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PVX
Potato virus X (PVX) is a plant pathogenic virus of the family ''Alphaflexiviridae'' and the order ''Tymovirales''. PVX is found mainly in potatoes and is only transmitted mechanically. There are no insect or fungal vectors for this virus. This virus causes mild or no symptoms in most potato varieties, but when Potato virus Y is present, synergy between these two viruses causes severe symptoms in potatoes. The virion has helical symmetry and a deeply grooved, highly hydrated surface and is made of a single-stranded positive-sense RNA genome of approximately 6.4 kb. This is wrapped in approximately 1300 units of a single coat protein (CP) type, with 8.9 CP units per helix turn. The genome is capped at the 5′-end and poly-adenylated at the 3′-terminus. It contains five open reading frames (ORFs) encoding five proteins: the RNA-dependent RNA Polymerase (RdRP), the movement proteins encoded by three overlapping ORFs that form the Triple Gene Block module (TGBp1, TGBp2, and TGBp3), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viral Diseases Of Potato
Viral diseases of potato are a group of diseases caused by different types of viruses that affect potato crops worldwide and, although they do not affect human or animal health since they are viruses that only infect vegetables, they are a source of great economic losses annually. About 28 viruses have been reported infecting potato crops. However, potato virus X ( PVX), potato virus Y ( PVY), and potato leafroll virus ( PLRV) are the most important viruses worldwide. Some others are of economic importance only in some regions. Such is the case of potato virus M (PVM) in some Asian and European countries. An additional problem is the co-infection of two or more viruses on the same plants. In fact, the joint occurrence of PVX and PVY, or either or both of them with PLRV or Potato virus A ( PVA), produces much more severe symptoms than separate infection of each. The magnitude of economic losses associated with this synergistic effect depends on the types of viruses that are intera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potato Virus Y
Potato virus Y (PVY) is a plant pathogenic virus of the family ''Potyviridae'', and one of the most important plant viruses affecting potato production. PVY infection of potato plants results in a variety of symptoms depending on the viral strain. The mildest of these symptoms is production loss, but the most detrimental is 'potato tuber necrotic ringspot disease' (PTNRD). Necrotic ringspots render potatoes unmarketable and can therefore result in a significant loss of income. PVY is transmissible by aphid vectors but may also remain dormant in seed potatoes. This means that using the same line of potato for production of seed potatoes for several consecutive generations will lead to a progressive increase in viral load and subsequent loss of crop. An increase in potato plant infection with viruses over the past few years has led to considerable losses to the South African potato industry. The increased rate of infection may be attributed to several factors. These include a mar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alphaflexiviridae
''Alphaflexiviridae'' is a family of viruses in the order ''Tymovirales''. Plants and fungi serve as natural hosts. There are 65 species in this family, assigned to six genera. Diseases associated with this family include: mosaic and ringspot symptoms. Taxonomy The following genera are recognized: *'' Allexivirus'' *''Botrexvirus'' *'' Lolavirus'' *'' Platypuvirus'' *''Potexvirus ''Potexvirus'' is a genus of pathogenic viruses in the order '' Tymovirales'', in the family ''Alphaflexiviridae''. Plants serve as natural hosts. There are 48 species in this genus, three of which are assigned to a subgenus. Diseases associated ...'' *'' Sclerodarnavirus'' Structure Viruses in the genus ''Alphaflexiviridae'' are non-enveloped, with flexuous and filamentous geometries. The diameter is around 12-13 nm. Genomes are linear, around 5.4-9kb in length. The genome codes for 1 to 6 proteins. Life cycle Viral replication is cytoplasmic, and is lysogenic. Entry into the host cell is ach ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virus-induced Gene Silencing
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 may ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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