Occurrence Of Lily Virus Disease And Detection Methods Of Virus

Abstract Lily virus disease is one of the important diseases for infecting lily. It was reported that lily were infected by fourteen kinds of viruses. In this study, main viral pathogens naturally occurred on lily crops, forms of viruses particles and inclusions, symptom types and spatial distribution pattern of lily virus diseased plants were systemically investigated by biological, serology, electron microscope techniques and survey in fields. CMV-Li antiserum was produced and established ELISA systems of detection CMV-Li that it would supply a theoretical basis for lily virus detection in field. All result of the study was summarized as follows: 1. Enzyme –linked immumnosorbent assay (ELISA) detection indicated that Cucumber mosaic virus (CMV) and lily symptomless virus (LSV) were the most important viral pathogens for infecting Gansu lily. The rate of lily mosaic diseases infected by CMV was 40%, by LSV was 80%, mixed by CMV and LSV was 40%.The host range of lily viruses is narrow. It could not infect normal indicator host of CMV, such as Nicotiana tabacum, Nicotiana glutinosa,Chenopodium amaranticolor, but it could infect Cucumber , Datura stramonium , Phaseolus vulgaris(American) and express vein clearing , mosaic and crinkle symptoms . CMV –Li and LSV on lily could be isolated by indicator host Phaseolus vulgaris (American) and cucumber.2. Four kinds of virus particle of spherical, fibrous (long, short) and short rod-shaped were found and inclusion bodies of crystalloid, hexagon, bundle, scroll and pinwheel were observed in the cytoplasm of the mesophyll cells by electron microscope. Accoring to the result of all above,spherical virus and short fibrous virus were identified as Cucumber mosaic virus(29.5nm) and Lily symptomless virus(593.29－639.97×12.15－14.12nm), long fibrous virus and short rod-shaped virus were identified as Potyvirus(757.58－846.25×12.12－12.75nm) and Tobacco rattle virus(500－807.69×153.85－192.31nm).The cell of host were malformed severely by virus infection, the membrane of the cell proliferated and formed myeloid bodies protruding into the vacuole, a large number of virus particles distributed in mesophyll cells, there were some multivesicular bodies in the cytoplasm, the ultrastructure of chloroplast granum was altered, its granum appered sparse and thick , or was forced tightly and became thin, virus particle existed in chloroplast, in some case the chloroplast was destroyed,the starch granule enlarged in chloroplast and the quantity of the mitochondria increased were observed by electron microscope technique. The concentration of chlorophyll in diseased lily leaves of severe mosaic, mild mosaic and mottle mosaic is obviously lower than healthy ones.3. Natural-infected lily crops exhibited diversiform symptoms in Gansu and Qinghai provinces. There were seven types of virus disease symptoms on lily plants ,including mild mosaic (Mm), severe mosaic (Sm), stunting (Stu), rosette stunt (Rstu), yollow stunt (Ys),flat stem buncky leaf (Fsbl), phyllody (Phy).The symptoms of Mm and Sm were the most common symptom in lily plant areas , the rates of Sm and Mm symptom were 43.62% and 39.5%. The rest of symptom was seldom. The more the age of lily bulb as seed, the more virus disease. The disease were more serious in the field growing lily previous than in the field growing wheat,in the low-lying field than higher and dry of ones. The resistance of lily varieties to virus disease was different.4. Aggregation indices and the method of Iwao were used in the study of spatial distribution patterns of the lily virus in the field. The result showed that the diseased plants was aggregation distribution at the beginning of the disease developing, the spatial distribution were uniform distribution at the late stage of the disease, the basic component of distribution was colonies and its distribution was uniform, there was a obvious center of diseased.The theoretical sampling quantity was determined by the rate of diseased plants. Sampling quantity may be between 55...