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Milkweed Yellows Phytoplasma
Milkweed yellows phytoplasma is a strain of phytoplasma in the class Mollicutes, a class of bacteria distinguished by the absence of a cell wall. The phytoplasma strain is denoted by the acronym MW1. Like all phytoplasmas, milkweed yellows phytoplasma is an obligate intracellular parasite, that is, it can not live outside of host cells. It spreads by means of an insect vector, the identity of which is unknown. In general, phytoplasmas spread via leafhoppers and other sap-sucking insects that transmit the pathogen from one host plant to another. Taxonomy In 1994, two strains of phytoplasmas that infect the common milkweed ''Asclepias syriaca'' (denoted MW1 and MW2) were shown to be members of the X-disease group (16Sr group III). Milkweed yellows phytoplasma (MW1) was later found to be a ' ''Candidatus'' Phytoplasma pruni'-related strain of phytoplasma belonging to subgroup F (16SrIII-F). Other phytoplasmas in subgroup 16SrIII-F include ''Vaccinium'' witches' broom phy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strain (biology)
In biology, a strain is a genetic variant, a subtype or a culture within a biological species. Strains are often seen as inherently artificial concepts, characterized by a specific intent for genetic isolation. This is most easily observed in microbiology where strains are derived from a single cell colony and are typically quarantined by the physical constraints of a Petri dish. Strains are also commonly referred to within virology, botany, and with rodents used in experimental studies. Microbiology and virology It has been said that "there is no universally accepted definition for the terms 'strain', ' variant', and 'isolate' in the virology community, and most virologists simply copy the usage of terms from others". A strain is a genetic variant or subtype of a microorganism (e.g., a virus, bacterium or fungus). For example, a "flu strain" is a certain biological form of the influenza or "flu" virus. These flu strains are characterized by their differing isoforms of su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Candidatus Phytoplasma Pruni
''Candidatus'' Phytoplasma pruni is a species of phytoplasma in the class Mollicutes, a class of bacteria distinguished by the absence of a cell wall. The specific epithet pruni means "living on ''Prunus''", emphasizing the fact that the phytoplasma is a parasite of various ''Prunus'' species, otherwise known as stone fruits. The phytoplasma is commonly called the X-disease phytoplasma. Like all phytoplasmas, ''Candidatus'' Phytoplasma pruni infects both plants and insects. Potential plant hosts include peach, cherry, plum, and others. Known insect hosts include various species of leafhoppers. Since the pathogen In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ... can not live outside of host cells, it must be transmitted to a new plant host by an infected leafhopper. Taxonomy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacterial Plant Pathogens And Diseases
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of dead bodies; bacteria are responsible for the putrefaction stage in this process. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy. Bacteria also live in symbiotic and parasitic relationsh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grapevine Yellows
Grapevine yellows (GY) are diseases associated to phytoplasmas that occur in many grape growing areas worldwide and are of still increasing significance. The most important grapevine yellows is flavescence dorée. Phytoplasmas are obligate cell wall-less bacterial pathogens (class Mollicutes), and rely on plants and homopterous phloem-sucking insects for biological dispersal. In plants, they are mainly restricted to the phloem tissue where they can move and multiply through the sieve tube elements. Almost identical symptoms of the GY syndrome are caused by different phytoplasmas and appear on leaves, shoots and clusters of grapevine. Typical symptoms include discoloration and necrosis of leaf veins and leaf blades, downward curling of leaves, lack or incomplete lignification of shoots, stunting and necrosis of shoots, abortion of inflorescences and shrivelling of berries. Those symptoms are related to callose deposition at the sieve plates and subsequent degeneration of the phloe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elm Yellows
Elm yellows is a plant disease of elm trees that is spread by leafhoppers or by root grafts."Elm Yellows." Elmcare.Com. 19 Mar. 2008 . Elm yellows, also known as elm phloem necrosis, is very aggressive, with no known cure. Elm yellows occurs in the eastern United States, and southern Ontario in Canada. It is caused by phytoplasmas which infect the phloem (inner bark) of the tree.Price, Terry. "Wilt Diseases." Forestpests.Org. 23 Mar. 2005. 19 Mar. 2008 . Similar phytoplasmas, also known confusingly as 'Elm yellows', also occur in Europe.Conti, M., D'Agostino, G., Mittembergher, L. (1987) A recent epiphytotic of elm yellows in Italy. ''Proceedings of the 7th Congress of the Mediterranean Phytopathological Union'', 208–209. Consejeria de Agricultura y Pesca de la Junta de Andalucia, Granada, Spain Infection and death of the phloem effectively girdles the tree and stops the flow of water and nutrients. The disease affects both wild-growing and cultivated trees. Importance Elms are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aster Yellows
Aster yellows is a chronic, systemic plant disease caused by several bacteria called phytoplasma. The aster yellows phytoplasma (AYP) affects 300 species in 38 families of broad-leaf herbaceous plants, primarily in the aster family, as well as important cereal crops such as wheat and barley. Symptoms are variable and can include phyllody, virescence, chlorosis, stunting, and sterility of flowers. The aster leafhopper vector, ''Macrosteles quadrilineatus'', moves the aster yellows phytoplasma from plant to plant.Davis, M. R. & Raid, R. N., eds. Compendium of Umbelliferous Crop Diseases. St. Paul: The American Phytopathological Society. 2002. pp. 58-59. Its economic burden is primarily felt in the carrot (''Daucus carota'' ssp.'' sativus'') crop industry, as well as the nursery industry. No cure is known for plants infected with aster yellows.Hudelson, Brian. Aster Yellows. University of Wisconsin Garden Facts. 2006. Infected plants should be removed immediately to limit the cont ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catharanthus Roseus
''Catharanthus roseus'', commonly known as bright eyes, Cape periwinkle, graveyard plant, Madagascar periwinkle, old maid, pink periwinkle, rose periwinkle, is a species of flowering plant in the family Apocynaceae. It is native and endemic to Madagascar, but grown elsewhere as an ornamental and medicinal plant. It is a source of the drugs vincristine and vinblastine, used to treat cancer. It was formerly included in the genus ''Vinca'' as ''Vinca rosea''. It has many vernacular names among which are ''arivotaombelona'' or ''rivotambelona'', ''tonga'', ''tongatse'' or ''trongatse'', ''tsimatiririnina'', and ''vonenina''. Synonyms Two varieties are recognized * ''Catharanthus roseus'' var. ''roseus'' : Synonymy for this variety ::''Catharanthus roseus'' var. ''angustus'' Steenis ex Bakhuizen f. :: ''Catharanthus roseus'' var. ''albus'' G.DonG.Don, Gen. Hist. 4(1): 95. 1837. :: ''Catharanthus roseus'' var. ''occellatus'' G.Don :: ''Catharanthus roseus'' var. ''nanus'' Markgr. :: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trillium Grandiflorum
''Trillium grandiflorum'', the white trillium, large-flowered trillium, great white trillium, white wake-robin or french: trille blanc, is a species of flowering plant in the family Melanthiaceae. A monocotyledonous, herbaceous perennial, the plant is native to eastern North America, from northern Quebec to the southern parts of the United States through the Appalachian Mountains into northernmost Georgia and west to Minnesota. There are also several isolated populations in Nova Scotia, Maine, southern Illinois, and Iowa. ''Trillium grandiflorum'' is most common in rich, mixed upland forests. It is easily recognised by its attractive three-petaled white flowers, opening from late spring to early summer, that rise above a whorl of three leaf-like bracts. It is an example of a spring ephemeral, a plant whose life-cycle is synchronised with that of the deciduous woodland which it favours. White trillium often occurs in dense drifts of many individuals. The G. Richard Thompson ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Milkweed
''Asclepias'' is a genus of herbaceous, perennial, flowering plants known as milkweeds, named for their latex, a milky substance containing cardiac glycosides termed cardenolides, exuded where cells are damaged. Most species are toxic to humans and many other species, primarily due to the presence of cardenolides, although, as with many such plants, there are species that feed upon them (e.g. their leaves) and from them (e.g. their nectar). Most notable are monarch butterflies, who use and require certain milkweeds as host plants for their larvae. The genus contains over 200 species distributed broadly across Africa, North America, and South America. It previously belonged to the family Asclepiadaceae, which is now classified as the subfamily Asclepiadoideae of the dogbane family, Apocynaceae. The genus was formally described by Carl Linnaeus in 1753, who named it after Asclepius, the Greek god of healing. Flowers Members of the genus produce some of the most complex flowe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infection
An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable disease, is an illness resulting from an infection. Infections can be caused by a wide range of pathogens, most prominently bacteria and viruses. Hosts can fight infections using their immune system. Mammalian hosts react to infections with an innate response, often involving inflammation, followed by an adaptive response. Specific medications used to treat infections include antibiotics, antivirals, antifungals, antiprotozoals, and antihelminthics. Infectious diseases resulted in 9.2 million deaths in 2013 (about 17% of all deaths). The branch of medicine that focuses on infections is referred to as infectious disease. Types Infections are caused by infectious agents (pathogens) including: * Bacteria (e.g. ''Mycobacterium tuberculosis'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asclepias Syriaca
''Asclepias syriaca'', commonly called common milkweed, butterfly flower, silkweed, silky swallow-wort, and Virginia silkweed, is a species of flowering plant. It is native to southern Canada and much of the United States east of the Rocky Mountains, excluding the drier parts of the prairies. It is in the genus ''Asclepias'', the milkweeds. It grows in sandy soils as well as other kinds of soils in sunny areas. Description ''A. syriaca'' is a clonal perennial plant, perennial forb growing up to tall. Individual plants grow from rhizomes. All parts of common milkweed plants produce a white latex when cut. The simple leaves are opposite, sometimes whorled; broadly glossary of botanical terms#ovate, ovate-glossary of leaf morphology#lanceolate, lanceolate. They grow to long and broad, usually with entire, glossary_of_leaf_morphology#Edge#undulate, undulate margins and reddish main veins. They have very short Petiole (botany), petioles and velvety undersides. The highly fragrant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phytoplasma
Phytoplasmas are obligate intracellular parasites of plant phloem tissue and of the insect vectors that are involved in their plant-to-plant transmission. Phytoplasmas were discovered in 1967 by Japanese scientists who termed them mycoplasma-like organisms. Since their discovery, phytoplasmas have resisted all attempts at ''in vitro'' culture in any cell-free medium; routine cultivation in an artificial medium thus remains a major challenge. Phytoplasmas are characterized by the lack of a cell wall, a pleiomorphic or filamentous shape, a diameter normally less than 1 μm, and a very small genome. Phytoplasmas are pathogens of agriculturally important plants, including coconut, sugarcane, and sandalwood, in which they cause a wide variety of symptoms ranging from mild yellowing to death. Phytoplasmas are most prevalent in tropical and subtropical regions. They are transmitted from plant to plant by vectors (normally sap-sucking insects such as leafhoppers) in which they both sur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
