Molecular detection of jujube Mosaic-associated Virus A in Aksu

Abstract:【Objective】Jujube Mosaic-associated Virus A (JuMaVA) was a novel member of the genus Badnavirus in the Caulimoviridae, infesting Chinese jujube tree grown in Aksu, Xinjiang, China. The occurrence regularity of the jujube mosaic-associated virus A in the field was not clear, so it was very difficult to provide proper prevention and control technology guidance for local jujube farmers. Grow-ers usually ignore the prevention and control of the disease in the early stage due to the lack of obvious symptom of mosaic and malformation of jujube leaves. Therefore, it was very important to develop the early diagnosis and monitoring of jujube virus disease and explore the key time point of disease control using the molecular detection technology.【Methods】A pair of highly specific primers (JCD-F)/(JCD-R) were designed using Primer 5.0 software based on the genome sequence of Chinese jujube mosaic-associated virus A which had been cloned from jujube leaves by high throughput sequencing. The speci-ficity of primers were tested by Blast using Blastn in NCBI, and 7 positive samples of plant virus diseas-es were used as primer-specific verification materials, including jujube witches’broom, clove virus, fig virus, apple mosaic virus, tomato yellow leaf curl virus, alfalfa virus and watermelon melon virus col-lected from different fields and orchards in 2019 to 2020 by plant pathology laboratory of Xinjiang Academy of Forestry in different areas in Xinjiang. The total DNA of samples for the specificity and sensitivity verification of primers were extracted according to the instructions of the plant DNA extrac-tion kit, and the molecular detection technology was established by optimizing the reaction system. The samples of jujube leaves with typical mosaic and malformation were collected from Chinese jujube or- chards in different growth periods (from May to September) in 2020. The total DNA of 360 diseased leaves samples of jujube were extracted for specificity detection tests. The molecular detection technolo-gy was applied to detect the infection dynamics of new jujube virus in the fields.【Results】The results showed that the minimum concentration of the total DNA extracted from positive sample of the new ju-jube virus was 4.168 pg·μL-1, using the molecular detection technology, and the jujube mosaic-associat-ed virus A could be detected before the appearance of the mosaic and malformation symptom on the leaves. By using the established molecular detection technology, the infection dynamics of jujube mosa-ic-associated virus A was tracked and detected in the fields, and the infection dynamics of the new ju-jube virus in the field was preliminarily determined, the detection rate of mosaic- associated virus A from jujube leaves was increased as the increase of number of months in growing season .The detection rate was lower in May and June than that in July and August, which were consistent with the results of the field investigation according to the symptom of leaves. It was proved that the key time point to pre-vent the jujube mosaic virus disease was from late May to early June.【Conclusion】The primer pair (JCD-F)/(JCD-R), designed based on the genome sequence of new jujube virus, was highly specific sen-sitive to new jujube virus. The molecular detection technology of jujube new virus could fastly and accurately detect and identify the jujube mosaic virus A, and would be practically valuable