Abstract:

To identify and characterize the candidate viruses infecting Beijing lilac (Syringa lindl) associated with the symptoms of leaf chlorosis, mosaic and leaf curling, small RNA deep sequencing and RT-PCR were conducted with the diseased leaf samples. Ligustrum virus A (LVA) was detected and the complete genome sequences of two isolates were obtained. The Beijing lilac isolate LVA-NXY is 8488 nt in length, while the isolate LVA-HLG is 8478 nt. Sequence similarity analysis showed that LVA-NXY and LVA-HLG were most similar to the LVA-DBLQ isolate from Forsythia suspensa in Shenyang, China. No recombination events were detected among the seven reported LVA isolates. The phylogenetic tree based on the genome sequences indicated that LVA-NXY and LVA-HLG clustered together with LVA-DBLQ and the Syringa vulgaris isolate LVA-DX in the same branch, showing a close phylogenetic relationship. This study reports the complete genome sequence of ligustrum virus A infecting Beijing lilac and explores the molecular characteristics and evolutionary relationships of the virus which provides a theoretical basis for the study of genetic variation and the control of lilac virus disease.

Key words: Syringa lindl, Ligustrum virus A, small RNA, genome, sequence analysis, molecular characteristics, phylogenetic relationship