title: Diversity of DNA beta, a satellite molecule associated with some monopartite begomoviruses.
abstract: DNA beta molecules are symptom-modulating, single-stranded DNA satellites associated with monopartite begomoviruses (family Geminiviridae). Such molecules have thus far been shown to be associated with Ageratum yellow vein virus from Singapore and Cotton leaf curl Multan virus from Pakistan. Here, 26 additional DNA beta molecules, associated with diverse plant species obtained from different geographical locations, were cloned and sequenced. These molecules were shown to be widespread in the Old World, where monopartite begomoviruses are known to occur. Analysis of the sequences revealed a highly conserved organization for DNA beta molecules consisting of a single conserved open reading frame, an adenine-rich region, and a region of high sequence conservation [the satellite conserved region (SCR)]. The SCR contains a potential hairpin structure with the loop sequence TAA/GTATTAC; similar to the origins of replication of geminiviruses and nanoviruses. Two major groups of DNA beta satellites were resolved by phylogenetic analyses. One group originated from hosts within the Malvaceae and the second from a more diverse group of plants within the Solanaceae and Compositae. Within the two clusters, DNA beta molecules showed relatedness based both on host and geographic origin. These findings strongly support coadaptation of DNA beta molecules with their respective helper begomoviruses.
authors.affiliation: Department of Disease and Stress Biology, John Innes Centre, Colney Lane, Norwich, NR4 7UH, UK. rob.briddon@bbsrc.ac.uk
authors.forename: Rob W
authors.initials: RW
authors.lastname: Briddon
authors.forename: Simon E
authors.initials: SE
authors.lastname: Bull
authors.forename: Imran
authors.initials: I
authors.lastname: Amin
authors.forename: Ali M
authors.initials: AM
authors.lastname: Idris
authors.forename: Shahid
authors.initials: S
authors.lastname: Mansoor
authors.forename: Ian D
authors.initials: ID
authors.lastname: Bedford
authors.forename: Poonam
authors.initials: P
authors.lastname: Dhawan
authors.forename: Narayan
authors.initials: N
authors.lastname: Rishi
authors.forename: Surender S
authors.initials: SS
authors.lastname: Siwatch
authors.forename: Aly M
authors.initials: AM
authors.lastname: Abdel-Salam
authors.forename: Judith K
authors.initials: JK
authors.lastname: Brown
authors.forename: Yusuf
authors.initials: Y
authors.lastname: Zafar
authors.forename: Peter G
authors.initials: PG
authors.lastname: Markham
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D017124:Conserved Sequence; D004276:DNA, Satellite / Q000235:genetics*; D019143:Evolution, Molecular; D017791:Geminiviridae / Q000235:genetics* / Q000502:physiology; D014644:Genetic Variation / Q000235:genetics*; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010802:Phylogeny; D010935:Plant Diseases / Q000706:statistics & numerical data / Q000821:virology; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D004276:DNA, Satellite