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Pythium
''Pythium'' is a genus of parasitic oomycetes. They were formerly classified as fungi. Most species are plant parasites, but '' Pythium insidiosum'' is an important pathogen of animals, causing pythiosis. The feet of the fungus gnat are frequently a vector for their transmission. Morphology ;Hyphae: ''Pythium'' species, like others in the family Pythiaceae, are usually characterized by their production of coenocytic hyphae without septations. ;Oogonia: Generally contain a single oospore. ;Antheridia: Contain an elongated and club-shaped antheridium. Ecological importance ''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. Thus there is tremendous interest in genetic host resistance, but no crop has ever developed adequate resistance to ''Pythium''. This disease complex usually involves other pathogens such as '' Phytopht ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pythium (248 24)
''Pythium'' is a genus of parasitic oomycetes. They were formerly classified as fungi. Most species are plant parasites, but '' Pythium insidiosum'' is an important pathogen of animals, causing pythiosis. The feet of the fungus gnat are frequently a vector for their transmission. Morphology ;Hyphae: ''Pythium'' species, like others in the family Pythiaceae, are usually characterized by their production of coenocytic hyphae without septations. ;Oogonia: Generally contain a single oospore. ;Antheridia: Contain an elongated and club-shaped antheridium. Ecological importance ''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. Thus there is tremendous interest in genetic host resistance, but no crop has ever developed adequate resistance to ''Pythium''. This disease complex usually involves other pathogens such as ''Phytophthora'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pythiosis
Pythiosis is a rare and deadly tropical disease caused by the oomycete '' Pythium insidiosum''. Long regarded as being caused by a fungus, the causative agent was not discovered until 1987. It occurs most commonly in horses, dogs, and humans, with isolated cases in other large mammals. The disease is contracted after exposure to stagnant fresh water such as swamps, ponds, lakes, and rice paddies. ''P. insidiosum'' is different from other members of the genus in that human and horse hair, skin, and decaying animal and plant tissue are chemoattractants for its zoospores. Additionally, it is the only member in the genus known to infect mammals, while other members are pathogenic to plants and are responsible for some well-known plant diseases. Epidemiology Pythiosis occurs in areas with mild winters because the organism survives in standing water that does not reach freezing temperatures. In the United States, it is most commonly found in the Southern Gulf states, especially Louisia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pythium Insidiosum
''Pythium insidiosum'' is a species of '' Pythium'' and a member of the class oomycota. ''Pythium insidiosum'' is mainly found in standing water and occasionally soil. Unlike most ''Pythium'' species, which are generally pathogens of terrestrial plants, ''Pythium insidiosum'' is a pathogen of mammals. It causes pythiosis, mainly in horses, dogs, and humans. It can also cause disease in cats. It is a non-transmissible disease and occurs mainly in tropical climate, endemic to Thailand, affecting mainly humans and horses and in Brazil, affecting mainly horses. Infection can occur in healthy mammals. The pathogen is well-adapted to mammalian body temperature, with an optimum temperature for growth of . The cell walls of ''Pythium insidiosum'' are composed of β-glucans and cellulose (compared to the chitin walls of fungi), and their cytoplasmic membranes lack sterol A sterol is any organic compound with a Skeletal formula, skeleton closely related to Cholestanol, cholestan-3 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oomycete
The Oomycetes (), or Oomycota, form a distinct phylogenetic lineage of fungus-like eukaryotic microorganisms within the Stramenopiles. They are filamentous and heterotrophic, and can reproduce both sexually and asexually. Sexual reproduction of an oospore is the result of contact between hyphae of male antheridia and female oogonia; these spores can overwinter and are known as resting spores. Asexual reproduction involves the formation of chlamydospores and sporangia, producing motile zoospores. Oomycetes occupy both saprophytic and pathogenic lifestyles, and include some of the most notorious pathogens of plants, causing devastating diseases such as late blight of potato and sudden oak death. One oomycete, the mycoparasite '' Pythium oligandrum'', is used for biocontrol, attacking plant pathogenic fungi. The oomycetes are also often referred to as water molds (or water moulds), although the water-preferring nature which led to that name is not true of most species, whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Damping Off
Damping off (or damping-off) is a horticultural disease or condition, caused by several different pathogens that kill or weaken seeds or seedlings before or after they germinate. It is most prevalent in wet and cool conditions. Symptoms There are various symptoms associated with damping off; these reflect the variety of different pathogenic organisms which can cause the condition. However, all symptoms result in the death of at least some seedlings in any given population.Buczacki, S., and Harris, K., ''Pests, Diseases and Disorders of Garden Plants'', Collins, 1998, pp. 481–2. Groups of seedlings may die in roughly circular patches, the seedlings sometimes having stem lesions at ground level. Stems of seedlings may also become thin and tough ("wire-stem") resulting in reduced seedling vigor. Leaf spotting sometimes accompanies other symptoms, as does a grey mold growth on stems and leaves. Roots sometimes rot completely or back to just discolored stumps. Causal agents A numbe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pythiaceae
Pythiaceae is a family of oomycetes. The family includes serious plant and animal pathogens in the genus '' Pythium''. The family was circumscribed by German mycologist Joseph Schröter in 1893. Lifecycle *Live on land ( terrestrial), and in water ( aquatic), or a combination of the two (amphibious). *Most are deadly parasites, causing root rot and damping off on plants and pythiosis on animals. *The diploid (2N) life stage predominates, with a short haplophase initiated during sexual reproduction before the fusion of the gametes. Most species are homothallic. Reproduction The sporangia may germinate via a germ tube or by release of motile zoospores, depending on the species and the environmental conditions. Economic importance Some '' Pythium'' species cause "damping off Damping off (or damping-off) is a horticultural disease or condition, caused by several different pathogens that kill or weaken seeds or seedlings before or after they germinate. It is most prevalent in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oospore
An oospore is a thick-walled sexual spore that develops from a fertilized oosphere in some algae, fungi, and oomycetes. They are believed to have evolved either through the fusion of two species or the chemically induced stimulation of mycelia, leading to oospore formation. In Oomycetes, oospores can also result from asexual reproduction, by apomixis In botany, apomixis is asexual development of seed or embryo without fertilization. However, other definitions include replacement of the seed by a plantlet or replacement of the flower by bulbils. Apomictically produced offspring are geneti .... These haploid, non-motile spores are the site of meiosis and karyogamy in oomycetes. A dormant oospore, when observed under an electron microscope, has led researchers to draw conclusion that there is only a single central globule with other storage bodies surrounding it. References {{reflist Reproduction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phytophthora
''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species cause economic losses on crops worldwide, as well as environmental damage in natural ecosystems. The cell wall of ''Phytophthora'' is made up of cellulose. The genus was first described by Heinrich Anton de Bary in 1875. Approximately 210 species have been described, although 100–500 undiscovered ''Phytophthora'' species are estimated to exist. Pathogenicity ''Phytophthora'' spp. are mostly pathogens of dicotyledons, and many are relatively host-specific parasites. '' P. cinnamomi'', though, infects thousands of species ranging from club mosses, ferns, cycads, conifers, grasses, lilies, to members of many dicotyledonous families. Many species of ''Phytophthora'' are plant pathogens of considerable economic importance. '' P. infestans'' was the infective agent of the potato blight that caused the Gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Root Rot
Root rot is a condition in which anoxic conditions in the soil or potting media around the roots of a plant cause them to rot. This occurs due to excessive standing water around the roots.-Hydroponics Root Rot: What is It, How To Treat It, How to Prevent It''Origin Hydroponics.'' June 2, 2018 Root Rot In Your Hydroponic System: 4 Reasons (+ Solutions)''YOUR INDOOR HERBS AND GARDEN. n.d'' Tips For Preventing Root Rot In Hydroponics''Fresh Air With Housplants''. February 3, 2022. It is found in both indoor and outdoor plants, although it is more common in indoor plants due to overwatering, heavy potting media, or containers with poor drainage. The leaves of plants experiencing root rot often yellow and die, and if allowed to continue, the condition can be fatal to the plant. To avoid root rot, it is best to only water plants when the soil becomes dry, and to put the plant in a well-drained pot. Using a dense potting media such as one dug up from outdoors can also cause root ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhizoctonia Solani
''Rhizoctonia solani'' is a species of fungus in the order Cantharellales. Basidiocarps (fruit bodies) are thin, effused, and web-like, but the fungus is more typically encountered in its anamorphic state, as hyphae and sclerotia. The name ''Rhizoctonia solani'' is currently applied to a complex of related species that await further research. In its wide sense, ''Rhizoctonia solani'' is a facultative plant pathogen with a wide host range and worldwide distribution. It causes various plant diseases such as root rot, damping off, and wire stem. It can also form mycorrhizal associations with orchids. Taxonomy In 1858, the German plant pathologist Julius Kühn observed and described a fungus on diseased potato tubers and named it ''Rhizoctonia solani'', the species epithet referring to '' Solanum tuberosum'' (potato). The disease caused was well known before the discovery and description of the fungus. In 1956, Dutch mycologist M.A. Donk published the new name ''Thanatephoru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zoospore
A zoospore is a motile asexual spore that uses a flagellum for locomotion in aqueous or moist environments. Also called a swarm spore, these spores are created by some protists, bacteria, and fungi to propagate themselves. Certain zoospores are infectious and transmittable, such as '' Batrachochytrium dendrobatidis'', a fungal zoospore that causes high rates of mortality in amphibians. Diversity General morphology Zoospores are composed of a microtubular cytoskeleton base which extends from the base of the flagellum. The complexity and structure of this cytoskeleton is variable and is largely dependent on volume and size. One common feature of zoospores is their asymmetrical shape; a result of the ventral grove housing the flagella base. Certain zoospores progress through different phases, the first phase commonly referred to as 'the initial'. Others form cysts that vary tremendously in volume (14-4905 cubic micrometers) and shape, each with distinctive hair structures. Flag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Guelph
The University of Guelph (abbreviated U of G) is a comprehensive Public university, public research university in Guelph, Ontario, Canada. It was established in 1964 after the amalgamation of Ontario Agricultural College (1874), the MacDonald Institute (1903), and the Ontario Veterinary College (1922), and has since grown to an institution of almost 30,000 students (including those at the Humber campus, Ridgetown campus, off-campus degree enrolments, diploma enrolments and part-time students) and employs 830 full-time faculty (academic staff) as of fall 2019. It offers 94 undergraduate degrees, 48 graduate programs, and 6 associate degrees in many different disciplines. The university conducts a significant degree of research and offers a wide range of undergraduate, graduate, and professional degrees. According to the ''Journal of Hospitality & Tourism Research'', the university's Hospitality and Tourism Management program has Canada's highest research index. The faculty at t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
