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Carrot Yellow Leaf Virus
Summary Host The carrot yellow-leaf virus (CYLV) infects carrots, particularly the carrot root cells. There are viruses that are similar to CYLV which affect hogweed and beet roots as well.Adams, I. P., Skelton, A., Macarthur, R., Hodges, T., Hinds, H., Flint, L., Nath, P. D., Boonham, N., & Fox, A. (2014). Carrot yellow leaf virus is associated with carrot internal necrosis. PLOS ONE, 9(11), 1-10. Major patterns of infection There have been sporadic plague (disease), plagues of CYLV occurring in many countries across the world, most notably the United Kingdom, Germany, and Japan. Aphids are the main form of transmission. These insects spread the virus from one carrot patch to another. Once the virus infects the carrot, necrosis starts in the roots. Historical perspectives Discovery The carrot yellow-leaf virus was first isolated in Japanese carrots that had yellowing leaves. Using electron microscopy, the virus particle was found to be 1.6006 X 1012 nm long with a 3.7-nm helic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carrots
The carrot (''Daucus carota'' subsp. ''sativus'') is a root vegetable, typically orange in color, though purple, black, red, white, and yellow cultivars exist, all of which are domesticated forms of the wild carrot, ''Daucus carota'', native to Europe and Southwestern Asia. The plant probably originated in Persia and was originally cultivated for its leaves and seeds. The most commonly eaten part of the plant is the taproot, although the stems and leaves are also eaten. The domestic carrot has been selectively bred for its enlarged, more palatable, less woody-textured taproot. The carrot is a biennial plant in the umbellifer family, Apiaceae. At first, it grows a rosette of leaves while building up the enlarged taproot. Fast-growing cultivars mature within three months (90 days) of sowing the seed, while slower-maturing cultivars need a month longer (120 days). The roots contain high quantities of alpha- and beta-carotene, and are a good source of vitamin A, vitamin K, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RNAi
RNA interference (RNAi) is a biological process in which RNA molecules are involved in sequence-specific suppression of gene expression by double-stranded RNA, through translational or transcriptional repression. Historically, RNAi was known by other names, including ''co-suppression'', ''post-transcriptional gene silencing'' (PTGS), and ''quelling''. The detailed study of each of these seemingly different processes elucidated that the identity of these phenomena were all actually RNAi. Andrew Fire and Craig C. Mello shared the 2006 Nobel Prize in Physiology or Medicine for their work on RNAi in the nematode worm ''Caenorhabditis elegans'', which they published in 1998. Since the discovery of RNAi and its regulatory potentials, it has become evident that RNAi has immense potential in suppression of desired genes. RNAi is now known as precise, efficient, stable and better than antisense therapy for gene suppression. Antisense RNA produced intracellularly by an expression vector ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molting
In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body (often, but not always, an outer layer or covering), either at specific times of the year, or at specific points in its life cycle. In medieval times it was also known as "mewing" (from the French verb "muer", to moult), a term that lives on in the name of Britain's Royal Mews where the King's hawks used to be kept during moulting time before becoming horse stables after Tudor times. Moulting can involve shedding the epidermis (skin), pelage (hair, feathers, fur, wool), or other external layer. In some groups, other body parts may be shed, for example, the entire exoskeleton in arthropods, including the wings in some insects. Examples In birds In birds, moulting is the periodic replacement of feathers by shedding old feathers while producing new ones. Feathers are ... [...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] |
Sternorrhyncha
The Sternorrhyncha suborder of the Hemiptera contains the aphids, whiteflies, and scale insects, groups which were traditionally included in the now-obsolete order "Homoptera". "Sternorrhyncha" refers to the rearward position of the mouthparts relative to the head. Distributed worldwide, all members of this group are plant-feeders, many considered pests feeding on major crops and ornamental plants. Many exhibit modified morphology and/or life cycles, including phenomena such as flightless morphs, parthenogenesis, sexual dimorphism, and eusociality. Phylogeny The phylogeny of the extant Sternorrhyncha, inferred from analysis of small subunit (18S) ribosomal RNA, is shown in the cladogram. The evolutionary position of several fossil taxa are unclear. A suggested phylogeny is: Groups Well-known groups in the Sternorrhyncha include: * aphids – (Aphididae) * woolly and gall-making aphids (Eriosomatinae) * pine and spruce aphids (Adelgidae) * phylloxerans (Phylloxeridae, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homoptera
Homoptera is a suborder of order Hemiptera that is considered by some taxonomists to be paraphyly, paraphyletic, and therefore Deprecation, deprecated (obsolete). It was therefore split into the suborders Sternorrhyncha, Auchenorrhyncha, and Coleorrhyncha. The earlier work was based on nuclear DNA, but more recent phylogenetic analysis using mitochondrial DNA suggest that Homoptera may be a monophyletic group after all, a sister group of Heteroptera. The cause of the disparity in the analyses is suggested to be the long branch attraction effect in phylogenetic analysis, due to rapidly evolving DNA regions. The Homoptera include the aphids, scale insects, cicadas, and leafhoppers, which all have sucking mouthparts. References Insect suborders Hemiptera {{Hemiptera-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aphids
Aphids are small sap-sucking insects and members of the superfamily Aphidoidea. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The group includes the fluffy white woolly aphids. A typical life cycle involves flightless females giving live birth to female nymphs—who may also be already pregnant, an adaptation scientists call telescoping generations—without the involvement of males. Maturing rapidly, females breed profusely so that the number of these insects multiplies quickly. Winged females may develop later in the season, allowing the insects to colonize new plants. In temperate regions, a phase of sexual reproduction occurs in the autumn, with the insects often overwintering as eggs. The life cycle of some species involves an alternation between two species of host plants, for example between an annual crop and a woody plant. Some species feed on only one type of plant, while others are generalists, coloni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pirimicarb
Pirimicarb is a selective carbamate insecticide used to control aphids on vegetable, cereal and orchard crops by inhibiting acetylcholinesterase activity but does not affect useful predators such as ladybirds that eat them. It was originally developed by Imperial Chemical Industries Ltd., now Syngenta, at their Jealott's Hill Jealott's Hill is a village in the county of Berkshire, England, within the civil parish of Warfield. The settlement is on the A3095 road approximately north of Bracknell. The nearest railway station is in . The name of the hill is reported to ... site and first marketed in 1969, four years after its discovery. References External links * Acetylcholinesterase inhibitors Carbamate insecticides Aminopyrimidines Aromatic carbamates {{organic-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Imidacloprid
Imidacloprid is a systemic insecticide belonging to a class of chemicals called the neonicotinoids which act on the central nervous system of insects. The chemical works by interfering with the transmission of stimuli in the insect nervous system. Specifically, it causes a blockage of the nicotinergic neuronal pathway. By blocking nicotinic acetylcholine receptors, imidacloprid prevents acetylcholine from transmitting impulses between nerves, resulting in the insect's paralysis and eventual death. It is effective on contact and via stomach action. Because imidacloprid binds much more strongly to insect neuron receptors than to mammal neuron receptors, this insecticide is more toxic to insects than to mammals. From 1999 through , imidacloprid was the most widely used insecticide in the world. Although it is now off patent, the primary manufacturer of this chemical is Bayer CropScience (part of Bayer AG). It is sold under many names for many uses; it can be applied by soil injection ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
