor differences were noted regarding distribution of more commonly occurring species. Fungi known to be parasitic or antagonistic to other microfungi were about evenly distributed among the sites.H. capsulatum was most abundant in the one roost which was still occupied by flocks of birds.     

Vertical Divergence of Cultured Microfungal Communities at the Hallamish Dune Field,Western Negev Desert,Israel

We examined the depthwise distribution of microfungi through 0–40 cm of sandy profiles under bare surface and different shrub species at the Nizzana research site (NRS) in the Negev Desert, Israel. A total of 125 species from 61 genera were isolated using the soil dilution plate method. At the topsoil of all profiles melanin-containing species with large multicellular conidia predominated. In the middle depths at the majority of the profiles, mesic group of microfungi, Penicillium spp. substantially increased in abundance. Density of microfungal isolates decreased with depth under shrubs and did not substantially vary in the nonshaded profiles, highly positively correlating with electrical conductivity and organic matter (OM) content. Substantial increase in isolate densities at the undercanopy habitats, especially in the interdune depression with higher substrate stability raising the accumulation of OM, highlights the role of shrubs as “islands of fertility” for microfungal communities at NRS.     

Interactions Between Testate Amoebae and Saprotrophic Microfungi in a Scots Pine Litter Microcosm

In all terrestrial ecosystems, testate amoebae (TA) encounter fungi. There are strong indications that both groups engage in multiple interactions, including mycophagy and decomposition of TA shells, processes which might be fundamental in nutrient cycling in certain ecosystems. Here, we present the results of an experiment focusing on interactions between TA and saprotrophic microfungi colonizing Scots pine (Pinus sylvestris L.) litter needles. The needles were collected from a temperate pine forest and cultivated in damp chambers. Over a few weeks, melanized mycelium of Anavirga laxa Sutton started to grow out of some needles; simultaneously, the common forest-soil TA Phryganella acropodia (Hertwig and Lesser) Hopkinson reproduced and spread around the mycelium. We investigated whether a potential relationship between TA and saprotrophic microfungi exists by comparing the composition of TA communities on and around the needles and testing the spatial relationship between the A. laxa mycelium and P. acropodia shells in the experimental microcosm. Additionally, we asked whether P. acropodia utilized the A. laxa mycelium as a nutrient source and screened whether P. acropodia shells were colonized by the microfungi inhabiting the experimental microcosm. Our results indicate that saprotrophic microfungi may affect the composition of TA communities and their mycelium may affect distribution of TA individuals in pine litter. Our observations suggest that P. acropodia did not graze directly on A. laxa mycelium, but rather fed on its exudates or bacteria associated with the exudates. The fungus Pochonia bulbillosa (Gams & Malla) Zare & Gams was often found parasitising encysted shells or decomposing already dead individuals of P. acropodia. TA and pine litter microfungi engage in various direct and indirect interactions which are still poorly understood and deserve further investigation. Their elucidation will improve our knowledge on fundamental processes influencing coexistence of soil microflora and microfauna.     

Contribution to the fungus flora of Rhum: Microfungi on pines

Summary

A list of fifty five species of microfungi collected on needles, twigs and cones of pines from Rhum (Hebrides, Scotland) is presented. Of these, Sporonema diamandidis and Xylohypha ortmansiae are published as new species, and Rosellinia obliquata is reported as new to the British list. A further thirty three species are new to the Rhum list. Five of the new or interesting species are described, four illustrated, and the unusual status of Lophodermium seditiosum on the island is briefly noted.     

Beech log decomposition by wood-inhabiting fungi in a cool temperate forest floor: a quantitative analysis focused on the decay activity of a dominant basidiomycete <Emphasis Type="Italic">Omphalotus guepiniformis</Emphasis>

Wood decay activity of Omphalotus guepiniformis, one of the most frequently occurring fruiting bodies on beech coarse woody debris in cool temperate forests in Japan, was estimated in situ by chronosequence with a five decay class system. The decay columns of O. guepiniformis increased from decay class 1 to decay class 2, where they occupied 20.2% of the total area of cross sections, and was estimated to be a dominant basidiomycete. The decay columns of O. guepiniformis decreased after decay class 2 and were not detected in decay class 5. The relative density of the decay columns of O. guepiniformis decreased to 0.33 g cm⁻³ in decay class 2 (58.9% of fresh beech wood) but did not decrease thereafter. The lignocellulose index (LCI) of the decay columns of O. guepiniformis slightly decreased during the decay process while remaining in the range of white-rot. In contrast, the decay columns of microfungi increased in the later stages of decomposition and LCI of these decay columns decreased significantly alongside the decay process. These results suggest that O. guepiniformis has an important role in simultaneous decomposition of acid-unhydrolyzable residue (AUR, Klason lignin) and holocellulose in the early stages of beech log decomposition, while holocellulose selective decomposition by microfungi may occur in the late stages of decomposition.     

Saprobic microfungi under Lolium perenne and Trifolium repens at different fertilization intensities and elevated atmospheric CO2 concentration

Anthropogenic increases in atmospheric CO₂ concentration and the connected deposition of organic matter into the soil influence the occurrence of decomposers who regulate carbon release back into the atmosphere. The effects of increased concentration of atmospheric carbon dioxide, plant species cover quality and nitrogen (N) fertilization on the coenosis composition of soil saprobic microfungi were studied under field conditions (Swiss Free Air Carbon Dioxide Enrichment experiment). In total, 42 species of microfungi were detected in examined soil. The most significant response of soil mycoflora was induced by the species identity of plant cover. Higher N fertilization significantly suppressed the abundance of soil microfungi at ambient CO₂. The effect of increased CO₂ on colony‐forming units was not significant when taken as an independent treatment; however, this factor interacted significantly with N availability. Some species, e.g. the Clonostachys rosea, were proven associated with the plant cover components, in this particular case with Trifolium repens. Therefore, we suggest the identity of plant species constituting plant cover as the most important factors affecting soil microfungi in agroecosystems.     

The effect of temperature on the growth ofCandida saké isolated from the leaves of a subantarctic grass

During a survey of microfungi on the subantarctic island of South Georgia, large numbers of phylloplane yeasts were isolated in late spring from leaves of a tussock grass. The dominant yeast was identified asCandida saké, this being the first record for the Antarctic region. Isolates in liquid culture had a temperature optimum for growth of 20–25°C. It was capable of assimilation of a range of simple carbohydrates, similar to those found in leachates from new leaves of the tussock grass. The seasonal decline of yeasts on the phylloplane is discussed in terms of the availability of leachate and the growth of filamentous microfungi on new leaves.