Molecular Characterization of a Distinct Begomovirus and its Associated Satellite DNA Molecule Infecting Sida acuta in China*

Three viral isolates Hn8, Hn40 and Hn41 were obtained from Sida acuta showing yellow mosaic symptom in the Hainan province, China. Comparison of partial DNA-A sequences amplified with degenerate primers confirmed the existence of single type of Begomovirus. The complete nucleotide sequence of the DNA-A-like molecule of Hn8 was determined to be 2749 nucleotides, having a typical genetic organization of a Begomovirus. Hn8 DNA-A had the highest sequence identity (78%) with that of Ageratum yellow vein China virus-[G13] (AJ558120), and had less sequence identity with other begomoviruses. Based on the above molecular data, Hn8 was thus considered as a new Begomovirus species, for which the name Sida yellow mosaic China virus (SiYMCNV) is proposed. Satellite DNA-b molecules (Hn8-b, Hn40-b and Hn41-b) were found to be associated with Hn8, Hn40 and Hn41 and their complete nucleotide sequences were determined. Sequence analysis showed that Hn8-b, Hn40-b and Hn41-b shared more than 84% nucleotide sequence identity, and they were different from other characterized DNA-b, sharing the highest nucleotide sequence identity (47.8%) with DNA-b of Ageratum yellow vein virus