tailieunhanh - Báo cáo y học: " Characterization of alphasatellites associated with monopartite begomovirus/betasatellite complexes in Yunnan, China"

Characterization of alphasatellites associated with monopartite begomovirus/betasatellite complexes in Yunnan, China | Xie et al. Virology Journal 2010 7 178 http content 7 1 178 VIROLOGY JOURNAL RESEARCH Open Access Characterization of alphasatellites associated with monopartite begomovirus betasatellite complexes in Yunnan China Yan Xie Peijun Wu Pei Liu Huanran Gong Xueping Zhou 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 to while 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. Background Geminiviruses are a group of plant viruses .