New Disease Reports
New Disease Reports (2005) 10, 45.
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A new begomovirus isolated from Gossypium barbadense in Southern India

R.V. Chowda Reddy 1, V. Muniyappa 2, J. Colvin 1 and S. Seal 1*

*s.e.seal@greenwich.ac.uk

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Accepted: 20 Jan 2005

Leaves were collected from a cotton (Gossypium barbadense) stock plant “MLC” found at the University of Agricultural Sciences, Hebbal, Bangalore, showing mild leaf curl, some vein thickening and enations (Fig. 1).

The infection originated from a naturally-infected G. barbadense at this site and was maintained by successive Bemisia tabaci inoculations. Sequence data generated from cloning PCR products amplified from total MLC-leaf DNA using begomovirus-specific primers (Rojas et al., 1993) enabled the design of primers to amplify the complete DNA-A molecule. The sequence of the cloned complete DNA-A PCR product (2751 nt, AY705380) had 84-85% nucleotide identity with Cotton leaf curl Multan virus (CLCuMV, AJ002447, AJ002459), followed by 83.4% with Malvastrum yellow vein virus (MYVV, AJ457824). A phylogenetic tree was constructed to show the relationship of the MLC virus to other Asian begomoviruses present in GenBank (Fig. 2). Nucleotide identities of individual genes suggest that the DNA-A sequenced is of recombinant origin.

A DNA-B component could not be amplified from MLC-leaf total DNA using degenerate DNA-B specific primers. A DNA-b component was amplified using Briddon et al. (2003) primers and its sequence (AY705381) shared most nucleotide identity (~84%) with DNA-b molecules from cotton and hibiscus in Pakistan (Acc. No. AJ292769 and AJ297908). The conserved C1 gene of the DNA-b molecule showed highest nucleotide identities (89.1-89.6%) and amino acid similarity (80.5-81.4%) with similar sequences from tomato (AJ316035) and cotton G. hirsutum (AJ298903) from Pakistan. Cotton leaf curl diseases in Pakistan and northern India are associated with five distinct begomovirus species which all share a similar DNA-b (Mansoor et al., 2003). Sequence data suggest MLC has not originated from such regions, but is associated with a new begomovirus and distinct DNA-b component. Based on DNA-A sequence taxonomic guidelines (Fauquet et al., 2003), the virus from MLC is a new begomovirus species for which the name Cotton leaf curl Bangalore virus is proposed.

Figure1+
Figure 1: Vein clearing and leaf curling symptoms visible on stock G. barbadense plant showing mild cotton leaf curl symptoms.
Figure 1: Vein clearing and leaf curling symptoms visible on stock G. barbadense plant showing mild cotton leaf curl symptoms.
Figure2+
Figure 2: Neighbour joining tree showing the relationship of Cotton leaf curl Bangalore virus (Acc. No. AY705380; CLCuBV) to selected other full length DNA-A sequences from Asia available from GenBank. Numbers at nodes indicate the bootstrap percentage score out of 1000 replicates. The tree was constructed using ICMV as outgroup and sequence name abbreviations are according to Fauquet et al. (2003), with the exception of sequences ToLCV-Iran (Acc. No. AY297924) and ToLCV-Janti and ToLCBV-Pune, which are unpublished sequences obtained by Chowda Reddy RV.
Figure 2: Neighbour joining tree showing the relationship of Cotton leaf curl Bangalore virus (Acc. No. AY705380; CLCuBV) to selected other full length DNA-A sequences from Asia available from GenBank. Numbers at nodes indicate the bootstrap percentage score out of 1000 replicates. The tree was constructed using ICMV as outgroup and sequence name abbreviations are according to Fauquet et al. (2003), with the exception of sequences ToLCV-Iran (Acc. No. AY297924) and ToLCV-Janti and ToLCBV-Pune, which are unpublished sequences obtained by Chowda Reddy RV.

Acknowledgements

This research was funded by the UK Department for International Development (project R8247, Crop Protection Programme).

References

  1. Briddon RW, Bull SE, Amin I, Idris AM, Mansoor S, Bedford ID, Dhawan P, Rishi N, Siwatch SS, Abdel-Salam AM, Brown JK, Zafar Y, Markham PG, 2003. Diversity of DNA-b, a satellite molecule associated with some monopartite begomoviruses. Virology 312, 106-21.
  2. Fauquet CM, Bisaro DM, Briddon RW, Brown JK, Harrison BD, Rybicki EY, Stenger DC, Stanley J, 2003. Revision of taxonomic criteria for species demarcation in the family Geminiviridae, and an updated list of begomovirus species. Archives of Virology 148, 405-421.
  3. Mansoor S, Briddon RW, Bull SE, Bedford ID, Bashir A, Hussain M, Saeed M, Zafar Y, Malik KA, Fauquet C, Markham PG, 2003. Cotton leaf curl disease is associated with multiple monopartite begomoviruses supported by single DNA-b. Archives of Virology 148, 1969-1986.
  4. Rojas MR, Gilbertson RL, Russell DR, Maxwell DP, 1993. Use of degenerate primers in the polymerase chain reaction to detect whitefly transmitted geminiviruses. Plant Disease 77, 340-347.
This report was formally published in Plant Pathology

©2005 The Authors