Endoparasites of soil nematodes and rotifers II The genus Haptocillium (original) (raw)
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Two new species of Haptoglossa, H. erumpens and H. dickii, infecting nematodes in cow manure
Mycological Research, 2000
Two species of Haptoglossa isolated from nematodes from cow manure from N.E. England are described. H. erumpens sp. nov., infecting Bunonema nematodes, is aplanosporic, the cysts being released after rupture of the nematode cuticle in the absence of an evacuation tube. H. dickii sp. nov. is zoosporic, infecting several species of rhabditid nematodes. Aplanospores and zoospore cysts germinated to produce secondary spores (gun cells) with which to infect further nematode hosts. Some key ultrastructural features in both species have been included. Haptoglossa (Drechsler, 1940) comprises obligately endoparasitic fungi which infect nematodes and rotifers. There are presently six species, four of which are zoosporic and two of which are aplanosporic (
Nematophagous Fungi as Root Endophytes
Nematophagous fungi constitute a group of fungal antagonists to nematodes. The latter arc small roundworms living in soil and water. Most nematodes are saprotrophic, but many species are parasites of plants and animals (Poinar 1983). The nematophagous fungi have been suggested as promising candidatesfor bioiogical control of parasitic nematodes (Stirling 1991), but so far no successful commercial products have been .presented.
Soil Biology and Biochemistry, 1988
A "dilution plate assay" was developed to quantify parasitism of C. xenoplux by H. rhossiliensis. Aliquots of C. xenoplax in suspension (treated with 0.5% NaOCl after extraction from soil by wet sieving and centrifugation) were spread onto 1.5% water agar plates supplemented with 200 parts 10e6 streptomycin sulfate. After 5 days at 22 k Z'C, the numbers of C. xenoplax with or without sporulating H. rhossiliensis were determined using a dissecting microscope. The assay was used to measure the rate of decay (disappearance) of parasitized C. xenoplax in field samples incubated in the laboratory. Time required for 50% reduction in number of parasitized nematodes (averaged across all life stages) incubated at-33 kPa soil water potential and at IO, I5 or 2o'C was 61 , 26 or I6 days, respectively. Rate of decay was much faster for parasitized second-and third-stage juveniles than for parasitized fourth-stage juveniles and adults. Rate of infection can be estimated if the number of parasitized nematodes and rate of decay of such nematodes are known INTRODUCl'ION Criconemellu xenoplux Nordbrina-Hertz B. (1987) Ouantification of nredatorv and endoparasitic nematophagous fungi in soil. ,Wicrobial Ecology 13. 89-93. Day P. R. (1965) Particle fractionation and particle-size analysis. In Merhod.s of Soil Analysis. I. (C. A. Black. Ed.). pp. 545-567. American Society of Agronomy. Madison. Gray N. F. (1984) Ecology of nematophagous fungi: com
Frontiers in Fungal Biology
In this review, we supply a framework for the importance of nematophagous fungi (nematophagous fungi [NF]) and their role in agricultural ecosystems. We characterize the taxonomy, diversity, ecology, and type of NF, depending on their interaction with plant-parasitic nematodes (PPNs). We described potential mechanisms of NF in the control of PPNs, the efficiency and methods of utilization, and the use of nematicides in sustainable agriculture. We explain the utilization of NF in nanotechnology as a new approach. NF are significant in the soil for having the effective potential for use in sustainable agriculture. These types of fungi belong to wide taxa groups, such as Ascomycota, Basidiomycota, and other groups. Diverse NF are available in different kinds of soil, especially in soils that contain high densities of nematodes. There is a relationship between the environment of nematodes and NF. NF can be divided into two types according to the mechanisms that affect nematodes. These t...
Fungal and Bacterial Endophytes as Microbial Control Agents for Plant-Parasitic Nematodes
International Journal of Environmental Research and Public Health
Endophytes are symbiotic microorganisms that colonize plant tissues and benefit plants in multiple ways including induced systemic resistance to biotic and abiotic stresses. Endophytes can be sustainable alternatives to chemical nematicides and enhance plant health in a variety of cropping and natural environments. Several in vitro and in vivo studies demonstrated the potential of multiple species of Fusarium and Bacillus against plant-parasitic nematodes in horticultural, agricultural, and fodder crops and in forestry. While there were efforts to commercialize some of the endophytes as bionematicides, a lack of good formulations with consistent field efficacy has been a major hurdle in commercializing endophytes for nematode control. Identification of efficacious and environmentally resilient strains, a thorough understanding of their modes of action, interactions with various biotic and abiotic factors, and developing strategies that improve their effectiveness are critical areas ...
Nematophagous fungi: new species of the Lagenidiales endoparasitic on Rhabditis
Antonie van Leeuwenhoek, 1976
Two new species of the Lagenidiales endoparasitic on the nematode Rhabditis are reported from Ontario soils. In Myzocytium lenticulare the biflagellate zoospores encyst at any point on the cuticle of the host and penetrate directly through the wall. Sexual reproduction in this species is by oogamy. The antheridial protoplast migrates through a pore in the adjacent wall and fuses with the oogonial protoplast to produce a thick-walled reticulate oospore. In Lagenidium caudatum large biflagellate zoospores encyst at or near the body orifices of the host. Many of the zoospores possess a distinct tail-like appendage. Germination tubes from the encysted zoospores penetrate the body orifices to infect the host. The thallus in this species is distinctive in being composed of narrow, irregular hyphae which fill the host. No sexual stage is known.
Evolution of parasitism in nematode-trapping fungi
PubMed, 2003
We are studying the evolution of parasitism in a group of soil-living ascomycetes that can grow as saprophytes as well as parasites by forming special morphological structures called traps. Analyses of 18S ribosomal DNA sequences have shown that these fungi form a monophyletic and isolated clade among the ascomycetes. The phylogenetic patterns within this clade are concordant with the morphology of the traps and separate species having adhesive traps (nets, knobs, and branches) from those having constricting rings. This suggests that these nematode-trapping fungi have a common ancestor, and that the ability to capture nematodes has been an important trait for further speciation and diversification within the clade. To obtain information on the genomic basis for this pattern, we recently started a large-scale sequencing project of the nematode-trapping fungus Monacrosporium haptotylum. This will allow the identification of genes uniquely expressed during the development of traps, and elucidate the molecular evolution of such genes within the nematode-trapping fungi clade.
Fungi–Nematode Interactions: Diversity, Ecology, and Biocontrol Prospects in Agriculture
Journal of Fungi
Fungi and nematodes are among the most abundant organisms in soil habitats. They provide essential ecosystem services and play crucial roles for maintaining the stability of food-webs and for facilitating nutrient cycling. As two of the very abundant groups of organisms, fungi and nematodes interact with each other in multiple ways. Here in this review, we provide a broad framework of interactions between fungi and nematodes with an emphasis on those that impact crops and agriculture ecosystems. We describe the diversity and evolution of fungi that closely interact with nematodes, including food fungi for nematodes as well as fungi that feed on nematodes. Among the nematophagous fungi, those that produce specialized nematode-trapping devices are especially interesting, and a great deal is known about their diversity, evolution, and molecular mechanisms of interactions with nematodes. Some of the fungi and nematodes are significant pathogens and pests to crops. We summarize the ecolo...
2007
This review discusses the taxonomy, patterns of sporogenesis and modes of infection of a group of little studied holocapic pathogens of bactivorous nematodes (and rotifers) from terrestrial and marine habitats. These holocarpic obligate parasites have been traditionally placed within the "Iagenidiaceous oomycetes" although Haptoglossa had been placed in the Saprolegniales. The nematode pathogens that will be discussed fall within the genera C/amydomyzium, Gonimocheate, Haptoglossa and Myzocytiopsis. The patterns of asexual and sexual sporogenesis will be described in detail in the light of recent ultrastructural studies that we have undertaken. We conclude by discussing the main infection strategies employed by these organisms which we categorise into active and passive types. In the former, zoospores actively locate their host (by chemotaxis) and encyst on the host surface immediately prior to infection. In the latter types, the zoospores or aplanospores rapidly germinate...
Nematophagous Fungi: A Biological Agent for Regulation of Plant Parasitic Nematodes
Agriculture Journal IJOEAR, 2020
The occurrence of plant-parasitic nematodes amongst farmers around the globe is a major concern. Farmers also turn to organic pesticides as an additional method to combat pests and diseases. Nematicides are widely available and of significant toxicity in the natural environment, for example, Aldicarb (Temik). Meanwhile, one of the major components of Integrated Pest Management (IPM) is the biological control using other organisms. Many microorganisms predate nematodes, but only handfuls are used for commercial purposes. In addition, the success of a nematode check is strengthened by a combination of two or more biocontrol agents. Fungi can be an efficacious biocontrol agent in particular, and can be feasibly obtained on a large scale. This review would include an outline of the different biomonitoring processes of technological development, but more on the morphological and biochemical dimensions and interactions of nematophagous fungi must be made available. This analysis will contribute to more nematodes and fungal biodiversity resources.