Characterizations of the Egyptian isolate of Onion yellow dwarf virus Infecting onion and development of Virus-Free plantlets
Samah A. Mokbel
Department of Virus and Phytoplasma Research, Plant Pathology Research Institute, Agricultural Research Center., Egypt. Dr.SamahMokbel@gmail.com
ABSTRACT
Onion yellow dwarf disease is an economically important disease of onion (Allium cepa L.) caused by Onion yellow dwarf virus (OYDV). In this research we aimed to identify and molecularly characterize the isolate of the OYDV infecting onion plants in Egypt and to obtain OYDV-free plants from infected onions through tissue culture techniques. To achieve our aim, the virus has been isolated from naturally infected onion plants grown in five Egyptian Governorates, Gharbia, Qalyobia, Giza, Fayoum and Beni-Suef then mechanically transmitted onto healthy onion plants in an insect proof greenhouse. The virus identification was done by indirect ELISA using specific antiserum and confirmed by Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) using virus-specific primers. The molecular characterization for the Egyptian isolate has been performed through cloning and sequencing for the OYDV CP gene which amplified by RT-PCR then cloned and sequenced in the TOPO cloning vector. The CP gene sequence has been submitted to the GenBank and compared to other available isolates of OYDV. Sequence alignment and phylogenetic analysis showed that the Egyptian isolate of the OYDV is related to other isolates from Poland and Japan with a similarity ranged from 70 to 93% among those isolates available on GenBank. The virus was eliminated from infected onion plants using cytokinin (kinetin) in a tissue culture line to obtain the OYDV-free plantlets. The effect of different concentration levels of kinetin as well as its efficacy on the OYDV elimination and regeneration of infected onion bulbs were determined.
Key words: Onion, Onion yellow dwarf virus, cloning, RT-PCR, ELISA, Tissue culture, Cytokinin.
How to cite this article:
El-Attar A.K., Mokbel,
A.S. and Hamed, A.H. (2014). Characterizations of the Egyptian
isolate of Onion yellow dwarf virus Infecting Onion and development of
Virus-free plantlets. Egyptian J. of Virology, 11(2): 68-81.
