No abstract

Potato Leaf Roll Virus (PLRV) is one of the most serious viruses infecting potato plant (Solanum tuberosum L.) in Egypt. Indirect Enzyme Linked Immunosorbent Assay (Indirect-ELISA) results revealed that 70 % of the collected samples were infected with PLRV. A multiplex Polymerase Chain Reaction (PCR) was carried out using three different sets of primers, specific for both PLRV and Potato virus Y (PVY) isolates. For confirmation; the movement coat protein (MP) gene was isolated from the infected plant tissues, and a band with molecular size 336 bp was obtained using Reverse transcription-Polymerase chain reaction (RT-PCR). The DNA sequence of the Egyptian PLRV-Banha-MP gene was deposited in GenBank under an accession number of KR002119. Moreover, sequence analysis revealed that the Egyptian PLRV isolate was closely related to a New Zealand isolate of PLRV (GU002341), with identity of 100%. Transmission electron microscope (TEM) examination of PLRV showed isometric particles, with approximate size of 24-30 nm. The cytopathological examination of the potato plant infected with PLRV revealed many cellular effects such as; partially degraded and deformed chloroplast, starch with an increased size and color change, in addition to nucleus and cytoplasmic bridge. It could be concluded that PLRV is present in Egypt, infecting most of the potato cultivars. Moreover, four different strains of PLRV were detected based on the Single strand conformation polymorphism (SSCP) of the MP gene. The aims of the current study were to identify the PLRV infection of potato plant in Egypt using; molecular, serological and biological methods, in addition to studying the effect of this virus on potato cell organelles. This is the first record of the presence of four different strains of PLRV infecting potato in Egypt, using SSCP assay.

Aims: Cotton production contributes in economic security in Egypt. Cotton leaf curl virus (CLCuV) belongs to the Begomovirus genus and Geminiviridae family that is transmitted by the whitefly Bemisia tabaci. It is the greatest current threat where cotton is grown. In Egypt, a distinct Begomovirus causing leaf curl has been identified in okra, tomato, hollyhock and other malvaceous species suggesting that it could possibly infect Egyptian cotton. The aim of this study was the detection and isolation of this Virus from Egyptian cotton fields. Methodology: Diseased leaves of cotton, okra and tomato plants were collected from different localities during 2009; samples were subjected to DAS-ELISA for viral detection. Coat protein (CP) gene of the virus was amplified by PCR, sequenced and aligned with the others Begomovirus available in the GenBank. Cloning and sub cloning of CP gene for cotton virus were performed and its recombinant protein was separated on SDS-PAGE. DBIA was also used to identify protein of the virus. Results:The amplified fragment of the CP gene was about 280bp in all samples. The CP gene of CLCUV in our study shared 97% identity with CLCuV isolate from Pakistan while, CP gene Original Research Articleamplicon of okra leaf curl virus (OLCUV) showed identity of 84% with three isolates of tomato leaf curl virus (TYLCV) from Chian. The recombinant protein of CLCUV was about 24kDa and positive relatedness was shown between this recombinant protein and TYLCuV antiserum. Conclusion: our study showed the existence of such virus in malvaceous species as okra plant may be causes a serious problem for cotton production in Egypt. Also, the CP gene is a good tool for examination the existence of the virus in the infected fields. The purified protein of CLCUV can use as an antigen to produce its antibodies.