Pathogenic RNA Plant Virus Jumps to Honeybees

A viral pathogen that typically infects plants has been found in honeybees and could help explain their decline. Researchers working in the United States and Beijing, China reported their findings on January 21, 2014 in mBio, the online open-access journal of the American Society for Microbiology. The routine screening of bees for frequent and rare viruses "resulted in the serendipitous detection of Tobacco Ringspot Virus (image), or TRSV, and prompted an investigation into whether this plant-infecting virus could also cause systemic infection in the bees," says Dr. Yan Ping Chen from the U.S. Department of Agriculture's Agricultural Research Service (ARS) laboratory in Beltsville, Maryland, an author on the study. "The results of our study provide the first evidence that honeybees exposed to virus-contaminated pollen can also be infected and that the infection becomes widespread in their bodies," says lead author Dr. Ji Lian Li, from the Chinese Academy of Agricultural Science in Beijing. "We already know that honeybees, Apis melllifera, can transmit TRSV when they move from flower to flower, likely spreading the virus from one plant to another," Dr. Chen adds. Notably, about 5% of known plant viruses are pollen-transmitted and thus potential sources of host-jumping viruses. RNA viruses tend to be particularly dangerous because they lack the 3'-5' proofreading function which edits out errors in replicated genomes. As a result, viruses such as TRSV generate a flood of variant copies with differing infective properties. One consequence of such high replication rates are populations of RNA viruses thought to exist as "quasispecies," clouds of genetically related variants that appear to work together to determine the pathology of their hosts.