What are the physical and chemical properties of plum necrotic ringspot virus disease?

Virus name: Prunus necrotic ringspot virus.

Taxonomic status: Equiaxed unstable ringspot virus belongs to the genus Evans, family Bromiviridae. The code of ICTV is 00.0 10.0.02.0438+05.

Virus synonym: European sour cherry necrotic ringspot virus.

Virus purification: The infected cucumber cotyledons were homogenized with phosphate buffer (0.02mol/L, pH8.0) containing 2- mercaptoethanol and sodium diethyldithiocarbamate, and the supernatant was treated with 0.8 times of calcium phosphate aqueous solution. Suspend the precipitate in phosphate buffer, adjust the pH to 4.8 ~ 5.0 with citric acid, and centrifuge to remove the precipitate. Adjust the supernatant to pH7.0, and centrifuge at ultra-high speed again. The virus can be further purified by sucrose gradient centrifugation and electrophoresis (Fulton, 1970).

Physical and chemical characteristics of virus:

(1) virus particles. Spherical, there are two kinds of particles, the diameter is 22 ~ 23 nm, the molecular weight is 5.2 * 106 ~ 7.3 * 106, sedimentation coefficient 72S(T), 90S(M), 95S(B), A260/A280 =1.

② nucleic acid. The nucleic acid content is 16%, and the four components (RNA 1, 2,3,4) g: a: c: u = 27: 25: 21:27. The whole genome size is 8056nt.

3 protein. The content of protein is 84%, the molecular weight is 25ku, and there are 196 amino acid residues.

Virus strain: There are many strains of Prunus necrotic ringspot virus, which are mainly divided according to the range or symptoms of its herb host plants. Common strains can infect kidney beans and cowpeas systematically, but other strains can't. Danish plum strain and apple mosaic serotype can produce line-line symptoms on plums. Some people also divide different strains into different serotypes according to the serological reaction between them. The pathogenicity of different strains of PNRSV is quite different, and it can be divided into different pathogenic types such as strong virus and weak virus according to the different symptoms caused. Hammond(2003) compared the CP genes of 68 different PNRSV isolates, and found that the sequence characteristics were related to the pathogen type and serotype. PNRSV was divided into three different groups: Ⅰ (PV32), Ⅱ (PV96) and Ⅲ (PE-5). Among them, I (PV32) is mainly composed of virulent strains, and its serotype is CH9；; Ⅱ (PV96) is mainly composed of attenuated strains, and its serotype is CH9；; Ⅲ (PE-5) contains some virulent strains and some non-virulent strains, and the serotypes are mainly CH3 and CH30.

Others: the symptoms of sour cherry shock caused by plum dwarf virus are similar to those of plum necrotic ringspot virus, but generally mild, only found in unexpanded and partially expanded leaves; However, symptoms caused by plum necrotic ringspot virus appear on unexpanded leaflets.