Control Of Plant Virus Diseases. Author by : F. C. Bawden. Languange : en. Publisher by : Daya Books. Format Available : PDF, e. Pub, Mobi. Total Read : 1. Total Download : 4. File Size : 4. 4,5 Mb. Description : The Subject Of Plant Viruses And Virus Diseases Are Receiving Increasing Attention At The Hands Of Research Scholars Such As Chemists, Crystallographers, Entomologists, Geneticists, Serologists, Physicists Etc. They Are Able To Bring Fresh Techniques To The Subject. The Book Is An Attempt To Describe And Correlate The Advances That Have Been Made So Far In The Study Of Plant Viruses, And Virus Diseases. During The Past Few Years, Many New Virus Diseases Have Been Described, Some Of Great Economic Importance And Some With Novel Kinds Of Symptoms; Much Has Been Done On The Factors That Affect Spread; And Insect Vectors Have Been Identified In Species Of Insects Previously Not Incriminated. More Viruses Have Been Purified And Their Chemical Constitution Has Been Further Elucidated, And The Advances In Electron Microscopy Have Provided Much Information On Their Morphology. Pdf Virus RemovalAll These Developments Have Been Incorporated In The Book. The Book Is A Treasure For Agriculture And Horticulture Departments And All Those Interested In These Subjects. Contents Chapter 1: Introduction; Definition Of Subject, Economic Importance, Historical, Views On The Nature Of Viruses, Nomenclature, Chapter 2: External Symptoms Of Infected Plants; Range Of Host Plant Reactions, Type Diseases, Virus Strains, Effects Of Environment On Symptoms, Chapter 3: Internal Symptoms Of Infected Plants; Intracellular Inclusions Formed By Tobacco Mosaic Viruses, Possible Relationship Between Tobacco Mosaic Viruses And The Intracellular Inclusions, Intracellular Inclusions Caused By Viruses Other Than Tobacco Mosaic, Internal Changes Other Than Intracellular Inclusions, Chapter 4: Methods Of Transmission; Grafting And The Use Of Dodder, Inoculation With Plant Extracts, Transmission By Insects, Seed Borne Viruses, Soil Borne Viruses, Chapter 5: The Relations Between Viruses And Their Vectors; Viruses Which Persist In Their Insect Vectors, Latent Period And Virus Multiplication In Vectors, Viruses Whose Vectors Soon Lose Infectivity, Effect Of The Number Of Insects In Transmitting, Chapter 6: Mutation, Interference Between Strains, And Recovery From Disease; Kinds Of Variation, Origin Of Variation, Acquired Immunity, Chapter 7: Serological Reactions Of Plant Viruses; Preparation Of Antisera, Methods Of Testing, The Antigenicity Of Plant Viruses, Neutralisation Of Infectivity, Specificity Of Serological Reactions, Effect Of Particle Shape Of Serological Reactions, Chapter 8: Quantitative Methods Of Assaying For Viruses; The Use Of Local Lesions, Starch Iodine Lesions, The Use Of Preciptin Tests, Chapter 9: The Purification Of Viruses; Treatment Of Plants, Tobacco Mosaic And Other Anisometric Viruses, Tomato Bushy Stunt And Other Crystalline Viruses, High Speed Centrifugation, Activity Of Purifie Preparations, Proteins From Healthy Plants, Chapter 1. Chemical And Physical Properties Of Purified Virus Preparations; Elementary Composition, Isolation And Properties Of Nucleic Acid, The Denatured Protein, Specific Volume And Hydration, Precipitation And Isoelectric Points, Chapter 1. The Crystallinity Of Plant Viruses; Optical Properties Of Crystals, Anistropy Of Flow And The Layering Phenomenon, Crystal And Liquid Crystals, Chapter 1. PDF File : Seed Borne Plant Virus Diseases By K Subramanya Sastry 2013 01 04 Page : 1. Plant Virus Vs Animal VirusTOMATO, EGGPLANT & PEPPER DISEASES. Xanthomonas Corynespora Tobacco/Tomato mosaic virus. Common Plant Diseases and Pests 0 What is plant disease? 0 Late Blight of tomato and potato 0 Other Common Diseases of Vegetables and Ornamentals. Texas Plant Disease Handbook. Common Diseases of Tomatoes. OSU Extension Agents’ Handbook of Insect, Plant Disease. Several different virus diseases. Virus Diseases Common Mosaic. This HANDBOOK OF BEAN DISEASES is published to pro-. It can survive in plant debris for 1 year. Download and Read Plant Virus And Viroid Diseases In The Tropics. The Estimation Of Particle Sizes; Filtration, Sedimentation And Diffusion, Microscopy And X- Ray Diffraction, Additional Methods, The Aggregation Of Anisometric Viruses, Chapter 1. Types Of Inactivation; Inhibition Of Infectivity, Inactivation Without Lossof Serological Activity, Inactivation And Denaturation, Chapter 1. Taxonomy Of Viruses; Nomenclature And Classification, The Grouping Of Virus Strains, The Formation Of Larger Groups, Chapter 1. Virus Diseases And Host Plant Physiology; Host Plant Metabolism And Susceptibility, Effects Of Viruses On Host Plant Metabolism, The Movement Of Viruses, Chapter 1. Control Measures Against Virus Diseases; Curative Treatments, General Measures, Insect Borne Viruses, Viruses Transmitted Mechanically, Chapter 1. Speculations On The Origins Of Viruses. ![]() ![]() Introduction to plant viruses. What are viruses? Why are viruses important? How are viruses transmitted? How are viruses classified? Read a Belorussian translation of this page. ![]() What are viruses? Viruses are very small (submicroscopic) infectious particles (virions) composed of a protein coat and a nucleic acid core. They carry genetic information encoded in their nucleic acid, which typically specifies two or more proteins. Translation of the genome (to produce proteins) or transcription and replication (to produce more nucleic acid) takes place within the host cell and uses some of the host's biochemical . Viruses do not capture or store free energy and are not functionally active outside their host. They are therefore parasites (and usually pathogens) but are not usually regarded as genuine microorganisms. Some infect bacteria, and are known as bacteriophages, whereas others are known that infect algae, protozoa, fungi (mycoviruses), invertebrates, vertebrates or vascular plants. However, some viruses that are transmitted between vertebrate or plant hosts by feeding insects (vectors) can replicate within both their host and their vector. This web site is mostly concerned with those viruses that infect plants but we also provide some taxonomic and genome information about viruses of fungi, protozoa, vertebrates and invertebrates where these are related to plant viruses. Their genomes are much smaller than those of viruses (up to 4. RNA) and do not code for any proteins. Amongst the human viruses, smallpox, polio, influenza, hepatitis, human immunodeficiency virus (HIV- AIDS), measles and the SARS coronavirus are particularly well known. While antibiotics can be very effective against diseases caused by bacteria, these treatments are ineffective against viruses and most control measures rely on vaccines (antibodies raised against some component of the virus) or relief of the symptoms to encourage the body's own defense system. Infected plants may show a range of symptoms depending on the disease but often there is leaf yellowing (either of the whole leaf or in a pattern of stripes or blotches), leaf distortion (e. Sometimes the virus is restricted to certain parts of the plant (e. Infection does not always result in visible symptoms (as witnessed by names such as Carnation latent virus and Lily symptomless virus, both members of the genus Carlavirus). Occasionally, virus infection can result in symptoms of ornamental value, such as 'breaking' of tulips or variegation of Abutilon. The major means of control (depending on the disease) include. Chemical or biological control of the vector (the organism transmitting the disease, often an insect): this can be very effective where the vectors need to feed for some time on a crop before the virus is transmitted but are of much less value where transmission occurs very rapidly and may already have taken place before the vector succumbs to the pesticide. However, no such . Transgenic resistance has shown considerable promise for many plant- virus combinations following the discovery that the incorporation of part of the virus genome into the host plant may confer a substantial degree of resistance. For example, the use of this approach in Hawaii to control Papaya ringspot virus has been credited with saving the local papaya industry. However, this technology is controversial, particularly in Europe, and the extent to which it will be used commercially is currently uncertain. This is a major objective of plant quarantine procedures throughout the world as well as more local schemes. The viruses have the . Most plant viruses are therefore transmitted by a vector organism that feeds on the plant or (in some diseases) are introduced through wounds made, for example, during cultural operations (e. Barley stripe mosaic virus, genus Hordeivirus) while many that cause systemic infections accumulate in vegetatively- propagated crops. The major vectors of plant viruses are. Insects. This forms the largest and most significant vector group and particularly includes. Aphids: transmit viruses from many different genera, including Potyvirus, Cucumovirus and Luteovirus. The picture shows the green peach aphid Myzus persicae, the vector of many plant viruses, including Potato virus Y. The picture shows Bemisia tabaci, the vector of many viruses including Tomato yellow leaf curl virus and Lettuce infectious yellows virus. Hoppers: transmit viruses from several genera, including those in the families Rhabdoviridae and Reoviridae. The picture shows Micrutalis malleifera, the treehopper vector of Tomato pseudo- curly top virus. Thrips: transmit viruses in the genus Tospovirus. The picture shows Frankinella occidentalis, the western flower thrips that is a major vector of Tomato spotted wilt virus. Beetles: transmit viruses from several genera, including Comovirus and Sobemovirus. The virus- vector relationships are of several types. At one extreme, the association occurs within the feeding apparatus of the insect, where the virus can be rapidly adsorbed and then released into a different plant cell.The feeding insect looses the virus rapidly when feeding on a non- infected plant. World Creator 25 Isometric Iso 2D 3D Game Graphics Tiles . Such a relationship is termed .The best studied examples are of potyvirus transmission by aphids.The vector needs to feed on an infected plant for much longer and there is an interval (perhaps several hours) before it can transmit. Once it becomes viruliferous, the vector will remain so for many days and such a relationship is therefore termed . The best studied examples are of luteovirus transmission by aphids. In some examples of this type (e. The picture shows an adult female of Paratrichodorus pachydermus, the vector of Tobacco rattle virus. Plasmodiophorids: these are root- infecting obligate parasites traditionally regarded as fungi but now known to be more closely related to protists. They transmit viruses in the genera Benyvirus, Bymovirus, Furovirus, Pecluvirus and Pomovirus. The picture shows Polymyxa graminis, the vector of several cereal viruses including Barley yellow mosaic virus, growing within a barley root cell. Mites: these transmit viruses in the genera Rymovirus and Tritimovirus. The picture shows Aceria tosichella, the vector of Wheat streak mosaic virus. It includes those viruses with the largest known genomes (up to about 4. Well- known viruses in this group include the herpes and pox viruses. The group includes the retroviruses, of which Human immunodeficiency virus (HIV), the cause of AIDS, is a member. There is a single family of plant viruses in this group and this is characterised by a single component of circular ds. DNA, the replication of which is via an RNA intermediate. There are some plant viruses in this group and it also includes the viruses that cause measles, influenza and rabies. It also includes the SARS coronavirus and many other viruses that cause respiratory diseases (including the . Typically, a combination of characters are used and some of the most important are. Particle morphology: the shape and size of particles as seen under the electron microscope. Where genome sequences have been determined, the relatedness of different sequences is often an important factor in discriminating between species. Individual components vary in size from about 1kb (Nanovirus components) to about 2. Closterovirus). Most plant viruses have at least 3 genes: 1 (or more) concerned with replication of the nucleic acid, 1 (or more) concerned with cell- to- cell movement of the virus and 1 (or more) encoding a structural protein that is assembled into the virus particle (usually called the . There may also be additional genes that have a regulatory function or which are required for transmission between plants (association with a vector). These are summarised for each genus in the genus description pages but 3 examples here serve to illustrate some of the variety. Genus Potyvirus: in this very large genus, there is one ss. RNA component that encodes one large (c. Da) polyprotein. This is cleaved by 3 different proteases (all encoded by the virus itself) into 1. The two proteins at the C- terminus of the polyprotein are respectively an RNA- dependent RNA polymerase (NIb, involved in replication of the virus) and the (single) coat protein (CP). Mobile 9 Nokia 5233 Gta Games . Many of the proteins have multiple functions.The genome organisation of a typical member is shown here, indicating the 1.Genus Furovirus: in this genus there are two ss. RNA components. The 5'- proximal gene on each RNA is translated directly from the genomic RNA: on RNA1 (the larger RNA component) this gene encodes a replication protein and on RNA2 it is the coat protein. The stop codons of both of these genes are . On RNA1, the replication protein is extended to include an RNA- dependent RNA polymerase (Rd. Rp) while the readthrough region of the coat protein is probably required for particle assembly and for transmission by the plasmodiophorid vector. There is a further (3'- proximal) gene on each of the RNAs and these are translated from shorter RNA molecules transcribed from the 3'- end of the genomic RNA (. That from RNA1 is a cell- to- cell movement protein (MP) that enables the virus to move between adjacent plant cells via the plasmodesmata while the function of the product from RNA2 is uncertain but may involve supression of the host plant defence reaction. The genome organisation of a typical member is shown here Genus Fijivirus: in this genus there are 1. RNA. Most of the components encode a single protein and at least 3 of these are structural proteins assembled into the complex virion. For example, recent studies in the genus Carlavirus show that when different species are compared, they have less than 7.
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