A Method for Using Commercial ELISA Tests to Detect Zoospores of<i>Phytophthora</i>and<i>Pythium</i>Species in Irrigation Water

Ali‐Shtayeh, Mohammed S.; MacDonald, J. D.; Kabashima, John N.

doi:10.1094/pd-75-0305

Cited by 58 publications

(21 citation statements)

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“…Following inoculation, five 1-liter samples of filtered water were collected from each of the SSF columns (20). Each 1-liter sample was assayed for the presence of Phytophthora CFU by using the membrane filtration technique of Ali-Shtayeh et al (2). Filter pieces from this were placed in universal bottles containing 5 ml of resuspension medium and placed on a rotary arm flask shaker FIG.…”

Section: Methodsmentioning

confidence: 99%

Spatial and Temporal Analysis of the Microbial Community in Slow Sand Filters Used for Treating Horticultural Irrigation Water

Calvo-Bado

Pettitt

Parsons³

et al. 2003

Appl Environ Microbiol

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An experimental slow sand filter (SSF) was constructed to study the spatial and temporal structure of a bacterial community suppressive to an oomycete plant pathogen, Phytophthora cryptogea. Passage of water through the mature sand column resulted in complete removal of zoospores of the plant pathogen. To monitor global changes in the microbial community, bacterial and fungal numbers were estimated on selective media, direct viable counts of fungal spores were made, and the ATP content was measured. PCR amplification of 16S rRNA genes and denaturing gradient gel electrophoresis (DGGE) were used to study the dynamics of the bacterial community in detail. The top layer (1 cm) of the SSF column was dominated by a variable and active microbial population, whereas the middle (50 cm) and bottom (80 cm) layers were dominated by less active and diverse bacterial populations. The major changes in the microbial populations occurred during the first week of filter operation, and these populations then remained to the end of the study. Spatial and temporal nonlinear mapping of the DGGE bands provided a useful visual representation of the similarities between SSF samples. According to the DGGE profile, less than 2% of the dominating bands present in the SSF column were represented in the culturable population. Sequence analysis of DGGE bands from all depths of the SSF column indicated that a range of bacteria were present, with 16S rRNA gene sequences similar to groups such as Bacillus megaterium, Cytophaga, Desulfovibrio, Legionella, Rhodococcus rhodochrous, Sphingomonas, and an uncharacterized environmental clone. This study describes the characterization of the performance, and microbial composition, of SSFs used for the treatment of water for use in the horticultural industry. Utilization of naturally suppressive population of microorganisms either directly or by manipulation of the environment in an SSF may provide a more reproducible control method for the future.Fungal plant diseases are a major problem within the horticultural industry, resulting in reduced yields and occasionally major crop damage. Contaminated irrigation water has long been recognized as an important source of fungal plant pathogens and is an important factor in disease spread on commercial horticultural nurseries (4). Water from many commonly used sources, such as rainwater from glasshouse roofs and, in particular, water stored in open reservoirs and ponds, can often contain large numbers of infective propagules of fungal plant pathogens, such as Pythium and Phytophthora spp. (1,4,34,46,48,53). A particularly high risk of disease spread is associated with the collection, recycling, and reuse of irrigation water, often referred to as recirculation (45,57,58), which is becoming more popular as attempts are increasingly being made to conserve valuable water supplies. Rapid dispersal of the pathogen in water is often achieved by asexual flagellate zoospores, and a key element for pathogen control is the removal of zoospores from water supplies. A wide...

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Section: Methodsmentioning

confidence: 99%

Spatial and Temporal Analysis of the Microbial Community in Slow Sand Filters Used for Treating Horticultural Irrigation Water

Calvo-Bado

Pettitt

Parsons³

et al. 2003

Appl Environ Microbiol

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“…recovered reacted positively also with Phytophthora Kits, but negatively with Pythium Kits. With a relatively simple filter-extraction procedure, ELISA kits effectively detected Phytophthora and Pythium in water samples (Ali-Shtayeh et al 1991). The presence of viable zoospores of Pythium sp.…”

Section: Immunoassaysmentioning

confidence: 99%

Detection of Fungal Pathogens in the Environment

Narayanasamy¹

2010

Microbial Plant Pathogens-Detection and Disease Diagnosis:

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The presence of fungal pathogens in the environment has to be detected and also quantified rapidly and precisely, because the inoculum for infection of crop plants comes from the pathogen propagules present in the soil, water, air and alternative host plant species. Soilborne pathogens may have different degrees of saprophytic ability, utilizing the organic matter present in the soil for their survival in the absence of crop plants. They produce different structures such as chlamydospores and sexual spores that are long-lived and are capable of surviving in the soil for several years. Fungal structures may be carried by irrigation water or rain water from one part of the field to other parts or to different fields. It has been possible to detect and identify the fungal pathogens in the irrigation water, recycled water used for growing hydroponic plants and also in wash water in the storage facilities for fruits and vegetables. The pathogens infecting aerial plant parts/organs are generally disseminated by wind to different locations. Traditionally spore traps have been used for assessing the spore load of air. Various biological, immunological and nucleic acid-based techniques have been employed for the detection, identification and quantification of pathogen propagules in the environment. Significant improvements have been made in the sensitivity and specificity of detection of fungal pathogens by applying immunoassys and nucleic acid-based methods that are capable of providing reproducible results rapidly and reliably. The relative usefulness and limitations of the detection techniques applied for the detection of fungal pathogens in the environment are discussed.Studies on the ecology of plant hosts provide information on the influence of environment on the growth and development of plants. Likewise, the influence of the environment on the microbial plant pathogens is studied to understand the extent of population build up resulting in the incidence of diseases in different agroecological conditions. Crop husbandry techniques aim to increase the crop yield to the maximum levels. But some of these techniques like monoculture and excessive application of nutrients may provide favorable conditions for pathogen development. Epidemiology deals with effects of biotic and abiotic environments on disease development in plant populations. Microbial pathogens multiply at different rates in a given set of environmental conditions and exhibit wide variations in their pathogenic potential (aggressiveness). The crop plants also have varying growth

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“…The probe could serve as a diagnostic tool to detect P. insidiosum in such environments and to differentiate it from other Pythium species that may be present and harmless to animal hosts. Commercial kits are available that use ELISA to detect Pythium and Phytophthora zoospores in irrigation water (2). In addition, polyclonal antibodies (1) and competitive PCR (38) have been used to detect the zoospores of P. porphyrae in seawater from Porphyra cultivation farms.…”

Section: Vol 42 2004 Species-specific Probe For Pythium Insidiosum mentioning

confidence: 99%

Development of a Species-Specific Probe forPythium insidiosumand the Diagnosis of Pythiosis

et al. 2004

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Pythium insidiosum, the only species in the genus that infects mammals, is the etiological agent of pythiosis, a granulomatous disease characterized by cutaneous and subcutaneous lesions and vascular diseases. Accurate diagnosis of pythiosis and identification of its causal agent are often inconsistent with current immunological diagnostic methods. A species-specific DNA probe was constructed by using a 530-bp HinfI fragment from the ribosomal DNA intergenic spacer of P. insidiosum. When the probe was incubated with dot blots of genomic DNA from 104 Pythium species, it hybridized only to the DNA of P. insidiosum and P. destruens-two species that have been considered conspecific. The probe also hybridized to DNA from 22 P. insidiosum isolates in this study, regardless of their geographic origin or animal host. When tested against genomic DNA from other pathogenic organisms (Aspergillus fumigatus, Basidiobolus ranarum, Conidiobolus coronatus, Lagenidium giganteum, Paracoccidioides brasiliensis, and Prototheca wickerhamii), no cross-hybridization of the probe was detected. The specificity of the probe to hybridize to genomic DNA from all isolates of P. insidiosum and not cross-react with DNA from other Pythium species or pathogens that cause symptoms similar to pythiosis in their hosts makes it a powerful tool for the accurate diagnosis of pythiosis. In addition, the probe has the potential for pathological and environmental diagnostic applications.

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A Method for Using Commercial ELISA Tests to Detect Zoospores ofPhytophthoraandPythiumSpecies in Irrigation Water

Cited by 58 publications

References 0 publications

Spatial and Temporal Analysis of the Microbial Community in Slow Sand Filters Used for Treating Horticultural Irrigation Water

Spatial and Temporal Analysis of the Microbial Community in Slow Sand Filters Used for Treating Horticultural Irrigation Water

Detection of Fungal Pathogens in the Environment

Development of a Species-Specific Probe forPythium insidiosumand the Diagnosis of Pythiosis

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