InterPro domain: IPR022692

Geminiviruses are characterised by a genome of circular single-stranded DNA encapsidated in twinned (geminate) quasi-isometric particles, from which the group derives its name [ 1 ]. Most geminiviruses can be divided into two subgroups on the basis of host range and/or insect vector: i.e. those that infect dicotyledenous plants and are transmitted by the same whitefly species, and those that infect monocotyledenous plants and are transmitted by different leafhopper vectors. The genomes of the whitefly-transmitted African cassava mosaic virus, Tomato golden mosaic virus (TGMV) and Bean golden mosaic virus (BGMV) possess a bipartite genome. By contrast, only a single DNA component has been identified for the leafhopper-transmitted Maize streak virus (MSV) and Wheat dwarf virus (WDV) [ 2 , 3 ]. Beet curly top virus (BCTV), and Tobacco yellow dwarf virus belong to a third possible subgroup. Like MSV and WDV, BCTV is transmitted by a specific leafhopper species, yet like the whitefly-transmitted geminiviruses it has a host range confined to dicotyledenous plants.

Sequence comparison of the whitefly-transmitted Squash leaf curl virus (SqLCV) and Tomato yellow leaf curl virus (TYLCV) with the genomic components of TGMV and BGMV reveals a close evolutionary relationship [ 4 , 5 , 6 ]. Amino acid sequence alignments of Potato yellow mosaic virus (PYMV) proteins with those encoded by other geminiviruses show that PYMV is closely related to geminiviruses isolated from the New World, especially in the putative coat protein gene regions [ 7 ]. Comparison of MSV DNA-encoded proteins with those of other geminiviruses infecting monocotyledonous plants, including Panicum streak virus [ 7 ] and Miscanthus streak virus (MiSV) [ 8 ], reveal high levels of similarity.

This is the central region of the geminivirus rep proteins [ 9 ]. It is found C-terminal to PF00799 and is thought to be responsible for oligomerisation.

1. The nucleotide sequence of an infectious clone of the geminivirus beet curly top virus. EMBO J. 5, 1761-1767
2. The nucleotide sequence of maize streak virus DNA. EMBO J. 3, 3063-8
3. Infectivity and complete nucleotide sequence of the genome of a South African isolate of maize streak virus. Nucleic Acids Res. 16, 229-49
4. Tomato yellow leaf curl virus from Sardinia is a whitefly-transmitted monopartite geminivirus. Nucleic Acids Res. 19, 6763-9
5. Infectivity and complete nucleotide sequence of the cloned genomic components of a bipartite squash leaf curl geminivirus with a broad host range phenotype. Virology 180, 58-69
6. Tomato yellow leaf curl virus: a whitefly-transmitted geminivirus with a single genomic component. Virology 185, 151-61
7. The nucleotide sequence of an infectious insect-transmissible clone of the geminivirus Panicum streak virus. J. Gen. Virol. 73 ( Pt 5), 1041-7
8. The nucleotide sequence and genome structure of the geminivirus miscanthus streak virus. J. Gen. Virol. 72 ( Pt 10), 2325-31
9. The structure of a replication initiator unites diverse aspects of nucleic acid metabolism. Proc. Natl. Acad. Sci. U.S.A. 99, 10310-5