PubMed · 17027683
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
S E Seal, M J Jeger, F Van den Bosch. 2006. Begomovirus evolution and disease management.. https://doi.org/10.1016/s0065-3527(06)67008-5
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Chili leaf curl virus (ChiLCV) is a Begomovirus chillicapsici that is one of the most devastating viruses impacted on the production of chili in the world, especially in South Asia. In the present study, we combined high-throughput computational genomics with experimental analysis of global diversity. A workflow was created using automated Python scripts to download, curate and process ChiLCV genomes from public database. About 410 complete ChiLCV genomes download from public databases. Using a phylogenetic approach, these isolates were subdivided into 34 strains, belonging to 10 major clades, showing significant genetic diversity. Geographic analysis revealed that Pakistan (207 isolates) and India (148 isolates) were the main sources of ChiLCV diversity and the remainder of the isolates were from Oman, Bangladesh, Iran, Saudi Arabia and Sri Lanka. Recombination was observed as a major evolutionary force as more than twenty recombination events were detected. Analysis of cis-regulatory elements showed a complex structure of the viral promoter, including multiple binding sites for transcription factors, hormone-response elements, light-responsive elements, and stress-responsive elements, indicating a high number of interactions between viral regulatory elements and host signaling pathways. Pangenome analysis showed the presence of a highly dynamic open pangenome made up of strain-specific orthologous groups (species-specific orthogroups). Experimental inoculation of chili plants was also carried out to assess the biological effects of infection, along with phytochemical, FTIR, HPLC, and qPCR analyses.
Tomato chlorotic mottle virus (ToCMoV) is a begomovirus found widespread in tomato fields in Brazil. ToCMoV isolate BA-Se1 (ToCMoV-[BA-Se1]) was shown to trigger the plant RNA silencing surveillance in different host plants and, coinciding with a decrease in viral DNA levels, small interfering RNAs (siRNAs) specific to ToCMoV-[BA-Se1] accumulated in infected plants. Although not homogeneously distributed, the siRNA population in both infected Nicotiana benthamiana and tomato plants represented the entire DNA-A and DNA-B genomes. We determined that in N. benthamiana, the primary targets corresponded to the 5' end of AC1 and the embedded AC4, the intergenic region and 5' end of AV1 and overlapping central part of AC5. Subsequently, transgenic N. benthamiana plants were generated that were preprogrammed to express double-stranded RNA corresponding to this most targeted portion of the virus genome by using an intron-hairpin construct. These plants were shown to indeed produce ToCMoV-specific siRNAs. When challenge inoculated, most transgenic lines showed significant delays in symptom development, and two lines had immune plants. Interestingly, the levels of transgene-produced siRNAs were similar in resistant and susceptible siblings of the same line. This indicates that, in contrast to RNA viruses, the mere presence of transgene siRNAs corresponding to DNA virus sequences does not guarantee virus resistance and that other factors may play a role in determining RNA-mediated resistance to DNA viruses.
Tomato yellow leaf curl disease (TYLCD)-associated viruses present a highly structured population in the western Mediterranean basin, depending on host, geographical region and time. About 1,900 tomato and common bean samples were analyzed from which 111 isolates were characterized genetically based on a genome sequence that comprises coding and non-coding regions. Isolates of three distinct begomoviruses previously described were found (Tomato yellow leaf curl virus, TYLCV, Tomato yellow leaf curl Sardinia virus, TYLCSV, and Tomato yellow leaf curl Málaga virus, TYLCMalV), together with a novel recombinant virus. Mixed infections were detected in single plants, rationalizing the occurrence of recombinants. Except for TYLCV-type strain, single, undifferentiated subpopulations were present for each virus type, probably the result of founder effects. Limited genetic variation was observed in genomic regions, with selection against amino acid change in coding regions.