Sterile Fungus Research Articles

The identification of Mycelium radicis atrovirens (Phialocephala dimorphospora)

Mycelium radicis atrovirens is known as a sterile fungus colonizing the surface of rootlets of trees in the boreal forest. Microscopic examination of 41 isolates conforming in vegetative morphology to the type description of this fungus revealed the presence of phialoconidia corresponding to Phialocephala dimorphospora in 15.

Fungal diseases of cotton plant <i>Gossypium hirsutum</i> L. in Bangladesh

Seven types of symptom were recorded in four varieties such as CB3, CB9, Hill cotton 1 (HC-1) and 2 (HC-2) of cotton (Gossypium hirsutum L.) during July, 2005 to June, 2008. The symptoms were Anthracnose, Alternnaria leaf spot, Boll rot, Cercospora leaf spot, Rust, Sclerotium rot and Wilting. Present study revealed that association of 30 species of fungi which belonged to 21 genera such as one one in Zygomycetes, one in Ascomycetes, one in Basidiomycetes, 18 in Deutermycetes and one in sterile fungus. The isolated fungi were Alternaria alternata (Fr.) Keissler, Arthrinium sp., Ascochyta sp., Aspergillus flavus, Link., Aspergillus niger Van Tiegh, Aspergillus sp., Botryodiplodia sp., Cercospora sp., Chaetomium sp., Chaetophoma sp., Cladosporium sp., Colletotrichun coffeanum Noack, z. f. Pflan zenko., Colletotrichum spp., Curvularia clavate Jain, Curvularia lunata (Wakker) Boedijn, Fusarium moniliforme, Wr. and Reink, Fusarium spp., Nigrospora sp., Pestalotia sp., Penicillium sp., Phoma sp., Pteroconium sp., Puccinia sp., Rhizopus stolonifer (Ehrenb. Ex. Fr) Lind, Sclerotium rolfsii Sacc., Trichoderma viride Pers. ex Fries. and one sterile fungus. Fusarium spp. and Colletotrichum spp. were frequently associated with all the four cotton varieties examined. Botryodiplodia sp. was associated with Hill Cotton 1 (HC-1) and Hill Cotton 2 (HC-2). Sclerotium rolfsii was found associated with CB-3 cotton variety. Key words: Fungal diseases; Cotton plant; Gossypium hirsutum; Bangladesh DOI: http://dx.doi.org/10.3329/dujbs.v20i2.8974 DUJBS 2011; 20(2): 139-146

Litter decomposing fungi in sal (Shorea robusta) forests of central India

Abstract. Soni KK, Pyasi A, Verma RK. 2011. Litter decomposing fungi in sal (Shorea robusta) forests of central India. Nusantara Bioscience 3: 136-144. The present study aim on isolation and identification of fungi associated with decomposition of litter of sal forest in central India. Season-wise successional changes in litter mycoflora were determined for four main seasons of the year namely, March-May, June-August, September-November and December-February. Fungi like Aspergillus flavus, A. niger and Rhizopus stolonifer were associated with litter decomposition throughout the year, while Aspergillus fumigatus, Cladosporium cladosporioides, C. oxysporum, Curvularia indica, and C. lunata were recorded in three seasons. Some fungi including ectomycorrhiza forming occur only in the rainy season (June-August) these are Astraeus hygrometricus, Boletus fallax, Calvatia elata, Colletotrichum dematium, Corticium rolfsii, Mycena roseus, Periconia minutissima, Russula emetica, Scleroderma bovista, S. geaster, S. verrucosum, Scopulariopsis alba and four sterile fungi. Fungi like Alternaria citri, Gleocladium virens, Helicosporium phragmitis, and Pithomyces chartarum were rarely recorded only in one season.

Nuclear Distribution in Vegetative Cells of Ophiobolus Graminis and other Cereal Root Pathogens

Difficulty is 'sometimes experienced in distinguishing between O. graminis and sterile fungi which form "Ophiobolus-like" runner hyphae on cereal roots. However, it is possible that nuclear distribution in mycelium may prove a differential character as different distributions have already been reported for O. graminis (Chambers and Flentje 1967) and a cereal root-attacking strain of Rhizoctonia solani (Flentje, Stretton, and Hawn 1963). This paper, therefore, describes comparisons of nuclear distribution in O. graminis and several other cereal root pathogens including a sterile fungus which formed Ophiobolus-like runner hyphae.

The Effects of Some Soil-Borne Fungi On the Sex Ratio of Heterodera Rostochiensis On Tomato

The sex ratio of Heterodera rostochiensis on tomato was increased not only by high larval population density, but also by the presence of the three plant pathogenic fungi: Rhizoctonia solani, Verticillium alboatrum and grey sterile fungus. The sex ratio of H. rostochiensis increased with an increase in the fungus inoculum.

Effects of cultural treatments on the incidence of, and damage done by, tomato brown root rot

SUMMARYIn soils naturally infested with Pyrenochaeta lycopersici, which usually occurs as a grey sterile fungus (GSF), symptoms of brown root rot (BRR) developed sooner and more extensively in the second year of cropping than in the first. The amount of BRR attributable to corkiness increased as plants aged but, at comparable stages of cropping, decreased in the second and third seasons, an effect associated inversely with the severity of early GSF attack. The larger amount of corkiness, 33 compared with 18 %, on two batches of plants in 1965, each with 53 % end‐of‐season BRR, was also attributed to a less severe early GSF attack on the former than on the latter, growing in soils unsteamed for 1 and 3 years respectively.The incidence of BRR decreased with increasing depth in infested soils but increased on plants grown in plots with partially sterilized topsoil.Partially sterilizing soils at the G.C.R.I. and Fairfield E.H.S. decreased the incidence of BRR and increased crop weights from about the second month of picking, but fruit quality was poorer. Seasonal yields from plants in untreated soil progressively decreased relatively to those from repeatedly steamed plots, from 93 to 65 % in successive years at Fairfield and from 65 to 56 and 43 % at the G.C.R.I. Steaming done in 1963 and 1964 temporarily retarded GSF attack in 1965 with corresponding yield increases.Increasing the amounts of sterilized propagating soil surrounding roots at planting from 0·4 to 1·01 per plant increased yields by c. 0·4 kg/plant, this being a relatively large increase for plants in infested soil, where this treatment significantly delayed the early incidence of BRR near stem bases.Grafting commercially acceptable scions to rootstocks that tolerated colonization by GSF (‘resistant’ rootstocks), temporarily checked growth, delayed picking and decreased fruit quality. Usually grafted plants, irrespective of soil treatment, yielded at least as much fruit as ungrafted plants in steamed soil. In one of five comparisons, soil steaming increased yields of grafted plants. When testing the effects of previous cropping it seemed that populations of GSF increased similarly in soils planted with grafted and ungrafted plants.In addition to GSF attack, roots at Fairfield E.H.S. were often colonized by Colletotrichum coccodes, microsclerotia (= black dots) being more numerous as plants aged. Although significantly more black dot developed on GSF‐resistant rootstocks grown in untreated soil than on those grown in steamed soil, the differences were not associated with effects on yield. C. coccodes colonized GSF‐susceptible and ‐resistant roots equally.

The formation of giant cells in tomato roots infected by the potato cyst nematode, Heterodera rostochiensis and the grey sterile fungus, G.S.F

The formation of giant cells in tomato roots infected by the potato cyst nematode, Heterodera rostochiensis and the grey sterile fungus, G.S.F

Methyl Bromide Fumigation of Soil Infested by the Fungus Causing Brown Root Rot Complex of Tomatoes and by the Potato Cyst Nematode

SUMMARYIn glasshouse soils infested with grey sterile fungus, the cause of brown root rot of tomato, and the potato cyst nematode, methyl bromide fumigation increased yield, and controlled the nematode at all except the lowest treatment applied. In the experiments described here methyl bromide did not affect the development of brown root rot.

Lysis of the cell walls of yeast ( Saccharomyces cerevisiae) by soil fungi

Two fungi, Fusarium sp. and an unidentified sterile fungus (no. 6), have been isolated from soil and their lytic activity towards cell walls of yeast (Saccharo-myces cerevisiae) examined. Growth of the two fungi on solid and liquid media containing autoclaved whole yeast or yeast cell walls resulted in lysis of the cell walls in both instances. Filtrates from cultures of both fungi grown on autoclaved walls, or whole yeast, showed glucanase activity when this was estimated with laminarin as substrate and this activity was greatest at pH 5·0. The cell walls of preheated whole yeast lost much of their opacity (phase-contrast microscopy) when incubated, in the presence of 2-mercaptoethanol at pH 5·0 and 7·5, with the culture filtrate from the sterile fungus no. 6. Isolated walls (unheated) were also incubated in a similar manner and chemical analysis showed that the walls had lost 77% (at pH 5·0) and 65% (at pH 7·5) of their anthrone-positive constituents after 6 days at 30 °C; the walls lost much of their opacity when incubated at pH 7·5 only. In the absence of 2-mercaptoethanol the losses amounted to 37% at pH 5·0 and 25% at pH 7·5. Ultra-thin sections of whole yeast and shadowed preparations of isolated cell walls examined in the electron microscope provided important information on the manner in which these materials were degraded.

Effect of the Causal Fungus of Brown Root Rot of Tomatoes on the Hatch of the Potato Root Eelworm, Heterodera rostochiensis Woll

RECENT observations on the brown root rot complex of tomatoes caused Last and Ebben1 to support the view of Termohlen2 that a fungus which produces a grey sterile mycelium in culture is responsible for the brown root rot symptoms. Preliminary studies on the occurrence of potato root eel worm and the grey sterile fungus (GSF) on the roots of tomato revealed that the development of the nematode is adversely influenced by the presence of the fungus. It was thought that the restriction of the reproduction of the nematode could be caused by some substance (or substances) produced by the fungus and which affect the hatch of potato root eelworm, or its subsequent migration to and development in the host plant roots. An investigation of the former is reported here.

The epidemiology of tomato brown root rot

SUMMARYIn the absence of nematodes, three different symptoms of disease, parts of the brown root rot complex (BRR), occurred on tomato roots surviving in soils infested with GSF (= grey sterile fungus) and Colletotrichum atramentarium (Berk. & Br.) Taubenh. In heavily infested soils brown lesions occurred throughout cropping, appearing within a week of planting. Corkiness and black dot, caused by GSF and C. atramentarium respectively, rarely occurred until the third month after planting but towards the end of the season the incidence of black dot sometimes suddenly increased greatly.Observations of crops growing in plots treated with different soil partial sterilants suggested that GSF was more damaging than C. atramentarium. Yield was not related to the incidence of black dot but was inversely proportional to the occurrences of brown lesions and corkiness. The relation with brown lesions was significant within 8 weeks of planting, when most brown lesions gave cultures of GSF, but later more of these lesions gave cultures of C. atramentarium than of GSF.Pathogenicity tests with pure cultures of GSF and C. atramentarium were done on agar media and by artificially infesting partially sterilized soils. Roots of undamaged seedlings on agar media developed 10 mm. brown lesions within 2 weeks of inoculating 10‐day‐old tomatoes with most GSF cultures isolated from: (1) rotted roots of Lycopersicon esculentum, Solanum capsicastrum, Capsicum annuum var. longum and C. frutescens; (2) browned zones of Lycopersicon hirsutum roots; and (3) apparently healthy roots of Cucumis sativus. After inoculation with C. atramentarium, small (c. 2 mm.) pink lesions developed, whereas none formed using Pyrenochaeta spp.In soil tests the greater root damage done by GSF, including root loss, was reflected in decreased aerial growth and smaller fruit yields; C. atramentarium affected neither. In the second year of soil infestation GSF decreased yields during 6 weeks of picking from 1.96 kg. in the uninoculated controls to 1.02 kg./plant.The pattern of damage done by GSF changed as plants aged. In soil, brown lesions occurred within a few days of planting but corkiness did not appear for 2–3 months, when stem lesions and leaf yellowing often developed simultaneously. A 50% root loss after 21 weeks did not affect fruit yields whereas a 40% loss within 11 weeks of planting was reflected by a 45% yield decrease.

Observations on the corky root disease of tomatoes in England

A sterile fungus corresponding closely in mycelial characters to that described by Canadian and Dutch workers has been isolated from tomato plants with corky root symptoms in England. About half the isolates produced micro-sclerotia in culture. In typical corky lesions, microsclerotia, confined to single cells of the host and smaller than those produced on agar, have been detected microscopically. These smaller microsclerotia from infected roots have been shown to yield the sterile grey fungus after micro-dissection and culturing on agar. Typical symptoms were produced by a microsclerotial strain of the fungus in an inoculation experiment, and the incorporation of sawdust, grass clippings and compost with the inoculum caused virtually complete suppression of disease symptoms in a small-scale experiment in the open.

Studies on fungi in the root region

By studies on selected sterile dark fungi isolated from barley roots, an attempt is made to explain the ability of these fungi to colonize young roots. Studies on growth rate in soil and competitive ability in root colonization showed these organisms to be poor competitors withFusarium oxysporum, at least as indicated by isolation studies. The value of direct observation is again emphasized, the use of this technique indicated that in competition studies sterile dark fungi were able to colonize barley roots in competition with significant populations ofFusarium oxysporum. The effects of barley root exudates on the growth of sterile dark fungi and several other soil fungi was also investigated.

Influence of fungal isolates on germination and growth of perennial ryegrass

The influence of fungi isolated from perennial ryegrass roots on the germination and development of seedlings of perennial ryegrass was investigated. The basic procedure employed was to sterilise the seed surface and then inoculate with fungi and plant in non-sterile soil. It was realised that the fungal isolate inoculated on to the sterile seed surface would not remain dominant in the root region of the host and would have an influence on the host which would decline with time from when the seed germinated. This was because it would have to face antagonism from the normal components of the root microflora present in the non-sterile soil.Trichoderma viride delayed the emergence of the seedlings and reduced the production of herbage, an observation consistent with results of some other investigators. A sterile hyaline fungus stimulated the emergence of the seedlings, but subsequent tests showed that the presence of the microflora of the seed coat, or the soil microflora, or the sterile hyaline fungus was effective in promoting the rate of germination of seed that had been surface sterilised. Leaching seed in water brought about an increase in the rate of seed germination, and it is suggested that there might be a germination inhibitor soluble in water present in the seed coat, which might be inactivated by saprophytic micro-organisms.

White root rot of raspberries.

The disease known as white root rot affects raspberries, and to a less extent loganberries, in Victoria. The causal organism is a white, sterile fungus that has not been identified. The disease is favoured by dry soil conditions and high soil temperatures. It spreads externally to the host by means of undifferentiated rhizomorphs; and requires a food base for the establishment of infection. The spread of rhizomorphs through the soil is hindered by high soil moisture content and consequent poor aeration of the soil.

Effect of partial sterilization by steam or formalin on the fungus flora of an old forest nursery soil

Treatment with steam or formalin markedly affected the fungal flora of an old forest nursery soil. The untreated nursery soil contained two soil layers, the lower of which was characterized by a very poor fungus flora. Some fifty-five species were of frequent occurrence in untreated soil, and common genera in the upper layer were Pythium, Absidia, Mortierella, Mucor, Aspergillus, Fusarium, Gliocladium, Penicillium, Phoma and Trichoderma. Both with steam or with formalin treatment, fungi were initially destroyed or reduced to very low numbers. The penetration of soil by different treatments was 16 in. for Hoddesdon steaming, 8 in. for Canopy steaming, and 5 in. for formalin treatment. Fungal recolonization of treated soil was very slow, and even 18 months after treatment numbers of species and colonies were much lower than in untreated soil. Steam-treated soil was recolonized chiefly by species of Mortierella, Phoma eupyrena and Coniothyrium sp. in the first year. These species, with Penicillium spp. and sterile fungi, were present in the second year after treatment. Recolonizing fungi were usually most abundant near the soil surface. In formalin-treated soil Trichoderma viride was the dominant recolonizer. Phoma eupyrena, Coniothyrium sp. and Fusarium spp. were also present, particularly in the second year. Fewer species recolonized formalin-treated soil than steam-treated soil. Mean height and total number of Sitka spruce seedlings grown on the experimental plots were appreciably increased by soil sterilization with steam or formalin.

Sterile Conks of Polyporus Glomeratus and Associated Cankers on Beech and Red Maple

In 1930 Hirt 1 reported sterile conks on beech (Fagus grandifolia Ehrhart.), which were associated with a normal fruiting body of Fomes Everhartii (Ellis & Gall.) Schrenk. During the summer of 1938 another type of sterile conk, with or without associated cankers, was found commonly on beech in the Green Mountain National Forest. These sterile conks, except for their smaller size, resembled those on birch recently reported by Campbell and Davidson 2 to be a sterile form of a Poria (probably Poria obliqua). Because of this resemblance and because P. obliqua or a similar Poria had been collected on beech in Pennsylvania and New Hampshire, it was originally thought that the sterile conks might be the sterile form of it. However, pure cultures of Polyporus glomeratus Peck, described by the writers,3 were isolated from the sterile conks and the associated decay. In addition, P. glomeratus fruited on down beech on which there were sterile conks and cankers. Later in the season a number of red maples (Acer rubrum Linn.) on the Gale River Experimental Forest, New Hampshire, were found to be badly cankered and decayed. Sterile fungus material characteristic of P. glomeratus was associated with the cankers and pure cultures from this material and from the decay confirmed the

A Poria as the Fruiting Stage of the Fungus Causing the Sterile Conks on Birch

The identity of the sterile fungus, so common on living birches in certain localities, and its relation to other fungi have long been disputed. It has usually been considered a sterile form of some Fomes species. Lindroth (5) and Neger (6) described sterile conks on living birches in Europe and called them abortive sporophores of Polyporus nigricans Fries. Weir (9) mentioned the occurrence of the sterile fungus and normal sporophores of Fomes igniarius (L.) Gill. on the same tree and considered the two to be the same. He found the sterile form associated with dead, sunken, canker-like areas on the trunks of living birches and suggested that moisture and freezing and thawing coupled with certain chemical substances within the wound, maintained the mycelium in a vegetative condition, thus preventing the formation of normal sporophores. Katayevskaya (4) studied F. igniarius and the sterile fungus in culture and, although she demonstrated marked differences in the appearance and in microscopic structures of the isolates from the two sources, tentatively identified the latter as a sterile form of F. igniarius. Verrall (8) in an extensive study of variation in F. igniarius concluded from a consideration of the similarity of cultures and the association of the sterile conks and normal F. igniarius sporophores on the same tree that the two were the same. Campbell (3) described the cultural characteristics of a considerable number of species of Fomes, including the sterile fungus from birch and demonstrated that cultures of this

Two New Species of Omphalia Which Cause Decline Disease in Date Palms

The species of Omphalia which constitute the subject of this paper are now considered (2) to be the cause of decline disease in the date palm, Phoenix dactylifera L. This malady was first detected in 1921 near Indio, California. Since that time the disease has become well distributed (4) throughout the date-growing region of the Indio district, but it is unknown beyond the boundaries of Riverside County. All underground parts of the palm (3) may be attacked by these fungi, but the principal injury results from the destruction of roots. Secondary symptoms (1) appear subsequently and include the premature death of leaves, retardation in the rate of terminal growth, and reduction in the size of leaves and fruitstalks. The fruit from severely affected palms is nearly worthless. Among the micro6rganisms associated with diseased palms were certain white, sterile fungi with clamp connections at the septa. The first of these cultures was isolated in 1931 by L. J. Klotz, who obtained slight evidences of infection from the inoculation of seedling date palms. Little significance was placed on these results at that time. Later work by the author (2) revealed the pathogenic nature of Klotz's culture, together with that of numerous isolates of similar character from other diseased palms. Since no fruiting bodies of these basidiomycetous fungi were found about date palms affected with decline disease, effort was directed toward inducing sporulation artificially. A group of imperfect toadstools developed in the greenhouse on a wooden pot label (FIG. 3, C). A moldy leaf base from a diseased palm had been buried in soil near the base of this marker. Mycelium which

The Texas Root Rot Fungus and Its Conidial Stage

More than twenty-five years ago Pammel ('88, '89)spent two summers in Texas investigating an important disease popularly known as the cotton blight or cotton dying, and as a result of his observations two reports were published upon the root rot,-the latter more appropriate name being applied by him to the disease in question. He determined the causal organism to be a sterile fungus found in some abundance on every dead or dying root, and it was tentatively identified as Ozonium autricomum Lk. After a study of Link's type, Shear ('07) described the organism as a new species, 0. omnivorum.