The Merging of Two Dynasties—Identification of an African Cotton Leaf Curl Disease-Associated Begomovirus with Cotton in Pakistan

Cotton leaf curl disease (CLCuD) is a severe disease of cotton that occurs in Africa and Pakistan/northwestern India. The disease is caused by begomoviruses in association with specific betasatellites that differ between Africa and Asia. During survey of symptomatic cotton in Sindh (southern Pakistan) Cotton leaf curl Gezira virus (CLCuGV), the begomovirus associated with CLCuD in Africa, was identified. However, the cognate African betasatellite (Cotton leaf curl Gezira betasatellite) was not found. Instead, two Asian betasatellites, the CLCuD-associated Cotton leaf curl Multan betasatellite (CLCuMB) and Chilli leaf curl betasatellite (ChLCB) were identified. Inoculation of the experimental plant species Nicotiana benthamiana showed that CLCuGV was competent to maintain both CLCuMB and ChLCB. Interestingly, the enations typical of CLCuD were only induced by CLCuGV in the presence of CLCuMB. Also in infections involving both CLCuMB and ChLCB the enations typical of CLCuMB were less evident. This is the first time an African begomovirus has been identified on the Indian sub-continent, highlight the growing threat of begomoviruses and particularly the threat of CLCuD causing viruses to cotton cultivation in the rest of the world

The Spread of Tomato Yellow Leaf Curl Virus from the Middle East to the World

The ongoing global spread of Tomato yellow leaf curl virus (TYLCV; Genus Begomovirus, Family Geminiviridae) represents a serious looming threat to tomato production in all temperate parts of the world. Whereas determining where and when TYLCV movements have occurred could help curtail its spread and prevent future movements of related viruses, determining the consequences of past TYLCV movements could reveal the ecological and economic risks associated with similar viral invasions. Towards this end we applied Bayesian phylogeographic inference and recombination analyses to available TYLCV sequences (including those of 15 new Iranian full TYLCV genomes) and reconstructed a plausible history of TYLCV's diversification and movements throughout the world. In agreement with historical accounts, our results suggest that the first TYLCVs most probably arose somewhere in the Middle East between the 1930s and 1950s (with 95% highest probability density intervals 1905–1972) and that the global spread of TYLCV only began in the 1980s after the evolution of the TYLCV-Mld and -IL strains. Despite the global distribution of TYLCV we found no convincing evidence anywhere other than the Middle East and the Western Mediterranean of epidemiologically relevant TYLCV variants arising through recombination. Although the region around Iran is both the center of present day TYLCV diversity and the site of the most intensive ongoing TYLCV evolution, the evidence indicates that the region is epidemiologically isolated, which suggests that novel TYLCV variants found there are probably not direct global threats. We instead identify the Mediterranean basin as the main launch-pad of global TYLCV movements

Molecular Identification of Weed hosts of Tomato yellow leaf curl virus in southeast of Kerman Province

Introduction Tomato yellow leaf curl virus, TYLCV belongs to the family Geminiviridae and Begomovirus genus (27). In recent years, extensive damage to tomatoes and cucurbits plants in the south and the southeast of Iran has arrived (23). This virus family have circular, and single-stranded DNA genome and are widespread in tropical and subtropical areas (30). They are infected several plant species with economic importance. Begomoviruses are dicot-infecting, whitefly-transmitted viruses with a genome comprised of one or two molecules DNA (5). Up to now, studies have been performed to evaluate the status of distribution, and identification of natural host and assess the genetic diversity, but there is not a comprehensive review about its weed hosts yet. Materials and Methods In this research, The weeds from margins and inside greenhouses and farms of tomato and cucurbit in severely infected areas including Manoojan, Kahnooj, Faryab, Anbrabad and Jiroft to identify weed hosts of the virus in nature, were collected. Identification of collected samples were conducted by botanical specialists. Total DNAs were extracted from leaves according to the method of zhang et al. (1998) and stored at -20 oC. Identification of infected samples were carried out by PCR using degenerate primer pairs PCRv 181/Bc that direct the amplification of˷ 550 bp fragment of mono – and bipartite begomoviruses genome comprising the C-terminal portion of the intergenic region (IR) N-terminal portion of the CPgene. PCR were performed in 25 µl reaction volumes containing 1 µl of template DNA, o.5 µl of Taq DNA polymerase Sinaclon (IRAN), 1.2 µl MgCl2, 0.5 µl dNTPs. 1 µM of each forward and reverse primers, 4.3 µl of 10× reaction buffer and 15.5 distilled water. The amplification were performed using a peqSTAR 96x Termal Cycler (Peqlabe, Germany). PCR conditions consisted of initial denaturing 94 oC for 3 min followed by 30 cycles of denaturation at 94 oC for 50s, annealing at 55 oC for 60s, and extension at 72 oC for 1 min followed by 1 cycle at 72 oC for 10 min. Electrophoresis of polymerase chain reaction products on 1% agarose gel was performed and stained with DNA safe stain (sinaclon-IRAN). The polymerase chain reaction product were sequenced using automatic sequencer AB13730XL (Macrogen, Korea). The resulting sequences were looking similarity and after obtaining a degree of homology, 550 bp fragment of the coat protein gene of four isolates were ordinated by Bio Edit software. Looking for similar sequences were obtained and then achieved the 550 bp fragments of the coat protein gene homology four software isolates Bio edit (21) were ordination. To study the phylogenetic relationship of study strains, the phylogenetic tree was drawn with maximum likelihood way in the MEGA 5 software. Then percentage of similarity at the nucleotide and amino acid sequence with a genetic distance matrix was determined by using the software CLC Main work bench. Results and Discussion: The results showed that four weeds including Chrozophora tinctoria, Heliotropium annum, Malva neglecta and Chenopodium murale were infected with TYLCV. To compare the TYLCV isolates in infected weeds, 550 bp fragment of the coat protein gene in four different strains of the virus was sequenced. Assessment of the genetic similarity between study isolates and strains in the Gene Bank revealed that study isolates with isolates from Gene Bank have similarity in the range of 93/24-99/98% at the nucleotide level and in the range of 87/42-98/15% at the amino acid level. Sixty-six mutations at the nucleotide level in compared sequences in this study was also found. Drawn Phylogenetic tree was confirmed the results of the genetic distance matrix. The results showed that the virus has a wide host range, and identification of weed hosts to remove the maintenance of virus plays an important role in the epidemiology of the disease. and also it’s the management of this disease. This is the first report from Malva neglecta and Chenopodium murale as weed host of TYLCV in Iran. TYLCV causing major damage to the cultivation of tomatoes. Infection caused by it in the South and South East farms in Iran is usually very widespread. Because of the subtropical climate in these areas that is essential for the activity and proliferation of whitefly vector, this virus can cause a high damage in these areas (34). High genetic variability in begomovirus populations infecting different non-cultivated hosts has been reported (28, 35, 38). Conversely, begomovirus populations infecting cultivated hosts seem to have lower variability (6,14,41,43).Wild/non-cultivated plants from different botanical families can sustain a high species diversity of begomoviruses and can play an important epidemiological role serving as alternate/reservoir hosts, preventing local extinctions of the virus when the cultivated host is absent (1, 14). In these cases, whiteflies transmitting begomoviruses between cultivated and non-cultivated hosts contribute to virus evolution and disease epidemics (1, 34). Weeds and plant host of indigenous origin and imported ones can be by a large number of plant viruses including Begomoviruses infectedwhich are as reservoirs host of the virus, the primary focus for infection of crops, and play a pivotal role in the emergence of new viral strains (35). Identification and control of the weeds have an important role in disease management. Relatively high incidence of the virus in the weeds with a high density of whitefly population throughout the year, requires new management guidelines. Conclusion: The results showed that the virus has a wide host range, and identification of weed hosts to remove the maintenance of virus that play an important role in the epidemiology of the disease, in the management of this disease is important. This is the first report from Malva neglecta and Chenopodium murale as weed host of TYLCV in Iran

Transmission properties of Iranian wheat stripe virus

Transmission properties of Iranian wheat stripe virus (IWSV), a tentative member of the genus Tenuivirus, were studied. Results showed that similar to other tenuiviruses, IWSV multiplies in its vector, Unkanodes tanasijevici. In bioassay experiments, IWSV transmission rate by individual U. tanasijevici showed an increase with time after acquisition. IWSV was transovarially transmitted to 88-100% of progeny. The nymphs continued to be infective in the adult stage but with decreased efficiency. Males and females transmitted the virus with equal efficiency. Transmission properties of IWSV confirm the position of the virus in the genus Tenuivirus

Molecular characterization of Iranian wheat stripe virus shows its taxonomic position as a distinct species in the genus Tenuivirus

The full lengths of three genome segments of Iranian wheat stripe virus (IWSV) were amplified by reverse transcription (RT) followed by polymerase chain reaction (PCR) using a primer complementary to tenuivirus conserved terminal sequences. The segments were sequenced and found to comprise 3469, 2337, and 1831 nt, respectively. The gene organization of these segments is similar to that of other known tenuiviruses, each displaying an ambisense coding strategy. IWSV segments, however, are different from those of other viruses with respect to the number of nucleotides and deduced amino acid sequence for each ORF. Depending on the segment, the first 16-22 nt at the 5' end and the first 16 nt at the 3' end are highly conserved among IWSV and rice hoja blanca virus (RHBV), rice stripe virus (RSV) and maize stripe virus ( MStV). In addition, the first 15-18 nt at the 5' end are complementary to the first 16-18 nt at the 3' end. Phylogenetic analyses showed close similarity and a common ancestor for IWSV, RHBV, and Echinochloa hoja blanca virus (EHBV). These findings confirm the position of IWSV as a distinct species in the genus Tenuivirus

First Report of Alfalfa Leaf Curl Virus from Alfalfa in Iran

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