| Geminiviruses are single-stranded circular DNA viruses which are wide distribution of worldwide. The vast majority and wide distribution of geminiviruses belong to the genus Begomovirus. The begomoviruses are also called Whitefly-transmitted geminiviruses (WTGs) which cause great losses in tropic and subtropics area. In southern China, WTGs occurs frequently and the range of distribution is gradually enlarged. Yunnan has unique geographical environment and climate type which make it have rich plant diversity, but also provide conditions for the diversity of WTGs, a high-risk region. The purpose of this study was to identify the genome structure, system evolution, variations of Tomato yellow leaf curl China virus(TYLCCNV) and Papaya leaf curl China virus(PaLCuCNV), two dominant species in Yunnan Province, then analyzed the relationship of WTGs and their beta satellite(DNAp), in order to provide theoretical basis of virus-detection and disease-control.Leaf samples from tomato, pepper, beans and other crops and field weed malvastrurum,ageratum with typical begomoviruses symptoms were collected from different areas in Honghe, Dali, Chuxiong, Dehong, Baoshan, Yuxi of Yunnan province between 2009 and 2010. TYLCCNV and PaLCuCNV were detected at high frequencies. The complete sequences of DNA-A of 13 isolates on TYLCCNV and 7 isolates on PaLCuCNV were obtained, respectively. And obtained 10 isolates of different WTGs with DNAβ, including TYLCCNV/DNAβ, TbCSV/DNAβ, MYVV/DNAβ, MYVYNV/DNAβ. These viral genomes have typical WTGs genome structure features.The complete DNA-A nucleotide sequences of 13 TYLCCNV in Yunnan shared 88.4%～99.9% identities. Phylogenetic analysis indicated that TYLCCNV isolates from different region had significant geographical difference, and the variation was also different at some areas with different climate. In addition the virus did not show obvious host dependence. The variation analysis indicated that the region of mutation and recombination was mainly concentrated in IR, AV1, AC1. Compared the 7 isolates of PaLCuCNV, the mutation of DNA-A was very small. They shared 99.1%～99.8% identities, and had higher identities with Guangxi, Fujian, Henan isolates, sharing 91.3%～99.8% identities. The recombination analysis of PaLCuCNV indicated that it showed close relationship among PaLCuCNV isolates and some WTGs infected ageratum. Compared 10 begomoviruses/DNAβcomplex, the complete DNA-A nucleotide sequences of 10 isolates shared 72.4%-99.3% identities, and DNAp shared 50.5%-98.7% identities. The identity among DNAP was lower than DNA-A.It indicated that the variation of DNAβwas heavier. Phylogenetic analysis showed that DNAβand DNA-A were coevolution for the cluster of DNAβand DNA-A was very similar. In additionβC1 and DNAβalso existed coevolution. Because their phylogenetic tree almost identity. |
