title: Insect symbiotic bacteria harbour viral pathogens for transovarial transmission.
abstract: Many insects, including mosquitoes, planthoppers, aphids and leafhoppers, are the hosts of bacterial symbionts and the vectors for transmitting viral pathogens1-3. In general, symbiotic bacteria can indirectly affect viral transmission by enhancing immunity and resistance to viruses in insects3-5. Whether symbiotic bacteria can directly interact with the virus and mediate its transmission has been unknown. Here, we show that an insect symbiotic bacterium directly harbours a viral pathogen and mediates its transovarial transmission to offspring. We observe rice dwarf virus (a plant reovirus) binding to the envelopes of the bacterium Sulcia, a common obligate symbiont of leafhoppers6-8, allowing the virus to exploit the ancient oocyte entry path of Sulcia in rice leafhopper vectors. Such virus-bacterium binding is mediated by the specific interaction of the viral capsid protein and the Sulcia outer membrane protein. Treatment with antibiotics or antibodies against Sulcia outer membrane protein interferes with this interaction and strongly prevents viral transmission to insect offspring. This newly discovered virus-bacterium interaction represents the first evidence that a viral pathogen can directly exploit a symbiotic bacterium for its transmission. We believe that such a model of virus-bacterium communication is a common phenomenon in nature.
authors.affiliation: State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, People's Republic of China.
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Jia
authors.affiliation: State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, People's Republic of China.
authors.forename: Qianzhuo
authors.initials: Q
authors.lastname: Mao
authors.affiliation: State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, People's Republic of China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, People's Republic of China.
authors.forename: Yuyan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, People's Republic of China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, People's Republic of China.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, People's Republic of China.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, People's Republic of China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
authors.affiliation: State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, People's Republic of China.
authors.forename: Taiyun
authors.initials: T
authors.lastname: Wei
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism; D041963:Bacteroidetes / Q000821:virology*; D036022:Capsid Proteins / Q000378:metabolism; D006430:Hemiptera / Q000382:microbiology*; D056265:Microbial Interactions; D011485:Protein Binding; D012087:Reoviridae / Q000302:isolation & purification*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D036022:Capsid Proteins