Pathogen Identification And Genome Cloning Of Common Medicinal Plant Virus Diseases

China is one of the countries with the largest number and the longest cultivation history of medicinal plants.Recently,the occurrence of viral disease of medicinal plants has been increasing.Viral disease has become one of the main factors limiting the growth of medicinal plants.However,the research on viral diseases of medicinal plants is still very scarce.The purpose of this study is to investigate the occurrence of virus diseases of common medicinal plants and identify the pathogens,so as to lay a foundation for the prevention and treatment of viral diseases of medicinal plants and further research.RT-PCR was used in combination with biological detection and sequencing.The occurrence and infection of virus in Panax ginseng,Chrysanthemum morifolium,Panax quinquefolius,Siraitia grosvenorii,Pseudostellaria heterophylla,Lycium barbarum,Atractylodes macrocephala,Mentha haplocalyx,Datura stramonium and Arctium lappa were studied.Virus infection was detected on Siraitia grosvenorii,Chrysanthemum morifolium,Pseudostellaria heterophylla,Mentha haplocalyx and Datura stramonium,In addition,a RT-PCR detection system for viral diseases of medicinal plants was established,which provided technical support for the subsequent large-scale investigation of viral diseases of medicinal plants.HTS found viruses that were more similar to Carlavirus in chrysanthemum samples which showing dwarfing symptoms.The complete sequence of the virus was determined by RT-PCR and RACE.The virus named CVR is a new virus of genus Carlavirus.The genomic RNA of CVR consists of 8,874 nucleotides(nt),excluding the poly(A)tail,contains six putative ORFs,and has a genomic organization typical of members of the genus Carlavirus.Woad(Isatis tinctoria L.)plants with mosaic symptoms have been found in Beijing.It was detected by RT-PCR to be infected by CMV.Phylogenetic analysis based on nucleotide sequences of CP genes showed that CMV-It belonged to subgroup I.To our knowledge,this is first identification of CMV in woad by RT-PCR.This work provided data for research and control of woad mosaic disease.Samples of Digitalis lanata plants were collected in autumn 2016 and spring 2017 respectively.By biological detection and RT-PCR detection,the autumn samples were infected by CMV and BWYV,the spring samples were infected by BBWV2 and YoMV.Specific primers were designed for RT-PCR to clone the sequence of the viruses.To our knowledge,this is the first report of CMV and BWYV,BBWV2 and YoMV in Digitalis lanata.