title: Characterization of alphasatellites associated with monopartite begomovirus/betasatellite complexes in Yunnan, China.
abstract: BACKGROUND
  Alphasatellites are single-stranded molecules that are associated with monopartite begomovirus/betasatellite complexes.
  
  
  RESULTS
  Alphasatellites were identified in begomovirus-infected plant samples in Yunnan, China. All samples that contained alphasatellites also contained betasatellites, but only some samples that contained betasatellites contained alphasatellites. Thirty-three alphasatellites were sequenced, and they ranged from 1360 to 1376 nucleotides. All alphasatellites contain 3 conserved features: a single open reading frame (Rep), a conserved hairpin structure, and an adenine-rich (A-rich) region. On the basis of the phylogenetic tree of the complete nucleotide sequences, the alphasatellites were divided into 3 types with one exception. Type 1 was associated with Tomato yellow leaf curl China virus (TYLCCNV)/Tomato yellow leaf curl China betasatellite (TYLCCNB) complex. Type 2 was associated with Tobacco curly shoot virus (TbCSV)/Tobacco curly shoot betasatellite (TbCSB) complex. Type 3 was associated with TbCSV/Ageratum yellow vein betasatellite (AYVB) complex. Within each type, nucleotide sequence identity ranged from 83.4 to 99.7%, while 63.4-81.3% identity was found between types. Mixed infections of alphasatellites associated with begomovirus/betasatellite complexes were documented.
  
  
  CONCLUSIONS
  Our results validate that alphasatellites are only associated with begomovirus/betasatellite complexes. Thirty-three sequenced alphasatellites isolated from Yunnan Province, China were divided into 3 types--each associated with a specific begomovirus/betasatellite complex. Mix-infections of alphasatellite molecules may not be unusual.
authors.affiliation: State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, P.R. China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Xie
authors.forename: Peijun
authors.initials: P
authors.lastname: Wu
authors.forename: Pei
authors.initials: P
authors.lastname: Liu
authors.forename: Huanran
authors.initials: H
authors.lastname: Gong
authors.forename: Xueping
authors.initials: X
authors.lastname: Zhou
mesh_terms: D031163:Ageratum / Q000821:virology*; D053839:Begomovirus / Q000235:genetics*; D002681:China; D016000:Cluster Analysis; D017124:Conserved Sequence; D004276:DNA, Satellite / Q000737:chemistry / Q000235:genetics*; D005838:Genotype; D018551:Solanum lycopersicum / Q000821:virology*; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010802:Phylogeny; D010935:Plant Diseases / Q000821:virology; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014026:Nicotiana / Q000821:virology*
chemical_list: D004276:DNA, Satellite