Citrus psorosis virus
| Citrus psorosis virus | |
|---|---|
 |
|
| The Citrus psorosis virus | |
| Virus classification | |
| Group: | Group V ((−)ssRNA) |
| Family: | Ophioviridae |
| Genus: | Ophiovirus |
| Species | |
|
Citrus psorosis virus |
|
Citrus psorosis virus
Citrus psorosis virus is a plant pathogenic virus infecting citrus plants worldwide. It is considered the most serious and detrimental virus pathogen of these trees.
The Citrus psorosis virus Egyptian strain (CPsV-EG) was isolated from naturally infected citrus grapefruit (Citrus paradisi Macf.) at ARC. The grapefruit used for CPsV-EG isolatation was found to be free from CTV, CEVd and Spiroplasma citri by testing with DTBIA, tissue print hybridization and Diene's stain respectively (Ghazal et al., 2008).
CPsV-EG isolate was transmitted from infected citrus to citrus by syringe and grafting and herbaceous plants by forefinger inoculation and syringe. The woody indicators and rootstocks were differed in response to CPsV-EG isolate which appeared as no-response, response, sensitivity and hypersensitivity. A partial fragment of RNA3 (coat protein gene) of CPsV-EG (–1140bp and –571bp) was amplified by reverse transcription-polymerase chain reaction (RT-PCR) from grapefruit tissues using two sets primers specific CPsV (CPV3 and CPV4) and (PS66 and PS65) respectively. The virus under study was identified as CPsV-EG isolate according to biological, serological and molecular characters. The serological characters represented as the antigenic determinants of CPsV-EG isolate related to monoclonal antibodies specific CPsV strain where as appeared precipitation reaction by DAS-ELISA and DTBIA (Ghazal et al., 2008).
CPsV-EG was detected on the basis of biological indexing by graft inoculation which gave oak leaf pattern (OLP) on Dweet tangor and serological assay by DAS-ELISA using Mab specific CPsV. CPsV-EG was reacted with variable responses on 16 host plants belonging to 6 families. Only 8 host plants are susceptible and showed visible external symptoms which appeared as local, systemic and local followed by systemic infections (Ghazal et al., 2008).
Young grapefruit leaves of both healthy and CPsV-EG infected plants have been studied histologically and ultrastructurally (Sofy et al., 2007).
In general CPsV-EG-infection affects the upper epidermis of the leaf which is composed of non-tabular parenchyma cells covered by a thin layer of cuticle. Crystal idioblast (CI) containing cells are lacking in the palisade layer and protrude into the epidermis. The oil glands are lacking compared with healthy leaf. Secondary growth occurs in midvein and major lateral veins in smaller veinlets. The vein endings consist of a single trachoid strand of elongated parenchyma cells enclosed by the bundle sheath compared with healthy ones (Sofy et al., 2007).
...
Wikipedia