Begomovirus thesis

View graph of relations Whitefly-transmissible geminiviruses family Geminiviridae, genus Begomovirus were detected by the polymerase chain reaction PCR in total nucleic acid preparations of tomato and squash leaf samples from different areas in the country.

Begomovirus thesis

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Begomovirus thesis

No use, distribution or reproduction is permitted which does not comply with these terms. This article has been cited by other articles in PMC. Abstract Begomoviruses family Geminiviridae are whitefly-transmitted, plant-infecting single-stranded DNA viruses that cause crop losses throughout the warmer parts of the World.

Sweepoviruses are a phylogenetically distinct group of begomoviruses that infect plants of the family Convolvulaceae, including sweet potato Ipomoea batatas. Two classes of subviral molecules are often associated with begomoviruses, particularly in the Old World; the betasatellites and the alphasatellites.

An analysis of sweet potato and Ipomoea indica samples from Spain and Merremia dissecta samples from Venezuela identified small non-coding subviral molecules in association with several distinct sweepoviruses.

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The sequences of 18 clones were obtained and found to be structurally similar to tomato leaf curl virus-satellite ToLCV-sat, the first DNA satellite identified in association with a begomoviruswith a region with significant sequence identity to the conserved region of betasatellites, an A-rich sequence, a predicted stem—loop structure containing the nonanucleotide TAATATTAC, and a second predicted stem—loop.

These sweepovirus-associated satellites join an increasing number of ToLCV-sat-like non-coding satellites identified recently. Although sharing some features with betasatellites, evidence is provided to suggest that the ToLCV-sat-like satellites are distinct from betasatellites and should be considered a separate class of satellites, for which the collective name deltasatellites is proposed.

Begomovirus, deltasatellites, DNA satellites, Geminiviridae, Ipomoea, Merremia, sweepoviruses, sweet potato Introduction Conventional satellites are subviral agents which lack genes that encode functions needed for replication, depending instead for their multiplication on the co-infection of a host cell with a helper virus Briddon et al.

Two major classes of satellites may be distinguished, satellite viruses that encode a structural protein that encapsidates their genome, and satellite nucleic acids that encode either non-structural proteins, or are non-coding, and are encapsidated by the coat protein CP of helper viruses.

The genetic material of satellites is distinct from that of the genome of their helper viruses. Replication of the satellites interferes with the replication of the helper virus and may affect disease symptoms, ranging from attenuation to exacerbation depending on the satellite, the helper virus and the host plant Hull, ; Simon et al.

They are transmitted exclusively by the whitefly Bemisia tabaci Hemiptera: Aleyrodidae and cause important diseases of dicotyledonous crops worldwide Navas-Castillo et al. The sweepoviruses constitute a monophyletic group of begomoviruses which have been identified infecting sweet potato Ipomoea batatas and other species of the family Convolvulaceae.

Typical of monopartite begomoviruses originating from the Old World OWthe genomes of sweepoviruses encode two genes the CP and V2 in the virion-sense and four [the replication associated protein Repthe transcriptional activator protein TrAPthe replication-enhancer protein REn and the C4 protein] in the complementary-sense.

Begomoviruses Thesis Paper - - Hoegger Farmyard

Virion- and complementary-sense genes diverge from an intergenic region IR that contains a predicted stem—loop structure with the conserved between most geminiviruses nonanucleotide sequence TAATATTAC forming part of the loop. The IR also contains repeated short sequence motifs known as iterons surrounding the TATA box of the Rep promoter that are Rep binding sites and, together with the stem—loop structure, form the origin of virion-sense DNA replication ori.

The sweepoviruses cluster as a branch in the begomovirus phylogenetic tree below the divergence between the OW and New World NW branches, corresponding to the major clades in the genus Lozano et al.Chapter 3 of this thesis uses the geminivirus model system to identify the DRB protein that functions with AGO4 and DCL3 in the RdDM pathway.

It is shown that like dcl3 deficient plants, drb3 mutant plants are hypersusceptible to geminiviruses. Studies carried out in the thesis entitled, ‘Genome organization and mechanism of RNA silencing suppression of begomoviruses infecting some .

and Begomovirus) according to their genome organizations and biological properties (Fauquet et al., , ).

Begomovirus thesis

Mastreviruses typified by maize streak virus (MSV) are transmitted by leafhoppers in the genus Cicadulina and together with the begomoviruses, which are. CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): Diseases caused by begomoviruses (family Geminiviridae, genus Begomovirus) constitute a serious constraint to vegetable production in Nicaragua as they are associated with large economical losses.

This thesis was done in an effort to identify and characterize the begomoviruses responsible for the tomato diseases and. PhD Thesis Wageningen references and summaries in English and Dutch.

ISBNX Begomovirus DNA-A codes for proteins responsible for particle encapsidation (AV1), viral replication (AC1 and AC3), regulation of gene expression and for some. Begomovirus susceptibility in wild Nicaraguan tomato populations University of Agricultural Sciences, EX Independent project/degree project in Biology C, 15 HEC Bachelor’s thesis, Karin Rasmusson ISSN Nr Begomovirusmottaglighet i vilda nicaraguanska tomatpopulationer Begomovirus susceptibility in wild.

Natural occurrence of a begomovirus on Pigeonpea in India