Record Details
Isolation, purification and other studies of viruses mechanically transmitted from pear
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Isolation, purification and other studies of viruses mechanically transmitted from pear |
| Names |
Nemec, Stanley, Jr.
(creator) Milbrath, J. A. (advisor) |
| Date Issued | 1966-10-27 (iso8601) |
| Note | Graduation date: 1967 |
| Abstract | Knowledge of the viruses which are mechanically transmitted from pear to herbaceous plants and the diseases they cause in pear is not complete. This thesis discusses the means used to mechanically transmit pear viruses, the properties of those viruses and their relationships with latent viruses of apple. Herbaceous plant virus indicators did not develop symptoms when they were grafted with infected pears. Virus was only mechanically transmitted to herbaceous plants when the reducing agent cysteine hydrochloride and a chelator of the copper in polyphenol oxidase, sodium diethyldithiocarbamate, were added to the grinding medium, phosphate buffer. A virus was mechanically transmitted to Chenopodium amaranticolor from four pear species inoculated with one virus source, and Bartlett pear (B-13) previously inoculated with seven virus sources. C. amaranticolor developed local lesions, systemic oakleaf patterns and chlorosis, and was the only genus which became infected. All virus sources were positive for ring mosaic and vein yellows symptoms. The virus which incited ring mosaic symptoms was filtered through inoculated Prunus spp. and in this way was separated from the vein yellows virus. Similar symptoms were incited in C. amaranticolor by a virus mechanically transmitted from pear showing only ring mosaic symptoms. The pear virus isolates incited two local lesion types on C. quinoa. "Type 1" lesion was water-soaked, tan and 2 to 3 mm in diameter. "Type 2" lesion was brown and 1 mm in diameter. The two pear virus isolates were partially purified by homogenizing infected C. quinoa tissue in phosphate buffer, pH 7, containing sodium diethyldithiocarbamate, cysteine hydrochloride and a clarifying agent, bentonite, and concentrating the suspension with one low and one high speed centrifugation. Purified preparations of these isolates infected seven other herbaceous plant genera. The pear virus isolates incited symptoms in Chenopodium identical to the symptoms incited by virus isolates transmitted from apple. Twelve of fifteen apple virus isolates were transmitted from apple sources which had caused a chlorotic leaf spot reaction in Hopa crab apple. The Hopa crab reaction is thought to be caused by the chlorotic leaf spot virus. Physical, chemical and serological properties of the pear viruses show they are closely related to the chlorotic leafspot virus. The two isolate types were not transmitted to B-13 by rubbing partially purified virus on pear leaves, injecting infectious C. quinoa sap into B-13 stems, or by budding and approach grafting infected Chenopodium to B-13. |
| Genre | Thesis/Dissertation |
| Topic | Pear -- Diseases and pests |
| Identifier | http://hdl.handle.net/1957/47012 |
