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Wheat Yellow Leaf Virus
Wheat yellow leaf virus (WYLV) is a wheat (''Triticum'' spp. L.), barley (''Hordeum vulgare'' L.), rye (''Secale cereale'' M.Bieb.), and oat (''Avena sativa'' L.) pathogenic virus of the family ''Closteroviridae''. WYLV virions are 1600–1850 nm in length and 10 nm in diameter. The virus, like other members of its genus, is transmitted by aphids. Identified vectors include ''Rhopalosiphum padi'' L. and '' R. maidis'' Fitch. ( Aphididae). The virus has been identified in crop plants in Japan, China, and Italy. Native host plants include Italian ryegrass ('' Festuca perennis'' Lam.) in Europe and ''Agropyron tsukushiense'' var. ''transiens'' Ohwi in Japan. The virus proliferates in the phloem of its host plants, interfering with the plant's ability to produce sufficient chlorophyll Chlorophyll (also chlorophyl) is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Greek words , ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wheat
Wheat is a grass widely cultivated for its seed, a cereal grain that is a worldwide staple food. The many species of wheat together make up the genus ''Triticum'' ; the most widely grown is common wheat (''T. aestivum''). The archaeological record suggests that wheat was first cultivated in the regions of the Fertile Crescent around 9600 BCE. Botanically, the wheat kernel is a type of fruit called a caryopsis. Wheat is grown on more land area than any other food crop (, 2014). World trade in wheat is greater than for all other crops combined. In 2020, world production of wheat was , making it the second most-produced cereal after maize. Since 1960, world production of wheat and other grain crops has tripled and is expected to grow further through the middle of the 21st century. Global demand for wheat is increasing due to the unique viscoelastic and adhesive properties of gluten proteins, which facilitate the production of processed foods, whose consumption is inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barley
Barley (''Hordeum vulgare''), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains, particularly in Eurasia as early as 10,000 years ago. Globally 70% of barley production is used as animal fodder, while 30% as a source of fermentable material for beer and certain distilled beverages, and as a component of various foods. It is used in soups and stews, and in barley bread of various cultures. Barley grains are commonly made into malt in a traditional and ancient method of preparation. In 2017, barley was ranked fourth among grains in quantity produced () behind maize, rice and wheat. Etymology The Old English word for barley was ', which traces back to Proto-Indo-European and is cognate to the Latin word ' "flour" (''see corresponding entries''). The direct ancestor of modern English ''barley'' in Old English was the derived adjective ''bærlic'', meaning "of barley". The first citation of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Closteroviridae
''Closteroviridae'' is a family of viruses. Plants serve as natural hosts. There are four genera and 59 species in this family, seven of which are unassigned to a genus. Diseases associated with this family include: yellowing and necrosis, particularly affecting the phloem. Taxonomy Genome type and transmission vector are two of the most important traits used for classification. Ampeloviruses and Closteroviruses have monopartite genomes and are transmitted by pseudococcid mealybugs (and soft scale insects) and aphids respectively. While Criniviruses are bipartite and transmitted by whiteflies Whiteflies are Hemipterans that typically feed on the undersides of plant leaves. They comprise the family Aleyrodidae, the only family in the superfamily Aleyrodoidea. More than 1550 species have been described. Description and taxonomy The .... Genera: * '' Ampelovirus'' * '' Closterovirus'' * '' Crinivirus'' * '' Velarivirus'' Unassigned species: * '' Actinidia virus 1'' * ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vector (epidemiology)
In epidemiology, a disease vector is any living agent that carries and transmits an infectious pathogen to another living organism; agents regarded as vectors are organisms, such as parasites or microbes. The first major discovery of a disease vector came from Ronald Ross in 1897, who discovered the malaria pathogen when he dissected a mosquito. Arthropods Arthropods form a major group of pathogen vectors with mosquitoes, flies, sand flies, lice, fleas, ticks, and mites transmitting a huge number of pathogens. Many such vectors are haematophagous, which feed on blood at some or all stages of their lives. When the insects feed on blood, the pathogen enters the blood stream of the host. This can happen in different ways. The ''Anopheles'' mosquito, a vector for malaria, filariasis, and various arthropod-borne-viruses (arboviruses), inserts its delicate mouthpart under the skin and feeds on its host's blood. The parasites the mosquito carries are usually located in its salivary gla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhopalosiphum Padi
Bird cherry-oat aphid (''Rhopalosiphum padi'') is an aphid in the superfamily Aphidoidea in the order Hemiptera. It is a true bug and sucks sap from plants. It is considered a major pest in cereal crops, especially in temperate regions, as well as other hosts in parts of Northern Europe. It is the principal vector of many viruses in economically important field crops. Host plants and distribution ''R. padi'' has a worldwide distribution and according to research, they can colonize a number of dicotyledon host plants, although their preference is within monocotyledon plant groups much like the closely related '' R. maidis'' and '' R. rufiabdominale''. The main plant hosts are categorized and listed below but as the name suggests, the primary host is '' Prunus padus'', where it overwinters as eggs. In Northern America, it is found to overwinter on ''Prunus virginiana'' (common choke-cherry). In spring, it attacks all major cereals and pasture grasses; particularly barley, oats, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhopalosiphum Maidis
''Rhopalosiphum maidis'', common names corn leaf aphid and corn aphid, is an insect, and a pest of maize and other crops. It has a nearly worldwide distribution and is typically found in agricultural fields, grasslands, and forest-grassland zones. Among aphids that feed on maize, it is the most commonly encountered and most economically damaging, particularly in tropical and warmer temperate areas. In addition to maize, ''R. maidis'' damages rice, sorghum, and other cultivated and wild monocots. Description The bodies of wingless parthenogenetic females are green or whitish-green. The head, antennae, legs, cornicles, tail, and transverse bands on the abdomen are black-brown. The body has sparse short hairs. The length of the antennae is less than half the length of the body. Cornicles are not longer than the finger-like tail. In winged females, the head and thoracic section are black-brown and the cornicles are shorter than in the wingless females. Most ''R. maidis'' po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aphididae
The Aphididae are a very large insect family in the aphid superfamily ( Aphidoidea), of the order Hemiptera. These insects suck the sap from plant leaves. Several thousand species are placed in this family, many of which are considered plant/crop pests. They are the family of insects containing most plant virus vectors (around 200 known) with the green peach aphid (''Myzus persicae'') being one of the most prevalent and indiscriminate carriers. Evolution Aphids originated in the late Cretaceous about (Mya), but the Aphidinae which comprises about half of the 4700 described species and genera of aphids alive today come from their most recent radiation which occurred in the late Tertiary less than 10 Mya.Von Dohlen CD, Moran NA (2000) Molecular data support a rapid radiation of aphids in the Cretaceous and multiple origins of host alternation. Biol J Linnean Soc 71: 689–717Von Dohlen CD, Rowe CA, Heie OE (2006) A test of morphological hypotheses for tribal and subtribal relatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Festuca Perennis
''Lolium perenne'', common name perennial ryegrass, English ryegrass, winter ryegrass, or ray grass, is a grass from the family Poaceae. It is native to Europe, Asia and northern Africa, but is widely cultivated and naturalised around the world. Description The plant is a low-growing, tufted, hairless grass, with a bunching (or tillering) growth habit. The leaves are dark green, smooth and glossy on the lower surface, with untoothed parallel sides and prominent parallel veins on the upper surface. The leaves are folded lengthwise in bud (unlike the rolled leaves of Italian ryegrass, ''Lolium multiflorum'') with a strong central keel, giving a flattened appearance. The ligule is very short and truncated and often difficult to see. The small white auricles grip the stem at the base of the leaf blade. Leaf sheaths at the base are usually tinged pink and hairless. Stems grow up to 90 cm. The inflorescence is unbranched, with spikelets on alternating sides edgeways-on to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agropyron Tsukushiense Var
''Agropyron'' is a genus of Eurasian plants in the grass family), native to Europe and Asia but widely naturalized in North America. Species in the genus are commonly referred to as wheatgrass. ; Species * ''Agropyron badamense'' - Tajikistan, Kyrgyzstan, Uzbekistan, Kazakhstan * ''Agropyron bulbosum'' - Iran * ''Agropyron cimmericum'' - Ukraine, Crimea * '' Agropyron cristatum'' - Crested wheatgrass - Eurasia + North Africa from Spain + Morocco to Korea + Khabarovsk; naturalized in western + central North America (United States, Canada, northern Mexico) * ''Agropyron dasyanthum'' - Ukraine * '' Agropyron desertorum'' - Desert Wheatgrass - from Crimea + Caucasus to Mongolia + Siberia * '' Agropyron deweyi'' - Turkey * ''Agropyron fragile'' - Siberian wheatgrass - from Caucasus to Mongolia; naturalized in scattered locales in western United States + Canada * ''Agropyron michnoi'' - Buryatiya, Zabaykalsky Krai, Mongolia, Inner Mongolia * ''Agropyron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phloem
Phloem (, ) is the living biological tissue, tissue in vascular plants that transports the soluble organic compounds made during photosynthesis and known as ''photosynthates'', in particular the sugar sucrose, to the rest of the plant. This transport process is called translocation. In trees, the phloem is the innermost layer of the bark (botany), bark, hence the name, derived from the Ancient Greek word (''phloiós''), meaning "bark". The term was introduced by Carl Nägeli in 1858. Structure Phloem tissue consists of conducting Cell (biology), cells, generally called sieve elements, Ground tissue#Parenchyma, parenchyma cells, including both specialized companion cells or albuminous cells and unspecialized cells and supportive cells, such as fibres and sclereids. Conducting cells (sieve elements) Sieve elements are the type of cell that are responsible for transporting sugars throughout the plant. At maturity they lack a Cell nucleus, nucleus and have very few organelles, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorophyll
Chlorophyll (also chlorophyl) is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Greek words , ("pale green") and , ("leaf"). Chlorophyll allow plants to absorb energy from light. Chlorophylls absorb light most strongly in the blue portion of the electromagnetic spectrum as well as the red portion. Conversely, it is a poor absorber of green and near-green portions of the spectrum. Hence chlorophyll-containing tissues appear green because green light, diffusively reflected by structures like cell walls, is less absorbed. Two types of chlorophyll exist in the photosystems of green plants: chlorophyll ''a'' and ''b''. History Chlorophyll was first isolated and named by Joseph Bienaimé Caventou and Pierre Joseph Pelletier in 1817. The presence of magnesium in chlorophyll was discovered in 1906, and was that element's first detection in living tissue. After initial work done by German chemi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
