Development of a new virus-based vector to control TSWV in tomato plants

Tomato spotted wilt virus (TSWV) is a virus that causes a disease of major concern in tomato plants all over the world being responsible for extremely significant economic losses in this crop which constitutes 72% of the value of fresh vegetables produced worldwide. So far, virus control strategies rely only on preventive sanitary measures or genetic resistance as antiviral products are not available for field use, however its continuous resurgence and spread into new hosts make essential innovative and efficient means of control. 

Virus induced gene silencing (VIGS) allows specific silencing of foreign genes that can be inserted in an optimized virus vector and then inoculated in plants. When a sequence of a viral suppressor gene is introduced in a VIGS vector, the plant infected with this vector will target viral RNA. This will give to the plant a significant advantage in its protection against a possible infection of that virus. The VIGS approach provides the generation of rapid phenotype, no need for plant transformation and can be used for plant protection purposes, at a relatively low cost. Several plant viruses have been used as VIGS vectors however, their large genomes, their difficult manipulation and the reduced number of hosts they infect restrain their use as vectors. 

The Alphanecroviruses Olive mild mosaic virus(OMMV) and Olive latent virus 1 (OLV-1) have characteristics that place them as very promising vector tools. Their small genome makes them easy to manipulate, in addition, they are symptomless or cause only mild systemic symptoms in a wide range of crops, which will ease their manipulation into symptomless constructs, and allow their application to a high number of plants. To our knowledge no studies have been done concerning this matter using these small necroviruses.