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Natural occurrence and growth of Gliodadium roseum on the mycelium and sclerotia of Botrytis allii. Trans
... Therefore, we focused our research on C. rosea. According to the literature reports, strains of this species, which are considered to be cosmopolitan, have been isolated from a wide range of soils, fungi, plant remains and plant parts (roots, leaves and even flowers), freshwater, forests, heaths, etc. (Walker and Maude, 1975;Mueller and Sinclair, 1986;Sutton et al. 1997;García et al. 2003;Nobre et al. 2005;Sun et al. 2020;Yu et al. 2020). The fungus is characterized by a variety of lifestyles, from saprobic to endophytic to parasitic, with a wide range of target organisms, including fungi, nematodes and insects (Shigo, 1958;Li et al. 2002;Verdejo-Lucas et al. 2002;Chatterton and Punja, 2012;Saraiva et al. 2015;Haarith et al. 2020;Maillard et al. 2020). ...
... Barnett and Lilly, 1962). In these works, the primary attention was paid to developing the appressorium (Makonen and Pohjakallio, 1960;Walker and Maude, 1975). Under similar conditions, the interaction with the Fusarium oxysporum was studied using C. rosea that expressed the red fluorescent protein. ...
The unfavorable phenomenon of activated sludge bulking that occurs in sewage treatment plants (WWTPs) is
caused by the over-proliferation of filamentous bacteria that should be limited by the Lecane rotifers that feed on
them; however, predatory, rotiferovorous fungi that often inhabit WWTPs pose a real threat to these organisms.
To solve this problem, we investigated the interaction of the fungus Clonostachys rosea, which is a known Biological
Control Agent (BCA) and the predacious Zoophagus sp. in simplified laboratory culture conditions. The
presence of C. rosea in the cultures reduced the number of active traps, thus translating into a much smaller
number of rotifers being caught. The mycelium of C. rosea was labeled with a red fluorescent protein (RFP). The
life cycle of C. rosea that were attacking Zoophagus sp. (hunting for rotifers) is described. C. rosea spores
germinate into single-celled forms and penetrate the interior of the Zoophagus mycelium where they feed on the
cytoplasm. Then is the mycelium produced abundantly and forms conidiophores. This type of life strategy has not
been known before. The obtained results demonstrated the potential of C. rosea as a BCA that can be used to
protect rotifers in the event of an infection of activated sludge by the predatory fungi that threaten the rotifer
population.
... Strains of C. rosea have been isolated from all continents except Antarctica and from a wide range of habitats (Sun et al., 2020a;Sutton et al., 1997), indicating a cosmopolitan distribution. Strains are typically isolated from soil, fungi, plant debris and from plant parts including roots, leaves and flowers (Walker and Maude, 1975;Nobre et al., 2005;Mueller and Sinclair, 1986;García et al., 2003), but isolations from nematodes and insects are also reported (Verdejo-Lucas et al., 2002;Haarith et al., 2020). Strains of C. rosea are even present as endophytes in several halophyte plant species in coastal areas (You et al., 2017). ...
... The attack was characterised by collapse of the surface mycelium of the fungal prey and the destruction of the dark pigment produced by some species. The attack involves attachment to the hyphae of the fungal prey and production of an appressorium, followed by penetration (Makkonen and Pohjakallio, 1960;Walker and Maude, 1975). Confocal fluorescence microscopy studies of the interaction between C. rosea expressing the green fluorescent protein and F. oxysporum forma specialis (f. ...
The fungus Clonostachys rosea was recognized as an aggressive parasite on other fungi already in the late 1950s. Research into its potential use in biological control of plant diseases soon followed. Today, there are several commercial products based on C. rosea available for biocontrol applications worldwide. Although its mycoparasitic ability has attracted a lot of interest, C. rosea is now viewed as an ecological generalist whose lifestyle also includes plant endophytism, rhizosphere competence and polyphagous ability. Protocols for producing high amounts of C. rosea spores are available for both solid state and liquid fermentation. Low temperature and low moisture content are key factors that influence the shelf life of C. rosea propagules. Products based on C. rosea can be delivered to flowers using bumble bees, applied by spraying or as seed dressing or by incorporation into the soil. Clonostachys rosea is today an established factor in sustainable plant protection strategies.
... It was reported in cultivated, grassland, woodland, forest, heathland, freshwater, and coastal soils, particularly those of neutral to alkaline pH (4,13,15,43). G. roseum is frequently associated with cysts of Heterodera spp., Globodera spp., and other nematodes in soil (6,18,24,26,36) and with sclerotia of Sclerotinia sclerotiorum, Phymatotrichum omnivorum, Rhizoctonia solani, Botrytis spp., Verticillium spp., and other fungi in soil and plant materials (25,51,61,62). Over the past 35 years, G. roseum has gained a distinctive reputation as a mycoparasite of a broad spectrum of fungi (3,30,35,37,59). ...
... This mode of action is important chiefly because it contributes to inoculum suppression of B. cinerea. G. roseum is a well-known mycoparasite of hyphae, spores, sclerotia, and fruiting bodies of numerous fungi, including B. cinerea (3,10,61). While a majority of studies were conducted on agar media, recent observations on raspberry indicated that mycoparasitism can be an important mode of biocontrol of B. cinerea on host plants (63). ...
... It was reported in cultivated, grassland, woodland, forest, heathland, freshwater, and coastal soils, particularly those of neutral to alkaline pH (4,13,15,43). G. roseum is frequently associated with cysts of Heterodera spp., Globodera spp., and other nematodes in soil (6,18,24,26,36) and with sclerotia of Sclerotinia sclerotiorum, Phymatotrichum omnivorum, Rhizoctonia solani, Botrytis spp., Verticillium spp., and other fungi in soil and plant materials (25,51,61,62). Over the past 35 years, G. roseum has gained a distinctive reputation as a mycoparasite of a broad spectrum of fungi (3,30,35,37,59). ...
... This mode of action is important chiefly because it contributes to inoculum suppression of B. cinerea. G. roseum is a well-known mycoparasite of hyphae, spores, sclerotia, and fruiting bodies of numerous fungi, including B. cinerea (3,10,61). While a majority of studies were conducted on agar media, recent observations on raspberry indicated that mycoparasitism can be an important mode of biocontrol of B. cinerea on host plants (63). ...
... It was reported in cultivated, grassland, woodland, forest, heathland, freshwater, and coastal soils, particularly those of neutral to alkaline pH (4,13,15,43). G. roseum is frequently associated with cysts of Heterodera spp., Globodera spp., and other nematodes in soil (6,18,24,26,36) and with sclerotia of Sclerotinia sclerotiorum, Phymatotrichum omnivorum, Rhizoctonia solani, Botrytis spp., Verticillium spp., and other fungi in soil and plant materials (25,51,61,62). Over the past 35 years, G. roseum has gained a distinctive reputation as a mycoparasite of a broad spectrum of fungi (3,30,35,37,59). ...
... This mode of action is important chiefly because it contributes to inoculum suppression of B. cinerea. G. roseum is a well-known mycoparasite of hyphae, spores, sclerotia, and fruiting bodies of numerous fungi, including B. cinerea (3,10,61). While a majority of studies were conducted on agar media, recent observations on raspberry indicated that mycoparasitism can be an important mode of biocontrol of B. cinerea on host plants (63). ...
... Investigation on the infection process of Glipdadium species have shown similar behaviour as Trichoderma spp. Walker and Maude (1975) showed that G. rosewn after coming in contact with Botrytis alli produced appressoria and later developed interacellular hyphae. A similar infection process has been observed on R. solani, by G. virens and on Eutypa armeniaca. ...
... Gliodadiwn rosewn and G. virens have been shown parasitic on wide variety of plant pathogens including Botrytis alli (Walker and Maude. 1975 (Moody and Gindrat. 1977). Rhzoctonia solani (Howell. 1982) and Sderotinia sderotiorum (Huang. 1978 andTu, 1980). ...
... The fungus Clonostachys rosea, of which three isolates were identified in this study, grows in a wide range of habitats, including soil, fungi, plant parts, nematodes, ticks, and insects (Walker and Maude 1975;Domsch et al. 1980;Mueller and Sinclair 1986;Schroers 2001;Haarith et al. 2020;Sun et al. 2020). Its ability to mycoparasitize other fungi has been used for the biological control of a wide range of plant pathogenic fungi affecting different crops and forest species (Yu and Sutton 1997;Mamarabadi et al. 2008;Rodriguez et al. 2011;Moraga-Suazo et al. 2016;Jensen et al. 2022). ...
The black timber bark beetle ( Xylosandrus germanus ) is a strongly invasive ambrosia beetle and an important forest pest in Slovakia. This pest is closely associated with symbiotic fungi used as its food source. We investigated the fungi associated with X. germanus adults in Slovakia. In this study, Beauveria bassiana , B. pseudobassiana , Clonostachys rosea , Fusarium oxysporum , Ophiostoma quercus , Phaeoacremonium scolyti , and Talaromyces amestolkiae were isolated and identified by morphological and molecular analyses. The fungus Ophiostoma quercus was most frequently isolated from living beetles, while the entomopathogenic Beauveria bassiana was the most commonly isolated from dead beetles. The morphological descriptions of fungi based on isolates from the surface of X. germanus adults are provided.
... Parasitized hyphae and sclerotia of R. solani were subsequently found to collapse and become nonviable. Host cell death caused by the formation of intracellular hyphae post host cell contact establishment was found in the case of G. virens on Botrytis allii Munn (Walker and Maude 1975) and B. cinerea (Li et al. 2002). ...
This first volume of a two-volume work presents the manifold applications of beneficial microbes and microbiomes in plant growth promotion, in enhancing crop resilience and in control of phytopathogens through microbial antagonists. In-depth insights into latest technologies such as biopriming of seeds and soil inoculation of rhizosphere microorganisms are provided.
The two-volume work “Microbial Biocontrol” introduces mechanisms of plant-microbe interactions and explores latest strategies of how microbes can be applied in biocontrol and management of plant pathogens, replacing chemical fertilizers and pesticides. The book covers different groups of microorganisms such as bacteria, fungi, but also the interplay of entire microbiomes, and reviews their specific benefits in crop growth promotion, in enhancing the plants’ tolerance against biotic and abiotic stress as well as in post-harvest management of various plant diseases. Novel tools such as CRISPR/Cas9 and microbe derived nanoparticles are also addressed besides the legal aspects of biocontrol applications.
Today, rising global population and changing climatic conditions emerge as a major challenge for agronomist farmers and researchers in fulfilling the requirements of global food production. The conventional agricultural practices utilize undistributed use of chemical fertilizers and pesticides to enhance growth and yield of agricultural products and fresh foods, but their extensive and continuous use have led to a range of negative consequences on the food quality and safety, to environment as well as to human and animal health. Microbial biocontrol applications are presented as a solution, paving the way to a sustainable agriculture in compliance with the UN Sustainable Development Goals (SDG).
... Parasitized hyphae and sclerotia of R. solani were subsequently found to collapse and become nonviable. Host cell death caused by the formation of intracellular hyphae post host cell contact establishment was found in the case of G. virens on Botrytis allii Munn (Walker and Maude 1975) and B. cinerea (Li et al. 2002). ...
“Bioprospecting” in general term means exploring various potential biological sources for a wide range of environmental and other related operation of social, biological, and commercial value, respectively. The utilization of microbial flora and communities ranging from fungal, algal, and bacterial also includes alterations in terms of genes, structures, materials, and metabolic behavior for implementation in economic development, conservation strategies related to biodiversity, sustainable management of natural resources, etc. The present chapter thus involves an overview regarding “bioprospecting of endophytes” in various aspects of sustainability, ecotoxicology, and environmental protection, due to their ability to develop a wide range of novel and bioactive compounds. Furthermore, these above advantages make endophytes potential candidates in industrial operations. The present endophytic research study is completely focused on plants inhabiting the microbial population of endophytes, as it increases plant growth, provides resistance against various diseases, and also enhances the ability to tolerate extreme external environmental conditions. The success of this endophyte research will be beneficial for the sustainability of the environment and agricultural science and also for mankind’s welfare.
... Parasitized hyphae and sclerotia of R. solani were subsequently found to collapse and become nonviable. Host cell death caused by the formation of intracellular hyphae post host cell contact establishment was found in the case of G. virens on Botrytis allii Munn (Walker and Maude 1975) and B. cinerea (Li et al. 2002). ...
Despite the advanced technology in agriculture, the majority of yield losses are caused by diseases and pests in the world. The developing new resistant cultivars and chemical control are the two most commonly used methods for preventing yield losses. However, the usage of chemicals during agricultural production disrupts the balance of a hidden ongoing warfare of which is being waged by various fungi against pathogens in the root rhizosphere. The way to prevent yield loss without disturbing the balance is to emerge as biological control or control pest and diseases by using living things over the past decades. The living things named as beneficial organisms have some specific mechanism of controlling pathogens in the rhizosphere zone; competition for space and nutrients, mycoparasitism, antibiosis, mycovirus-related prevention, siderophore, and induced systemic resistance. The aim of this chapter is to explain these mechanisms at the molecular level and reveal their relationship with agriculturally produced plants. In addition to these mechanisms, the chapter also explains some model organisms such as Trichoderma spp., AMFs, and their biocontrol activity at the molecular levels.
... A ocorrência de variações bruscas de temperatura na superfície do solo é a principal causa da perda de viabilidade dos escleródios. Escleródios de B. squamosa podem ser parasitados por Gliocladium roseum, como verificado por Walker & Maude (1975), sendo maior a atividade de micoparasitismo após germinação dos escleródios. ...
Government and public concerns about chemicals and their chemical residues including fungicides, bactericides, herbicides, etc. in food and degradation of soil and environment have stimulated interest for exploring the field of biological control. Subsequently, researching for new biological control agents and highlighting their importance in reduction of disease incidence and associated severity have opened channels for emerging and promising avenues for practical applications in the field of agriculture and ensuring low values of eco-toxicity. Many biocontrol agents produce antibiotics or extracellular or lytic enzymes, and this has provided important nuances regarding the nature and mechanistic processes associated with degradation events during the course of antagonism. Nevertheless, utilizing the biological properties of these potent antagonists comes only through an elaborate understanding of the mechanisms involved in these biological processes. In this context, fungal and bacterial antagonists active in reducing the inoculum density of the pathogen have grabbed considerable attention. Antagonists act against pathogens through mycoparasitism and antibiosis. Mycoparasitism refers specifically to parasitism of one fungus by another fungus. This encompasses several kinds of interactions, such as coiling of the hyphae, penetration, haustorium production, and hyphal lysis. Antagonists produce toxic metabolites near the interaction court of the pathogen, and thus they inhibit their growth by antibiosis. Extensive research related to interactions between the disease-causing pathogen and the mycoparasite would help in devising new ways of reducing the amounts of bioagents needed for controlling the disease at desirable levels.
Because the common soil fungus and mycoparasite Gliocladium roseum differs from the type species of Gliocladium, G. penicillioides, in morphology, ecology, teleomorph, and DNA sequence data, it is classified in a separate genus, Clonostachys. Penicillium roseum is the oldest available name for G. roseum and is recombined as C. rosea. Penicillium roseum, described from potato in Germany, is neotypified by a conidial isolate originating from a fungal substratum in European soil. By choosing this strain as neotype for P. roseum the epithet is formally linked to the common soil fungus used in the biocontrol of fungal plant pathogens. The anamorph of Bionectria ochroleuca (Hypocreales) is morphologically indistinguishable from C. rosea; both morphs are redescribed. Bionectria is generically distinct from Nectria s. s. and is the appropriate genus for species of the Nectria ochroleuca group. The anamorph genus Gliocladium s. s. is associated with teleomorphs in Sphaerostilbella and Hypocrea series Pallidae. With the separation of Clonostachys from Gliocladium and Bionectria from Nectria the generic classification reflects natural relationships. A generic circumscription is proposed for Clonostachys and compared with Gliocladium. Nectriopsis sporangiicola and Roumegueriella rufula are related to Bionectria but have distinct Gliocladium-like anamorphs. Based on morphological features, Rhopalocladium myxophilum gen. et sp. nov. is proposed for the anamorph of N. sporangiicola. The anamorph of Roumegueriella rufula is generally found in association with the teleomorph and is referred to as Gliocladium-like.
Mycoparasites have much potential for biocontrol of plant pathogens. They can be applied as commercially produced inoculants or, equally important, they can be exploited as natural regulators of pathogen populations by appropriate manipulation of crops or soils (Adams, 1990; Baker, 1987; Boogert et al., 1990; Fahima and Henis, 1990; Lumsden and Lewis, 1989). In either case it is important to understand their modes of action against target pathogens and the ecological factors that influence their activities. Several themes have begun to emerge from these studies, and they show parallels with events in other host-parasite interactions (Chet, 1987; Manocha and Chen, 1990). So this seems an appropriate time to assess the state of knowledge and draw attention to areas of neglect.
Conidia and germ tubes of Botrytis cinerea were highly susceptible to infection by the mycoparasite Gliocladium roseum, when both organisms were grown as a mixed culture in sterile water containing 8-9×104 pollen grains of alfalfa per ml solution. Scanning electron microscopic studies revealed that infection of conidia and germ tubes occurred through direct penetration by hyphal tips of G. roseum without the formation of appressoria. Transmission electron microscopic studies indicated indentation and rupture of the host cell walls at penetration sites. The parasitized conidia and germ tubes of B. cinerea showed signs of cytoplasmic disintegration and the presence of hyphae of G. roseum.
Hypomyces aurantius inhibited the growth of some known basidiomycete hosts in dual culture experiments. Vacuolation and bursting of hyphae of hosts was commonly observed in mycelial interaction zones, but coiling was exceptional and penetration of host hyphae never observed. H. aurantius produced a diffusible non-specific toxin which took effect some distance away from the mycelium. The fungicidal toxin produced rapid and irreversible permeability changes in host hyphal membranes.
The effect of thermophilic compost on onion diseases and seedling quality used as basic fertiliser or bed cover was evaluated. The research was carried out in 1993 and 1994 in Ituporanga, Santa Catarina State, Brazil. Three experiments were conducted in randomised blocks with six replicates. The treatments were thermophilic compost, mineral fertilizer and organic-mineral fertilisers. In another experiment, the compost and the mineral fertiliser were combined with six plant densities in a factorial design experiment. For the seed bed coverage, new and one-year-old Pinus sawdust, soil, and thermophilic compost were evaluated using a randomised block design with four replicates. Thermophilic compost showed higher emergence and survival of onion transplants than organic-mineral and mineral fertiliser. The thermophilic compost increased the survival of onion transplants (101.4 pl/m²) and reduced Botrytis squamosa intensity (51.7%) when compared with the mineral fertiliser (87.7 pl/m² and 56.8%) regardless of plant density. Onion seedlings grown on seedbeds covered with compost presented higher emergence (146.1 pl/m²) and survival of seedlings (134.8 pl/m²) than those grown using only soil as coverage (90.2 and 77.5 pl/m², respectively). The occurrence of damping-off did not differ between treatments with fertilisers alone or treatments in which coverage was used in the seedbed.
Because the common soil fungus and mycoparasite Gliocladium roseum differs from the type species of Gliocladium, G. peniclllioides, in morphology ecology, teleomorph, and DNA sequence data, it is classified in a separate genus, Clonostachys. Penicillium roseum is the oldest available name for G. roseum and is recombined as C. rosea. Penicillium roseum described from potato in Germany, is neotypified by a conidial isolate originating from a fungal substratum in European soil. By choosing this strain as neotype for P. roseum the epithet is formally linked to the common soil fungus used in the biocontrol of fungal plant pathogens. The anamorph of Bionectria ochroleuca (Hypocreales) is morphologically indistinguishable from C. rosea; both morphs are redescribed. Bionectria is generically distinct from Nectria s. s. and is the appropriate genus for species of the Nectria ochroleuca group. The anamorph genus Gliocladium s. s. is associated with teleomorphs in Sphaerostilbella and Hypocrea series Pallidae. With the separation of Clonostachys from Gliocladium and Bionectria from Nectria the generic classification reflects natural relationships. A generic circumscription is proposed for Clonostachys and compared with Gliocladium. Nectriopsis sporangiicola and Roumegueriella rufula are related to Bionectria but have distinct Gliocladium-like anamorphs. Based on morphological features, Rhopalocladium myxophilum gen. et sp. nov. is proposed for the anamorph of N. sporangiicola. The anamorph of Roumegueriella rufula is generally found in association with the teleomorph and is referred to as Gliocladium-like.
Morphological development and interactions of Glioclodium roseum and Botrytis cinerea on leaves, stems, and stemens of Taspberry were examined by light microscopy. Tissues were inoculated with conidial suspensions of the antagonist, the pathogen, or both, and kept in continuous high humidity at 21-23°C. In the absence of B. cinerea, G. roseum produced germ tubes and superficial hyphae with short side branches that penetrated the host. No symptoms developed, but numerous conidiophores and conidia of G. roseum were observed on tissues at 40-72 h after inoculation. In the absence of G. roseum, B. cinerea germinated slowly on leaves but rapidly on stems and stamens. The pathogen produced a few single-lobed appressoria on leaves, various kinds of appressoria on stems, and a range of appressoria and infection cushions on stamens. After coinoculation, G. roseum strongly suppressed germination and germ tube growth of B. cinerea on leaf surfaces. On stems the antagonist moderately suppressed germ tube growth and intensely parasitized the pathogen. Hyphae of G. roseum grew on, coiled around, penetrated, and developed within hyphae and conidia of B. cinerea. On stamens, G. roseum reduced colonization incidence of the tissues but did not suppress germination, growth, or formation of appressoria and infection cushions by B. cinerea, or intensely parasitize the pathogen. Available nutrients are postulated to determine the mode of antagonism on the various organs. G. roseum suppressed sporulation and, by inference, infection and colonization of B. cinerea in raspberry tissues more effectively when applied before or at the same time as the pathogen than after the pathogen. It is concluded that G. roseum is a nonpathogenic parasite of raspberry with flexible modes of antagonism towards B. cinerea in this host.
Neck rot (Botrytis allii) affected bulbs of onions for 2 successive years when these were grown either in the field in soil from which an infected crop had been cleared 6 months previously or when infected debris was incorporated into field soil 6 months before the first crop was sown. These sources did not continue to cause infection of onion crops grown on the contaminated areas in the four succeeding years.
The white storage tissue of onion bulbs (healthy or infected) persisted for less than 6 months in unsterile field soil contained in pots while sclerotia present in similar soil varied in their rate of decay but lost their capacity to produce conidiophores of B. allii after 6 months. In one sample, sclerotia were not recovered after 5 months; Gliocladium roseum, a mycoparasite, was present in this sample and may have affected survival.
Sclerotia of Botrytis cinerea were found to be a source of primary inoculum for bunch rot of grapes in the Hunter Valley of New South Wales. Conidia-bearing sclerotia were found on canes on grapevines. Resporulation of sclerotia was observed and sporogenic germination led to infection of flowers and berries. Sclerotia survived for eight months in untreated soil in the laboratory. Application of dicarboximides (procymidone, iprodione and vinclozolin) reduced infection of flowers and bunch rotcaused by the sporogenic germination of sclerotia.ZusammenfassungSklerotien von Botrytis als Primrinokulumquelle für Traubenfule in New South Wales, AustralienSklerotien von Botrytis cinerea wurden als Primrinokulumquelle für Traubenfule in Hunter Valley, New South Wales festgestellt. Sklerotien, die Konidien tnigen, wurden an Rebholz gefunden. Die Wiedersporulienmg der Sklerotien wurde beobachtet und führte zum Befall der Blüten und Beeren. Die Sklerotien überlebten 8 Monate in unbehandelter Erde im Labor. Die Verwendung von Dicarboximide (Procymidon, Iprodion und Vinclozolin) verringerte Blütenbefall und Traubenfule, die durch Konidienbildung der Sklerotien verursacht wurde.
A few soil-borne plant pathogens have been controlled successfully by commercial formulations of biocontrol agents, but many attempts to develop biocontrol inoculants, although promising under experimental conditions, have met with difficulties in practice. The reasons for this are discussed in this review, which outlines some of the major findings on the behaviour of microbial inoculants in soil. It is emphasized that biocontrol also occurs naturally in current agricultural practice and can be exploited purposely, but it is vulnerable to disruption by agrochemicals or mismanagement. The future of biocontrol of soilborne plant pathogens probably lies in integrated (biorational) control systems that combine the use of commercial inoculants, where appropriate, with management practices that maintain and enhance the natural biocontrol systems.
Gliocladium roseum was found to be the most common and probably the most effective mycoparasite in potato fields in the northern parts of the Netherlands. It is able to parasitize and kill living hyphae at temperatures of 12°C and higher. Sclerotia of R. solani are often infected and killed by this fungus under suitable conditions, i.e. at temperatures of 16°C and more. Killing of sclerotia by other antagonistic organisms was also observed. It is also shown by not parasitic fungi and is caused by toxins produced by the antagonist. The development of the G. roseum population was studied during the growth of a potato crop in two soils. In both soils its initial level was very low. In both a slightly acid sandy soil and a neutral sandy loam, suppression of R. solani can occur;G. roseum accumulated in the former mainly under continuous potato crops, Colletotrichum coccodes was the main antagonist in the latter. © 1979 Koninklijke Nederlandse Planteziektenkundige Vereniging.
A number of Botrytis species are pathogens of bulb crops. Botrytis squamosa (teleomorph= Botrytotinia squamosa) causal agent of botrytis leaf blight and B. allii the causal agent of botrytis neck rot are two of the most important fungal diseases of onion. The taxonomics of several of
the neck rot pathogens of onion have been revised on the basis of recent molecular sequence analysis studies. B. allii, B. aclada, and B. byssoidea are now recognized as distinct species causing neck rot diseases of onion. B. cinerea is also pathogenic on onion, primarily causing botrytis brown stain on onion bulbs. B. tulipae, B. elliptica, and B. gladiolorum are important pathogens of flower bulbs and are the causal agents of leaf blight in tulip, lily, and gladiolus, respectively.
Leaf blight in the major flower bulb crops is called ‘fire’ referring to the fire-like symptoms occurring on the leaves of
flower bulb plants when epidemics occur in production fields. In both the onion and flower bulb production systems chemicals
are still heavily relied upon to control the major diseases, however, alternative disease management systems also are used
and undoubtedly will become increasingly important in controlling the diseases. Infected plants and colonized plant debris
are considered important sources of inoculum for B. squamosa, B. tulipae, and B. elliptica, particularly when sclerotia are formed. Sclerotia of B. squamosa serve as the source of conidia, as well as apothecia producing ascospores, in onion production areas in New York. The primary
inoculum sources of B. allii and B. gladiolorum are believed to be infested seed and infected corms, respectively.
Four fungal species were recorded in vitro as potential mycoparasites of sclerotia of Sclerotium cepivorum, the causal agent of onion white rot. Parasitised sclerotia appeared shrunken and decayed and failed to germinate. Light
and scanning electron microscopy revealed colonisation of the internal structure of the sclerotium by the mycoparasites. The
medullary region was progressively destroyed but the rind cells remained relatively intact. The surface of parasitised sclerotia
was extensively covered by spores or fruiting bodies of the mycoparasites. The results indicate that the four test fungi show
potential for biological control of the disease.
Preparations of glucanases from Gliocladium roseum Bainier degraded glucans in Botrytis allii Munn hyphae. Increased β1–3 glucanase activity and the formation of chitinase occurred in cultures of B. allii parasitized by G. roseum. These results indicated that the disintegration of hyphal walls during parasitic attack was probably due to heterolytic enzyme action.Substances toxic to the host were detected in parasitized cultures; these were stable, partly, at least, of low molecular weight and effective over short distances only.Coagulation of cytoplasm and disintegration of hyphal walls occurred without physical contact between the hyphae of the two species; coiling of G. roseum hyphae around those of the host was infrequent and penetration rare, indicating that intimate contact between hyphae is not an essential part of the necrotrophic attack.
Protoplast isolation and regeneration from 24 h germinating conidia of Gliocladium catenulatum, G. roseum and G. virens have been optimized. The number of nuclei per cell of four cell types of the Gliocladium spp. was determined. The optimal enzyme combination for protoplast production contained chitinase, lyticase and cellulase onuzaku in 0.5 M mannitol osmoticum. The quantity of protoplasts produced was dependent on the duration of enzymatic digestion, the concentration of germinating condidia and the species of Gliocladium being assayed. A maximum of 11 to 55% of the protoplasts of wild-type Gliocladium spp. and of two double amino acid autoxotrophic mutants of G. roseum (both Met− Leu−) regenerated to mature, conidiating colonies depending on the regeneration medium utilized and the strain assayed. Protoplasts of G. roseum and G. catenulatum were approximately 4% multinucleate, 56% uninucleate and 40% anucleate. Protoplasts of G. virens were approximately 81% multinucleate, 6% uninucleate and 13% anucleate. Regenerating protoplasts and germinating conidia of G. catenulatum and G. roseum were predominantly uninucleate; those of G. virens were predominantly multinucleate. Conidia of all three Gliocladium spp. were predominantly uninucleate.
In studies using light and scanning electron microscopy it was clearly demonstrated that Nectria inventa, Gliocladium roseum, G. ca.tenula.tum, Clonostacbys sp., Sesquidllium sp., Verticillium nigrescens, Dicyma olivacea, Stachybotrys elegans, Myrothecium carmichaelii, M. cinctum, M. roridum, M. tongaense, M. verrucaria and Coniothyrium sporulosum are able to parasitize Alternaria alternata. With the exception of N. inventa and the five Myrothecium spp., none of the other fungi has been previously reported to be mycoparasitic on Alternaria. Moreover, there is no current information about the mycoparasitic and antibiotic activity of the genera Clonostacbys and Sesquici-lium.
The mode of parasitism was nearly the same in all of the mycoparasites. In many cases, penetration was achieved directly by the hyphal tips without the formation of appressorium like structures (ALS) and there was no evidence that the formation of ALS was a prerequisite for penetration. Dependant on the severity of infection, a gradual shrinkage, distortion and an eventual collapse of the parasitized conidia were observed. A bursting and total collapse of the spores without any penetration was detected by the antibiotic producing mycoparasites such as G. roseum, G. CAtenulatum, Clonostacbys sp., Sesquicillium sp., D. olivacea and the five Myrothecium species.
In consideration of their activity, all of the tested antagonists would appear to be candidates for in vivo investigations to check their suitability as biocontrol agents.
Typescript (photocopy). Thesis (M.S.)--Oregon State University, 1979. Includes bibliographical references.
Application of nitrolim, which contains 57% calcium cyanamide, to the soil surface completely inhibited germination of sclerotia of Sclerotinia sclerotiorum , whether buried or placed on the soil surface, over a period of at least 20 weeks at 20°C, whereas most sclerotia on untreated soil germinated within 5 weeks, producing apothecia 2–6 weeks later. Temperature markedly influenced the germination rate of sclerotia. On untreated soil, sclerotia failed to germinate at 10° after 4 weeks, and at 15° only one-third had germinated. Hydrogen cyan-amide was a less effective inhibitor of germination than nitrolim. Benlate and benzotriazole inhibited germination of sclerotia over a period of at least 20 weeks at 20° but parabanic acid had no effect. Initial inhibition by maleic acid hydrazide was followed by normal germination and the formation of apothecia.
It is proposed that ‘fungal biological floras’ should be prepared, incorporating a common range of data. Gliocladium roseum is discussed under the headings Taxonomy, Ecology and Physiological Attributes. Its roles as a true soil fungus and as an inhabitant of mature salt marshes are considered in relation to its physiological activities and its known antifungal attributes.
Investigations were carried out on Schrotinia serica , two strains of S. Sclerotiorum de Bary, five strains of S. Trifoliorum Eriks., two forms of S. minor Jagger, four isolations of a Sclerotinia from Vicia Faba considered to be a variety of Sclerotinia Trifoliorum , and a variant which arose from one of these isolations.
Their pathogenicity to several different plants was tested and the fungi were found to fall into three groups: (1) S. Sclerotiorum and S. minor , (2) S. Trifoliorum and its variety Fabae , and (3) S. serica.
A variant with light brown sclerotia which arose from S. Trifoliorum var. Fabae differed from the parent form in pathogenicity.
Ascospores of S. Sclerotiorum, S. minor and S. Trifoliorum did not infect healthy leaves.
The production of mycelium by sclerotia in the soil was not observed.
S. serica differed from the other fungi in that it produced numerous apothecial stipes and several apothecia in test‐tube cultures.
Exposing sclerotia to different conditions of temperature and moisture after their removal from culture and before their burial in damp sand did not hasten apothecial production.
Sclerotia formed in cultures grown over a wide temperature range produced apothecia when subsequently buried in damp sand.
Single‐spore lines of S. serica, S. Sclerotiorum, S. minor and S. Trifoliorum produced apothecia.
Apothecial production took place over a wide temperature range.
Apothecia of one form of S. minor arising from sclerotia formed on sterilized vegetables were larger than those from sclerotia formed on malt‐extract. The dimensions of the apothecia are given and a description of the apothecia of S. Sclerotiorum, S. minor, S. Trifoliorum and S. Trifoliorum var. Fabae.
Measurements are given of asci and ascospores.
The minimum, maximum and optimum temperatures fpr linear spread of mycelium are given: also the time taken by cultures to reach a diameter of 6 cm. at 207deg;C. The view is expressed that such data should not be used for differentiating species. S. serica spread more slowly than the other species. The variant of S. Trifoliorum var. Fabae had different temperature relations from the parent form.
A brief description is given of the cultural appearance of S. Sclerotiorum, S. Trifoliorum, S. minor, S. Trifoliorum var. Fabae and its variant.
The classification of the fungi is discussed.
For a study of the colonisation of the IJsselmeerpolders by fungi, attention was fixed on the cellulose-decomposing fungi, since these are considered to represent the more stable part of the mycoflora of soils. If one assumes that in the North East Polder, cultivated for approximately 25 years, the fungal population is approaching stability, the progress of colonisation of the younger polders can be judged by comparison of the number of species found and their frequency.
It is shown that the progress of fungal colonisation did not depend only on the time during which a soil has been dry, but also on the use that has been made of it. Of the species known as antagonists of other fungi,Trichoderma spp. provided an increasingly larger proportion of the total population as the soils were further from stability.
It is concluded that the increase of fungal antagonists may well be one of the causes of the decline of such parasites asOphiobolus graminis andRhizoctonia solani. Special mention is made ofGliocladium roseum, the parasitism of which towardsR. solani could be demonstrated in paired cultures.
Zusammenfassung Aus den Kulturfiltraten einerGliocladium-Art lassen sich im wesentlichen drei Substanzen isolieren, und zwar Rubrogliocladin (C20H26O8), Aurantiogliocladin (C10H12O4) und Gliorosein (C10H14O4). Alle drei Verbindungen besitzen eine nur geringe antibiotische Wirksamkeit. Im Rubrogliocladin liegt ein Chinhydron I vor. Diese Molekelverbindung setzt sich aus äquimolaren Mengen des Chinons, Aurantiogliocladin II, und des entsprechenden Hydrochinons III zusammen. Letzteres kann leicht durch Reduktion von Rubrogliocladin und Aurantiogliocladin erhalten werden. Dieses Hydrochinon stellt eine mit dem natürlich vorkommenden Gliorosein isomere Verbindung dar.
Control of sclerotiniose of celery on Florida muck The production of apothecia of Sclerotinia sclerotiorum and S. trifoliorum in culture
- References Brooks
- A N 7°
- L Henson
- W D Valleau
REFERENCES BROOKS, A. N. (1940). Control of sclerotiniose of celery on Florida muck. Phytopathology 3 0,7°3. HENSON, L. & VALLEAU, W. D. (1940). The production of apothecia of Sclerotinia sclerotiorum and S. trifoliorum in culture. Phytopathology 30, 869-873.