Abstract:

To clarify the pathogens of the tomato leaves exhibiting curling, mottle and mosaic symptoms in Guangxi, four samples suspected of virus infection were collected, and small RNA deep sequencing (sRNA), reverse transcription-polymerase chain reaction (RT-PCR), sequence analysis and phylogenetic trees construction were applied for the viruses detection and genetic and evolutionary analysis. The results showed that 41 contigs from sRNA were annotated as tomato mosaic virus (ToMV) and tomato chlorosis virus (ToCV), respectively. The results of sRNA were also confirmed by RT-PCR, and all the samples were mix-infected by ToMV and ToCV. Nearly complete genome sequences of ToMV and ToCV RNA2 Guangxi isolates were obtained by multiple DNA fragments splicing. The length of the nearly complete genome sequence of ToMV was 6383 bp, named as ToMV-GX. The nearly complete genome sequence of ToCV RNA2 was 8031 bp, named as ToCV-GX. Phylogenetic analysis showed that the ToMV-GX isolate clustered with the ToMV isolates from Shanxi, Inner Mongolia and Hohhot in a big branch, indicating their close evolutionary relationship. ToCV-GX isolates clustered with the ToCV isolates from Taiwan and Guangdong in a big branch, indicating their close evolutionary relationship. The above results showed that ToMV and ToCV were the pathogens that infected tomato showing curling, mottle and mosaic symptoms, and this was the first report of ToMV and ToCV co-infected tomato in Guangxi.

Key words: tomato chlorosis virus, tomato mosaic virus, Guangxi, small RNA deep sequencing, genetic and evolutionary analysis