The Biological Property Of Cucumber Mosaic Virus Satellite RNA-sat405

Cucumber Mosaic Virus Satellite RNA (CMV-satRNA) are small, linear, single-stranded and non-coding RNA that depend on the helper viruses for their replication, encapsidation, and transmission. The sequences of more than 100 CMV–satRNA variants, found associated with over 65 CMV isolates in both subgroups I and II of CMV, have been reported. Most variants found all over the world contain 332–342 nucleotides. Some are considerably larger, with 386–405 nt. The 80nt at 5'end and 45nt at 3'end of CMV satelliteRNA were highly concervative.This paper aims to study the property of sat405 and identify the sypmptoms induced by sat405 with its helper virus CMV-Fny. It was doubted that CMV can contain satellite RNA larger than 400nt. The sequence of sat405 was obtained from NCBI and synthesized into PUC51 vector. The in vitro transcriptional product of sat405 was inoculated onto Nicotiana glutinosa after being mixed with CMV-Fny genomes. CMV-Fny+sat405 was then inoculated onto Nicotiana benthamiana, Nicotiana glutinosa, Solanum lycopersicum hezuo 903 and Nicotiana tabacum. The interaction between satellite RNA,CMV-Fny and host plant was analyzed.The study results showed that the sequence of sat405 remained consisitent after several passages. Both in vitro transcriptional products and leaf sap of CMV-Fny+ sat405 are all infectious. It showed that sat405 accumulation was very high in host plant with CMV-Fny.The existence of sat405 and its interaction with CMV was confirmed. The real time PCR results showed that CMV genome accumulation was upregulated by sat405. The photosynthesis analyzation showed that CMV-Fny decreased the photosynthetic rate of N. benthamiana. CMV-Fny+sat405 and CMV-Fny+satT1 decreased the photosynthetic rate of N. benthamiana compared to CMV-Fny. CMV-Fny+satYN12 increased the photosynthetic rate of N. benthamiana compared to CMV-Fny. It was discovered that sat405 aggravated symptoms induced by CMV-Fny and sat405 increased the accumulation of CMV genomes. The alignment between sat405, satT1 and satYN12 was done by DNASTAR. Comparisons of the sequences reveal that the 5'region and 3'region were homologous. SatT1 lost the middle segment (position 81-107, 114,155—157) compared to sat405 and satYN12. Compared to sat405, satYN12 lost the middle segment position 177-182). Sat405 contained insertion sequences (position 186-213) compared to satT1 and satYN12. Our study showed that the necrogenic region of satRNA can not be determined by alignment of the known satellite RNA only. It should be determined by creating insertion or deletion mutants of satellite RNA and analyze its secondary structure. It showed that sat405 aggravated the symptom of CMV-Fny on host plants.