CROSS-PROTECTION AGAINST VIRUS DISEASES IN FRUIT-TREES

Fruit trees are commonly infected with plant viruses. Several methods have been used to eradicate viruses from plant tissues including chemo therapy, thermotherapy in vitro propagation, and a combination oi some of these protocols. Recent advances in molecular techniques have prov ided a new approach for developing virus resistant genotypes. Genetic engineering of virus resistance into plants has been accomplished usin g several strategies including satellite-RNA-mediated resistance, anti sense RNA-mediated resistance, and coat protein-mediated resistance, a mong others. Current advances in using coat protein-mediated resistanc e have proven promising in protecting several agronomic crops against virus infection. More recently a number of fruit crop species have bee n transformed with coat protein genes of important plant viruses and p romising results have been obtained. This is a general review of cross protection strategies used in combatting virus diseases and the curre nt advances made in genetic engineering of virus resistance in fruit t rees.