Geminiviruses constitute an important group of pathogen characterized by a circular single
stranded DNA genome and a unique geminate particle morphology. The tomato yellow leaf curl
virus (TYLCV), a member of whitefly-transmitted geminiviruses, is a worldwide and
spreading threat for cultured tomatoes. The geminivirus genome consists of one or two
circles of single stranded DNA, each ranging between 2.5 and 3 kb. There are more than 77
geminiviruses described worldwide, these viruses cause devastating plant diseases to many
crops in Egypt. TYLCV is an economically significant whitefly transmitted geminivirus. It
causes about 65% yield losses in tomato. Classical breeding has been attempted to
introduce TYLCV resistance to tomato cultivars, however resistance appears to be
controlled by one to five genes and crosses have produced only tolerant hybrids.
Therefore, production of transgenic tomato plants is more promising to get resistance
against TYLCV. Several strategies have been used to engineer plants resistant to viral
pathogens, based on the concept that the introduction and expression of viral sequences in
plants could interfere with the viral life cycle.
OBJECTIVES
• Study the virus spreading and mode of action.
• Evaluate the damage caused by the virus.
• Study the virus/vector interaction.
• Develop strategies for obtaining transgenic Egyptian tomato
cultivars resistant to tomato yellow leaf curl virus (TYLCV-Eg).
• Establishing and developing transformation and regeneration
systems in tomatoes.
ACHIEVEMENTS
• Constructing genes for plant transformation.
• Establishment and development of a regeneration and
transformation systems for tomato plants (Lycopersicon esculentum).
• Testing resistance of transgenic plants against TYLCV using
antisense RNA construct.
• Purification of TYLCV Virus and production of antibodies.
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