Aspergillus niger is widely used as an enzyme source in industries. Considering its enzymic potential, A. niger was studied for its acid phosphatase (EC 3.1.3.2, orthophosphoric monoester phosphohydrolase), and invertase (EC 3.2.1.26, β-fructofuranoside fructohydrolase) activity in defined media supplemented with 1%, 3%, or 5% sucrose concentrations. Both these enzymes play a key role in phosphate and carbon metabolism in plants, animals, and microorganisms and hence are interesting from the standpoint of biotechnological applications. Ontogenic changes in extracellular, cytoplasmic, and wall-bound enzyme activities of A. niger were studied. Growth in terms of fresh weight showed inverse correlation with pH. At higher pH values, both enzyme activities were higher in the medium supplemented with low sucrose concentration. It was observed that the more the fresh weight of fungi decreased, the greater was the enzyme activity observed. It is suggested that these enzymes may participate in autolysis of fungi and, on the other hand, could prove to be a potential source of industrial application and exploitation.
We have previously isolated a target gene for the Lentinula edodes CDC5 (Le.CDC5) containing a c-Myb–type DNA-binding domain. The gene, termed ctg1, contains a 7-bp Le.CDC5-binding sequence (5′-GCAATCT3′) in its transcribed region downstream of the start codon and 6-bp CIPB-binding sequences in the 5′-upstream and transcribed regions. The expression of ctg1 appeared to be cooperatively regulated by Le.CDC5 and CIPB. Here, we found that the gene expression regulation system of ctg1–CDC5– CIPB is conserved in the basidiomycetous mushroom Coprinopsis cinerea. Similar to L. edodes, the Le.CDC5 homologue (named Cc.Cdc5) bound to a 7-bp sequence, 5′-GCAAGCT-3′, in the transcribed region of the ctg1 homologue (Cc.ctg1) and the CIPB homologue (Cc.CipB) to 6-bp sequences in its 5′-upstream and transcribed regions. To study the biological function of the Cc.ctg1 gene (and also the ctg1 gene) in C. cinerea, we bred the C. cinerea homokaryotic fruiting strains, consistently producing a large amount of the Cc.ctg1 (or ctg1) transcript. Analysis of the phenotype of these strains suggested that the Cc.ctg1 gene (or the ctg1 gene) is mainly involved in the regulation of stipe elongation.
Colonization of Salix humboldtiana (Salicaceae) by ectomycorrhizae (ECM), arbuscular mycorrhizae (AM), and dark-septate endophytic (DSE) fungi was studied throughout autumn on two riparian populations in central Argentina. AM and DSE infection on roots ranged from 0% to 17% and from 2% to 20% respectively, whereas ECM colonization was higher, varying between 33% and 99% for both sites. Seven ECM morphotypes were found on S. humboldtiana roots. The nuclear rDNA internal transcriber spacer (ITS) region from the ectomycorrhizal root tips was amplified using ITS-1F and ITS-4 primers. Two of the seven ECM types were identified by searching GenBank blasts: one attributed to the genus Tomentella (Thelephoraceae) and the second most closely matched to Inocybe sp. (Cortinariaceae). The ECM colonization varied among sampling dates and sites, whereas AM and DSE colonization varied only among sampling dates. Diversity values for the ECM morphotype were not significantly different for autumn months or among the two sites. Positive correlations were found between Inocybe sp. and sites and between Inocybe sp., Tomentella sp., morphotypes III, IV, and VI, and sampling dates. This article provides the first documented evidence of co-occurrence of ECM, AM, and DSE in S. humboldtiana.
Heterobasidion australe sp. nov. is derived from the Heterobasidion insulare complex, and its illustrated description is given. It is similar to H. ecrustosum by morphology but closely related to H. orientale genetically. Heterobasidion australe is characterized by the effused-reflexed to sessile basidiocarps with a reddish-brown crust in the pileus, shining pore surface, regular and small pores, and by slightly smaller basidiospores than those in other taxa of the complex. Heterobasidion australe has so far been recorded only from southern China, where it seems to be relatively common in coniferous forests, growing mostly on dead wood of several genera of gymnosperm trees. Occasionally it has been recorded also on living trees, but its pathogenicity is uncertain.
Three species belonging to the genus Rhytisma causing tar spot were collected on leaves in evergreen trees of Ilex species from Japan. Rhytisma ilicis-latifoliae, the known species, is found on Ilex latifolia, and R. ilicis-integrae sp. nov. and R. ilicis-pedunculosae sp. nov. are found on I. integra and I. pedunculosa, respectively. Ascomata are formed on the abaxial part of the stromata in all the Rhytisma species studied, and spermogonia are formed on the amphigenous parts in R. ilicis-latifoliae and on the adaxial part in R. ilicis-integrae and R. ilicis-pedunculosae. Shape and size of asci, ascospores, and spermatia are distinctly different among the three species. The morphology of germination tubes from ascospores and appressoria is unique for each Rhytisma species. Yellowish spots arise on the newly developing leaves in mid-May, then abundant spermatia are produced in spermogonia in the three Rhytisma species. In the next year, ascospores are produced in ascomata from early April to late May in R. ilicis-integrae and from early April to early June in R. ilicis-latifoliae and R. ilicis-pedunculosae, and they are considered to be the inocula of disease infection.
Forty-six Lecanicillium strains and one Verticillium strain were isolated from subterranean and epiphytic arthropods, soil, and other sources collected in Indonesia and Japan. These strains were identified as nine Lecanicillium and one Verticillium species including six undescribed species based on light microscopy and the sequences of the ITS-1 and ITS-2 regions including 5.8S ribosomal DNA. Four of the ten species (L. araneicola, L. kalimantanense, Lecanicillium sp. 4, and V. indonesiacum) were recovered from Indonesia, five of the ten (L. attenuatum, L. fusisporum, L. psalliotae, Lecanicillium sp. 1, and Lecanicillium sp. 3) were from Japan, and L. saksenae was from both countries. In this article, new species (L. araneicola, L. kalimantanense, and V. indonesiacum) and a new combination (L. saksenae) are proposed from the fungi isolated from epiphytic and subterranean arthropods collected in East Kalimantan.
Bicarbonates are often utilized in the food industry to avoid fermentation and to improve pH, flavor, and texture. In the same manner, bicarbonates have been demonstrated to control postharvest phytopathogens; however, there are no reports describing the effects of these chemical compounds either on soil-borne pathogens such as Sclerotinia sclerotiorum or on antagonist fungi such as Trichoderma species. This study evaluated the antifungal effect of increasing concentrations (0, 2, 4, 6, 8, 10, 25, and 50mM) of potassium bicarbonate (KHCO3) on the growth of Trichoderma sp. strain R39 and S. sclerotiorum under in vitro systems. Applications of KHCO3 greater than 8mM significantly inhibited (P<0.001) the growth of both fungi. Concentrations of KHCO3 lower than 25mM did not affect the antagonistic effect of Trichoderma on the growth of S. sclerotiorum; however, this fungal interaction was not observed when exposed to 50mM KHCO3 because of its strong inhibition of fungal growth. In addition, KHCO3 concentrations higher than 8mM caused significant (P<0.001) reduction of the sclerotium formation of S. sclerotiorum. Sclerotium germination and de novo sclerotium formation were significantly (P<0.001) inhibited as the concentrations of KHCO3 increased. Results show the potential benefits of potassium bicarbonate for controlling both growth and development of S. sclerotiorum, although it also exerts negative effects on the Trichoderma strain that is a natural antagonist to S. sclerotiorum.
We conducted line route censuses of fungal fruiting bodies from August to September in 2005 and 2006 along ridges and valleys and compared the differences in the encounter rates of fungal fruiting bodies (= fruiting bodies seen per census kilometer) between types of topography and between fungal functional groups (i.e., ectomycorrhizal and saprobic fungi) in warm temperate evergreen broad-leaved forests on Yakushima Island, Japan. We found 251 fungal fruiting bodies (26 families, 50 genera, and 65 species) in total, including 51 bodies from Tricholomataceae, 41 from Russulaceae, 25 from Boletaceae, and 19 from Amanitaceae. The encounter rate of ectomycorrhizal fungi was greater at the ridge route (26.7unit/km) than at the valley route (8.7unit/km) and that of saprobic fungi was greater at the valley route (25.0unit/km) than at the ridge route (12.5unit/km). In addition, we conducted 7-year intermittent sampling and identified 40 families, 96 genera, and 142 species. The topography-specific emergence pattern of the intermittent sampling method was similar to that of the line census method. The fungal species composition in this study was possibly affected by a topographic gradient for both fungal functional groups through soil moisture, nutrient availability, and host tree distribution.
Pilobolus crystallinus shows unique photoresponses at various growing stages. cDNAs for putative photoreceptors were cloned from this fungus. Three genes named pcmada1, pcmada2, and pcmada3 were identified from the PCR fragments, and amplified with degenerated primers for the LOV domain, which is conserved in many blue-light receptors. Deduced amino acid sequences for PCMADA1, PCMADA2, and PCMADA3 had one light-oxygen-voltage (LOV)-sensing and two PER-ARNT-SIM (PAS) domains. A zinc finger DNA-binding motif was conserved in the C-terminals of PCMADA1 and PCMADA3. However, PCMADA2 lacked the zinc finger motif. Expression of pcmada1 was suppressed by blue light whereas that of pcmada3 was promoted by blue-light irradiation