Discovery and molecular identification of a novel bunyavirus in the Asian Citrus Psyllid (Diaphorina citri)

Jing Chen ¹ Luqin Liu ¹ Song Zhang ¹ Zhipeng Xie ¹ Jiamei Liang ¹ Fulin Yan ¹ Yaqin Song ² Xuefeng Wang ¹ Changyong Zhou ¹ Mengji Cao ¹ Jinxiang Liu ^1*

• ¹ Southwest University, Chongqing, China
• ² Guangxi Citrus Breeding and Cultivation Research Center of Engineering Technology/Guangxi Academy of Specialty Crops, Guilin, Guangx, China

The Asian citrus psyllid (ACP, Diaphorina citri) is an important vector of "Candidatus Liberibacter asiaticus" (CLas), the causal pathogen of Huanglongbing (HLB). Here, high-throughput sequencing of RNA transcriptomic libraries from ACPs was conducted to identify viruses associated with ACPs and HLB. A novel negative-sense RNA virus, tentatively referred to as Diaphorina citri bunyavirus 2 (DcBV2) was identified and subsequently characterized. Genome analyses revealed that the total genome size of DcBV2 is 11,690 nucleotides (nt) in length, with large, medium, and small segments of 6,498, 3,341 nt, and 1,851 nt, respectively. The RNA dependent RNA polymerase (RdRp) encoded by the large segment shared high sequence identity and phylogenetic affiliation with RdRp from DcBV, which is another member of the family Phasmaviridae within the class Bunyaviricetes. Although DcBV2 is most closely related to DcBV, the ORF region of their L fragment only share 54.34% nt similarity, suggesting that DcBV2 is a novel species. Experimental analysis indicated that DcBV2 is vertically transmitted and exhibited highest infection rates in the salivary glands of ACPs. The discovery of this virus broadens the known candidate agents that could be used in biocontrol of Diaphorina citri or HLB.