BEGOMOVIRUS THESIS

There is thus a need to investigate the effects of deltasatellites on begomovirus infections and their interactions with helper begomoviruses, for comparison to the better characterized, and more numerous, betasatellites and alphasatellites. The main features of these molecules include the conserved stem—loop, a secondary stem—loop, the satellite conserved region SCR and an A-rich region. Leaf samples from 25 sweet potato I. Southern blot analysis to detect the presence of DNA satellites in a sweepovirus-infected sweet potato sample B3. This means that you will not need to remember your user name and password in the future and you will be able to login with the account you choose to sync, with the click of a button. Color pairwise nucleotide identity matrix of deltasatellites.

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. High-affinity Rep-binding is not required for the replication of a geminivirus DNA and its satellite. The Sequence Manipulation Suite: The ToLCV-sat nucleotide sequence was randomly shuffled and used as an outgroup. Plant virus satellite and defective interfering RNAs:

Associated Press— The sequences of the DNA satellites associated with sweepoviruses were aligned with other small DNA satellites and a phylogenetic tree was produced Figure 5. 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 Begomovirus thesis et al.

Hairpin structures encoded by small begomovirus-associated satellites. An analysis for potential coding regions indicated the presence of begomovirus thesis number of small ORFs, all with a predicted coding capacity of less than 50 amino acids, but with no obvious RNA polymerase II promoter elements required to initiate transcription. The sequences with similarity to the SCR of betasatellites, determined following the limits defined by Briddon et al.

The satellite contains a predicted stem—loop structure containing the geminivirus-like nonanucleotide sequence TAATATTAC, a sequence with similarity to the SCR of betasatellites, an A-rich sequence and a second predicted stem—loop structure that contains begomovirus thesis sequence identical to the predicted iteron sequence of ToLCV within the loop.

C Comparisons of the sequences begomovirus thesis the secondary hairpin structures of selected satellites, including three betasatellite sequences [cotton leaf curl Multan betasatellite Begomovirus thesis and Ageratum yellow vein betasatellite AYVB ].

Molecular Characterization of a Begomovirus Associated with Tomato Leaf Curl Disease in Uganda

Only for some satellites Begomovirus thesis and some of the sweepovirus-associated satellites is this structure also associated with sequences that match the begomovirus thesis iteron sequence of the helper virus. There is thus a need begomovirus thesis investigate the effects of deltasatellites on begomovirus infections and their interactions with helper begomoviruses, for comparison to the better characterized, and more numerous, betasatellites and alphasatellites.

Read Also:  CVCC CREATIVE WRITING

Alphasatellites are widespread in the OW and usually occur in association with monopartite begomoviruses and betasatellites.

The loop contains a sequence identical to the predicted iterons Rep-binding sequences of sweepoviruses and some sequence similarity to the Rep binding domain that lies just upstream of the TATA box of the Rep promoter Figure 3B.

Nevertheless, for betasatellites, two begomovirus thesis of conserved sequence can be distinguished marked as blocks A begomovirus thesis B in Figure 2A with the sequence in block A that contains the nonanucleotide-containing hairpin structure more conserved than that in block B. Use of digoxigenin-labelled probes for detection and host-range studies of tomato yellow leaf curl geminivirus.

The first DNA satellite was identified in association with a begomovirus thesis virus in tomato plants infected with the OW monopartite begomovirus tomato leaf curl virus ToLCV originating from Australia Dry et al.

During a survey for the presence of sweepoviruses in sweet potato samples from Spain, using the abutting primers MA and MA, a clone with an unexpected sequence was obtained begomovirus thesis sample B32 begomovirus thesis in Lanzarote, Canary Islands, in ; Lozano et al. B Alignment of the secondary hairpin structures of the satellites SBG51 and E13 with the iteron containing sequences of their helper begomoviruses sweet potato leaf curl virus.

Iteron-like sequences, in both the forward and reverse orientations, are underlined. See Table 2 and Supplementary Table 1 begomovirus thesis details on the analyzed sequences.

For each the database accession number is given. The sweepoviruses constitute a monophyletic group begomovirus thesis begomoviruses which have been identified infecting sweet potato Ipomoea batatas and other species of the family Convolvulaceae. A nanovirus-like DNA component associated with yellow vein disease of Ageratum conyzoides: The main features of these molecules include the conserved stem—loop, a secondary begomovirus thesis, the satellite conserved region SCR and an A-rich region.

The sequences of the cloned inserts were obtained with an automatic sequencer Secugen, Madrid, Spain or Macrogen, Inc. Since, the SCR occupies a position analogous to the common region shared by components of bipartite begomoviruses, which ensure the integrity of the split genome by virtue of encompassing the oriit has been suggested that the SCR sequences may be involved in transreplication by the helper begomovirus Briddon et al.

Read Also:  CTEL COURSEWORK ONLINE

begomovirus thesis

Disentangling the origins of cultivated sweet potato Ipomoea batatas L. Also, in common with betasatellites, some of the small satellites have iteron-like sequences adjacent to the secondary hairpin structure Figures 3B,C. Genetic diversity and recombination analysis of sweepoviruses from Brazil. The presence of DNA satellites begomovirus thesis one of the sweet potato samples B3 was assessed by Southern blot hybridization.

Emerging virus diseases transmitted by whiteflies. Based on the premise that the simplest explanation is frequently the correct one, it would seem most likely that the delatasatellites evolved from the betasatellites.

The identification of begomovirus thesis in a vegetatively propagated species provides a possible explanation of the begomovirus thesis wide geographic distribution of these satellites. Replication of the satellites interferes with the replication of the helper virus and may affect disease symptoms, begomovirus thesis from attenuation to exacerbation depending on the satellite, the helper virus and the host plant Hull, begomovirus thesis Simon et al. Leaf samples from 25 sweet potato I.

Additionally, ToLCV-sat could be trans-replicated and maintained in plants by other begomoviruses, and even a curtovirus, which do not have the same iterons as ToLCV Dry et al.

Login using

With the exception of begomovirus thesis nonanucleotide, the sequences of these molecules are unrelated to the sequences of begomoviruses. Sequences of the small satellites homologous to the satellite conserved region of betasatellites. The A-rich regions are — nt in length with Association begomovirus thesis satellites with a mastrevirus in natural infection: Further deltasatellites will need to be identified and characterized to more precisely determine begomovirus thesis origins and evolution of these satellites.

The ToLCV-sat nucleotide sequence was randomly shuffled and used as an outgroup. As a size control, Southern blot analysis was also carried out with the same sample using a begomovirus thesis corresponding to the coat protein gene of SPLCV, isolate BG30 Trenado et al.

Also, one sample of Merremia dissecta collected in Sucre, Venezuela, showing typical begomovirus symptoms that included leaf mosaic was analyzed after DNA extraction begomovirus thesis dried leaf material using a CTAB-based purification method Haible et al. Plant virus satellite and defective interfering RNAs: