Geminiviridae

The Geminiviridae comprise a group of plant viruses with small, circular, single-stranded deoxyribonucleic acid (DNA)genomes encapsidated in particles that have a twinned quasi-icosahedral (geminate)shape, from which the family derives its name. They are among the smallest of viruses known and are transmitted exclusively by specific insect vectors. Some are associated with highly diverse circular, single-stranded DNA betasatellites that are essential for disease progression. Their association with alphasatellites provides evidence of the interaction of geminiviruses with other families of plant-infecting viruses. Collectively, geminiviruses are pathogens of cereals, vegetable and fibre crops, posing a serious threat to agriculture worldwide. Efforts to control these viruses by conventional means, such as using insecticides against their insect vectors and by breeding resistance, have either proven unsuccessful or have not been durable. For this reason, researchers are increasingly looking to engineered resistance as a means to control these important diseases.