Quantitative studies on spore production and host infection by Pythium spp by Roger J. Sauve

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Statementby Roger J. Sauve
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Paginationvii, 81 leaves :
Number of Pages81
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Open LibraryOL24359523M
OCLC/WorldCa4803146

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QUANTITATIVE STUDIES ON SPORE PRODUCTION AND HOST INFECTION BY PYTHIUM SPP. by Roger J. Sauve December, Chairman: David J. Mitchell Major Department: Plant Pathology Oospore production by Pythium aphanidermatum, P.

debaryanum, P. myriotylum, and P. polymastum was evaluated on two natural media and on two synthetic media.

Full text of "Quantitative studies on spore production and host infection by Pythium spp." See other formats QUANTITATIVE STUDIES ON SPORE PRODUCTION AND HOST INFECTION BY PYTHIUM SPP.

BY ROGER J. SAUVE A DISSERTATION PRESENTED TO THE GRADUATE COUNCIL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUI REMENTS FOR THE. Quantitative studies on spore production and host infection by Pythium spp.

Sauve, Roger J. Type. Book Material. Published material. Publication info. Notes: Typescript. Vita. Thesis--University of Florida. Subjects. Infection experiments The ability of the Olpidiopsis to infect Pythium and Phytophthora spp. was tested by inoculating the potential hosts growing on plates of CMA with the parasite.

Twenty-six cultures of Pythium spp. and seven of Phythophthora spp. from the Aquatic Phycomycete Culture Collection at Reading University were tested (Table 1).Cited by:   The mechanisms by which these microbial agents suppress diseases caused by Pythium spp., such as interference with pathogen survival, disruption of the process of plant infection, and induced host resistance, are evaluated.

The possibilities for enhancement of efficacy of specific biological control agents by genetic manipulation or deployment Cited by: Whether Si decreases root infection by modifying root surface characteristics and/or spore germination is not known.

Despite the considerable number of studies on the interaction between Si and several species of Pythium, quantitative measurements on the spread of Pythium species at a root level as affected by Si are lacking.

The solarization treatment with the covered CIQA affected the natural population of Fusarium spp and Pythium spp to a depth of cm in a and % respectively, at an average exterior.

Pythium porphyrae (Oomycota), a pathogen causing red rot diseasein Porphyra spp., can at present only be detected when colonizationof the host thallus has already occurred and so it is often too.

Pythium spp. water molds are responsible for annual losses to the industry and threaten the production of highly susceptible crops such as poinsettia, snapdragon, and geranium. Michigan greenhouses were visited in to engage floriculture growers in the project and receive feedback from the industry for the experimental design of this research.

Pythium usually causes a brown rot of root tips and cortex that may progress up the stem. The root cortex will often slough off. Infected plants are stunted (Fig. 4), and lower leaves may turn yellow, curl, and fall severe conditions, entire plants are killed. The disease is most common in poorly drained growing media and may be carried over in growing media or on infected plants.

While not all species of Pythium cause crop losses, some species of Pythium cause significant diseases on several important, mostly herbaceous, crops. They have a broad host range and disease development is highly dependent on environmental conditions.

Some species require, moist and cool conditions (such as Pythium irregulare and P. ultimum) while others are most severe at higher. to those observed in previous studies.

This new technique for the quantification of Pythium spp. is rapid and accurate, and will be a useful tool in the future study of these pathogenic Pythium spp. Pythium root rot is a chronic disease of wheat and barley in eastern Washington.

More than 10 species of Pythium. Spore samplers are widely used in pathogen surveillance but not so much for monitoring the composition of aeromycobiota.

In Canada, a nationwide spore-sampling network (AeroNet) was established as a pilot project to assess fungal community composition in air and rain samples collected using three different spore samplers in the summers of and are induced in other host plants, but this has not been docu-mented on a genome-wide scale.

The present study analyses changes in the lettuce tran-scriptome following inoculation with B. cinerea. Together with Rhizoctonia solani, Sclerotinia spp. and Pythium spp., B. cinerea is one of the main causes responsible for basal rot.

Rhizoctonia solani is a basidiomycete fungus that does not produce any asexual spores (called conidia) and only occasionally will the fungus produce sexual spores (basidiospores). In nature, R. solani reproduces asexually and exists primarily as vegetative mycelium and/or sclerotia. Unlike many basidiomycete fungi, the basidiospores are not.

Inoculation of wild-type Arabidopsis plants with the fungus Alternaria brassicicola results in systemic induction of genes encoding a plant defensin (PDF), a basic chitinase (PR-3), and an acidic hevein-like protein (PR-4). Pathogen-induced induction of these three genes is almost completely abolished in the ethylene-insensitive Arabidopsis mutant ein Pythium-induced root rot is a common crop disease.

When the organism kills newly emerged or emerging seedlings, it is known as damping off, and is a very common problem in fields and greenhouses. This disease complex usually involves other pathogens such as Phytophthora and m wilt is caused by zoospore infection of older plants, leading to biotrophic infections.

Abstract. Members of the genus Pythium interact with plants and microbial members of the rhizosphere using a variety of signaling mechanisms. Biochemical signaling has a role in pathogen–host specificity, host defence response induction, and antagonism between Pythium and biocontrol m irregulare, P.

aphanidermatum, and P. arrhenomanes are among. Phytophthora cinnamomi Rands. is an important root rot pathogen widely distributed in the north hemisphere, with a large host range.

Among others diseases, it is known to be a principal factor in the decline of holm oak and cork oak, the most important tree species in the “dehesa” ecosystem of south-western Spain. Previously, the focus of studies on P.

cinnamomi and holm oak have been on. Microscopic: Very small; can be seen only with the aid/use of a microscope. Penetration: The initial invasion of a host by a pathogen. Primary infection: The first infection of a plant by the overwintering or oversummering pathogen.

Primary inoculum: The overwintering or oversummering pathogen, or its spores that cause primary infection. Burkholderia cepacia AMMDR1 is a biocontrol agent that protects pea and sweet corn seeds from Pythium damping-off in field experiments.

The goal of this work was to understand the effect of B. cepacia AMMDR1 on Pythium aphanidermatum and Aphanomyces euteiches zoospore homing events and on infection of pea seeds or roots.

In vitro, B. cepacia AMMDR1 caused zoospore lysis. SUMMARY Scedosporium spp. are increasingly recognized as causes of resistant life-threatening infections in immunocompromised patients.

Scedosporium spp. also cause a wide spectrum of conditions, including mycetoma, saprobic involvement and colonization of the airways, sinopulmonary infections, extrapulmonary localized infections, and disseminated infections.

This study on the Pyropia-Pythium host pathogen interactions gives a novel understanding into the host defense response, connecting our results with earlier studies on biotic stresses [60, 73]. This investigation of the mechanism of P. yezoensis resistance to P. porphyrae infection will shed more light on defense mechanism in macroalgae.

Root rot, associated with Pythium spp., is a major threat for many agricultural crops (Hendrix and Campbell, ). Pythium aphanidermatum (Edson) has a mainly tropical distribution and is pathogenic to a wide host range (Domsch et al., ).

It infects mainly roots of seedlings or the root tips of older plants (Hendrix and Campbell. Pythium insidiosum, like other Pythium spp, need wet environments to carried out their life cycle in nature. It also can grow in wet soil with grass because its ability to produce resistant spores.

Several investigators have shown that this pathogen requires some plants to complete its life cycle in nature (lily and gramineae (grass).

distinguish Pestalotiaspp. from root decay fungi. Pythiumand Phytophthoraare closely related fungi, and at high concentrations they can cross-react (i.e., Pythiummay cause a positive reaction on a Phytophthora kit, and vice versa).

In fact, a few Pythium species do not react at all with the Pythium kit and react only with the Phytophthorakit. ), antibiosis and production of cell-wall degrading enzymes (El-Tarabily ), siderophore-mediated competition for iron (Matthijs et al. ) and induction of systemic resistance in the host plant (Nakkeeran et al.

) have all been proposed as mechanisms by which rhizosphere biocontrol agents are able to suppress Pythium spp. Phytophthora blight caused by Phytophthora cajani is an emerging disease of pigeonpea (Cajanus cajan L.) affecting the crop irrespective of cropping system, cultivar grown and soil types.

Current detection and identification methods for Phytophthora species rely primarily on cultural and morphological characteristics, the assessment of which is time-consuming and not always suitable. For example, graminicolous Pythium spp.

showed fold more encystment on grass than on dicot roots (P = 0 ) when compared with the broad-host-range Pythium spp.; the corresponding difference for total accumulation (swimming plus encysted spores) was 1 6-fold (P = 0 ). However, such differences could be ecologically meaningful.

Study system. Podosphaera plantaginis is a specialist obligate fungal pathogen which causes powdery mildew symptoms on Pl. haera plantaginis grows on the above‐ground tissues of its host as radial lesions of hyphae that support chains of asexual spores (conidia). Mature conidia are wind‐dispersed to neighbouring plants where they instigate fresh.

Since in the United Kingdom, infections caused by spore-forming bacteria have been associated with increasing illness and death among persons who inject drugs (PWID).

To assess temporal and geographic trends in these illnesses (botulism, tetanus, Clostridium novyi infection, and anthrax), we compared rates across England and Scotland for – Soil‐borne Actinoplanes spp.

have been reported to parasitize oospores of Phytophthora megasperma glycinea (Sutherland and Lockwood ) and Pythium spp. (Khan et al. ; El‐Tarabily et al. ) in in vitro studies. In addition, Actinoplanes spp. have been used in greenhouse experiments to control soil‐borne plant pathogens such.

see that the properties Of a spore tell us' much about the biology and ecology of a fungus. (d) (h) (g) (a) (b) (c) Fig. Examples of tetraradiate, multiple-armed and sigmoid spores found in fast-flowing freshwater streams.

Approximate spore lengths are shown in parentheses. (a) A single conidium of Dendrospora (— pm); (b) conidium. PLANTS CAN ATTRACT UNWANTED GUESTS. Oomycetes employ several types of spores for dissemination and host infection (Box 1).

These include both asexual and sexual spores (McCarren et al., ; Granke et al., ).Colonization by the majority of oomycetes begins when an asexual sporangium releases zoospores, which encyst and form a germ tube ().As discussed below, many aspects of spore.

Pythium spp. can cause disease individually, but frequently several species are isolated from a single plant. For example, P. irregulare can cause root rot on corn and may provide infection courts for other corn pathogens to colonize tissues later in the season (11). In addition, Pythium spp.

recovered from. Objective 2) The ergot fungus only infects unfertilized flowers, so ascospore production by the fungus must coincide with the flowering of susceptible grass hosts in order for infection to occur.

In some years the timing of spore release and host anthesis does not coincide, resulting in little to no ergot. The influence exerted by nonpathogenic Fusarium oxysporum strain Fo47 in triggering cucumber protection against infection by Pythium ultimum was investigated ultrastructurally.

Macroscopic and microscopic observations of the pathogen colony in dual cultures revealed that reduction of Pythium growth was associated with marked disorders.

Number of results to display per page. 20 per page. 20 per page; 50 per page; per page; Search Results. Aims: The aims are to establish a polymerase chain reaction (PCR)‐based method for detecting Pythium myriotylum in the rhizome of ginger and diagnosing ginger soft rot and screening health seed ginger.

Methods and Results: A booster PCR method was established for detection of P. myriotylum using a specific primer selected from rDNA ITS1 region coupled with universal primer ITS2. Seedling and root rots caused by Fusarium spp., Pythium spp. and in some areas Phytophthora sojae were less important as diseases of soybean in than in This was the result of more favorable weather conditions, more rapid soil warmup and less precipitation, for germination and emergence during spring and early summer.

Replant disease is a widespread problem in intensive tree fruit and nut growing areas. It is characterized by reduced productivity in fields repeatedly planted to the same or closely related tree fruit or nut crops. It can also occur in tree fruit and nut nurseries.

In a fruit-bearing orchard the disease can cost growers more than $70, to $an acre due to reduced productivity during. Pythium group F is characterized by filamentous non-inflated sporangia (82, ). Each of the species is able to produce oospores (thick-walled sexual spores) in infected roots and in the rhizosphere.

These Pythium spp. each attack a wide range of host plants.Achievements Dr. Gossen has initiated and led studies that have attracted over $3 M in research grants, and has co-operated in projects totalling an additional $11 M.

He is the author/co-author of more than papers in scientific journals (> since ), 2 books, 15 book chapters, and hundreds of minor scientific publications, abstracts.

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