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-beta molecules (Hn8-beta, Hn40-beta and Hn41-beta) were found to be associated with Hn8, Hn40 and Hn41 and their complete nucleotide sequences were determined. Sequence analysis showed that Hn8-beta, Hn40-beta and Hn41-beta shared more than 84% nucleotide sequence identity, and they were different from other characterized DNA-beta, sharing the highest nucleotide sequence identity (47.8%) with DNA-beta of Ageratum yellow vein virus.