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The merging of two dynasties--identification of an African cotton leaf curl disease-associated begomovirus with cotton in Pakistan.

Tahir MN, Amin I, Briddon RW, Mansoor S - PLoS ONE (2011)

Bottom Line: 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.Also in infections involving both CLCuMB and ChLCB the enations typical of CLCuMB were less evident.

View Article: PubMed Central - PubMed

Affiliation: Agricultural Biotechnology Division, National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan.

ABSTRACT
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.

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Symptoms induced by virus and betasatellite clones in Nicotiana benthamiana.Shown are pictures of plants (upper panels) and close-up views of the undersides of leaves using transmitted light (lower panels). Shown are a healthy plant (panels A and B) and plants inoculated with CLCuMV and CLCuMB (panels C and D), CLCuGV (panels E and F), CLCuGV and ChLCB (panels G and H), CLCuGV and CLCuMB (panels I and J) and CLCuGV, ChLCB and CLCuMB (panels K and L).
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pone-0020366-g005: Symptoms induced by virus and betasatellite clones in Nicotiana benthamiana.Shown are pictures of plants (upper panels) and close-up views of the undersides of leaves using transmitted light (lower panels). Shown are a healthy plant (panels A and B) and plants inoculated with CLCuMV and CLCuMB (panels C and D), CLCuGV (panels E and F), CLCuGV and ChLCB (panels G and H), CLCuGV and CLCuMB (panels I and J) and CLCuGV, ChLCB and CLCuMB (panels K and L).

Mentions: To assess the biological competence of the CLCuGV in presence of Asian betasatellite, these were introduced into N. benthamiana plants by Agrobacterium-mediated inoculation. As a positive control, CLCuMV with CLCuMB were inoculated. This combination was highly infectious and induced typical symptoms of infection, consisting of leaf curling, vein darkening and enations (Figure 1 panels C and D), phenocopying the symptoms of CLCuD in cotton, within 15 days of inoculation (Table 2). Similarly, all inoculations involving CLCuGV were efficient, all plants becoming infected (Table 2), but in contrast to CLCuMV/CLCuMB, symptoms did not appear until 25 days post-inoculation. This may suggest that CLCuGV is poorly adapted to N. benthamiana, a suggestion that is supported by the fact that all N. benthamiana plants infected with CLCuGV produced copious amounts of defective sub-genomic DNA molecules, in addition to the typical replicative forms of the viral genome (Figure 4). Inoculation of CLCuGV, in the absence of a betasatellite induced relatively mild symptoms consisting of mild stunting, mild leaf curl and vein darkening but no enations (Figure 5, panels E and F). Inoculation of N. benthamiana with CLCuGV with ChLCB induced symptoms that did not differ significantly from those induced by CLCuGV alone (Figure 5, panel G and H). In the presence of CLCuMB, the symptoms of CLCuGV infection were very similar to those induce by CLCuGV alone but additionally included enations (Figure 5, panel I and J). However, in contrast to infections of CLCuMB in the presence of CLCuMV, there was only mild leaf curling. In the presence of both betasatellites, the symptoms induced were again similar to those induced by CLCuGV alone, with only mild leaf curling but there was no evidence of enations. For all plants the presence of the inoculated components, both virus and betasatellites, was confirmed by PCR diagnostics (results not shown). Southern blot analysis of infected plants, probed with a CLCuGV probe, showed that the virus DNA levels were not significantly affected by the presence of the betasatellites (Figure 4). These results show that CLCuGV is able to interact with and maintain two distinct betasatellites in planta.


The merging of two dynasties--identification of an African cotton leaf curl disease-associated begomovirus with cotton in Pakistan.

Tahir MN, Amin I, Briddon RW, Mansoor S - PLoS ONE (2011)

Symptoms induced by virus and betasatellite clones in Nicotiana benthamiana.Shown are pictures of plants (upper panels) and close-up views of the undersides of leaves using transmitted light (lower panels). Shown are a healthy plant (panels A and B) and plants inoculated with CLCuMV and CLCuMB (panels C and D), CLCuGV (panels E and F), CLCuGV and ChLCB (panels G and H), CLCuGV and CLCuMB (panels I and J) and CLCuGV, ChLCB and CLCuMB (panels K and L).
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3102712&req=5

pone-0020366-g005: Symptoms induced by virus and betasatellite clones in Nicotiana benthamiana.Shown are pictures of plants (upper panels) and close-up views of the undersides of leaves using transmitted light (lower panels). Shown are a healthy plant (panels A and B) and plants inoculated with CLCuMV and CLCuMB (panels C and D), CLCuGV (panels E and F), CLCuGV and ChLCB (panels G and H), CLCuGV and CLCuMB (panels I and J) and CLCuGV, ChLCB and CLCuMB (panels K and L).
Mentions: To assess the biological competence of the CLCuGV in presence of Asian betasatellite, these were introduced into N. benthamiana plants by Agrobacterium-mediated inoculation. As a positive control, CLCuMV with CLCuMB were inoculated. This combination was highly infectious and induced typical symptoms of infection, consisting of leaf curling, vein darkening and enations (Figure 1 panels C and D), phenocopying the symptoms of CLCuD in cotton, within 15 days of inoculation (Table 2). Similarly, all inoculations involving CLCuGV were efficient, all plants becoming infected (Table 2), but in contrast to CLCuMV/CLCuMB, symptoms did not appear until 25 days post-inoculation. This may suggest that CLCuGV is poorly adapted to N. benthamiana, a suggestion that is supported by the fact that all N. benthamiana plants infected with CLCuGV produced copious amounts of defective sub-genomic DNA molecules, in addition to the typical replicative forms of the viral genome (Figure 4). Inoculation of CLCuGV, in the absence of a betasatellite induced relatively mild symptoms consisting of mild stunting, mild leaf curl and vein darkening but no enations (Figure 5, panels E and F). Inoculation of N. benthamiana with CLCuGV with ChLCB induced symptoms that did not differ significantly from those induced by CLCuGV alone (Figure 5, panel G and H). In the presence of CLCuMB, the symptoms of CLCuGV infection were very similar to those induce by CLCuGV alone but additionally included enations (Figure 5, panel I and J). However, in contrast to infections of CLCuMB in the presence of CLCuMV, there was only mild leaf curling. In the presence of both betasatellites, the symptoms induced were again similar to those induced by CLCuGV alone, with only mild leaf curling but there was no evidence of enations. For all plants the presence of the inoculated components, both virus and betasatellites, was confirmed by PCR diagnostics (results not shown). Southern blot analysis of infected plants, probed with a CLCuGV probe, showed that the virus DNA levels were not significantly affected by the presence of the betasatellites (Figure 4). These results show that CLCuGV is able to interact with and maintain two distinct betasatellites in planta.

Bottom Line: 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.Also in infections involving both CLCuMB and ChLCB the enations typical of CLCuMB were less evident.

View Article: PubMed Central - PubMed

Affiliation: Agricultural Biotechnology Division, National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan.

ABSTRACT
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.

Show MeSH
Related in: MedlinePlus