New insights into the viruses responsible for sugar beet yellows

Sugar beet leaf yellowing is caused by four viruses, all transmitted by aphids, but belonging to different families which display different biological traits. The modes of transmission vary according to the virus, but all are transmitted by the species Myzus persicae. The Provibe project was intended to acquire knowledge on the biology of the four viruses and their transmission by aphids. Within this project it was confirmed that no additional viruses are involved in the disease. Multi-infections, where plants carry more than one virus, are frequent although their frequency changes from year to year. These combined infections are do not reduce sugar beet yield any more than single infections. However, the coexistence of several viruses within the same plant can have repercussions on their transmissibility by M. persicae. Analysis of viral sequences in both symptomatic and asymptomatic plants did not reveal any candidates that could be used to develop a cross-protection strategy.