Characterization of Rice Black-Streaked Dwarf Virus- and Rice Stripe Virus-Derived siRNAs in Singly and Doubly Infected Insect Vector Laodelphax striatellus

PLOS ONE, Dec 2019

Replication of RNA viruses in insect cells triggers an antiviral defense that is mediated by RNA interference (RNAi) which generates viral-derived small interfering RNAs (siRNAs). However, it is not known whether an antiviral RNAi response is also induced in insects by reoviruses, whose double-stranded RNA genome replication is thought to occur within core particles. Deep sequencing of small RNAs showed that when the small brown planthopper (Laodelphax striatellus) was infected by Rice black-streaked dwarf virus (RBSDV) (Reoviridae; Fijivirus), more viral-derived siRNAs accumulated than when the vector insect was infected by Rice stripe virus (RSV), a negative single-stranded RNA virus. RBSDV siRNAs were predominantly 21 and 22 nucleotides long and there were almost equal numbers of positive and negative sense. RBSDV siRNAs were frequently generated from hotspots in the 5′- and 3′-terminal regions of viral genome segments but these hotspots were not associated with any predicted RNA secondary structures. Under laboratory condition, L. striatellus can be infected simultaneously with RBSDV and RSV. Double infection enhanced the accumulation of particular genome segments but not viral coat protein of RBSDV and correlated with an increase in the abundance of siRNAs derived from RBSDV. The results of this study suggest that reovirus replication in its insect vector potentially induces an RNAi-mediated antiviral response.

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Characterization of Rice Black-Streaked Dwarf Virus- and Rice Stripe Virus-Derived siRNAs in Singly and Doubly Infected Insect Vector Laodelphax striatellus

et al. (2013) Characterization of Rice Black-Streaked Dwarf Virus- and Rice Stripe Virus-Derived siRNAs in Singly and Doubly Infected Insect Vector Laodelphax striatellus. PLoS ONE 8(6): e66007. doi:10.1371/journal.pone.0066007 Characterization of Rice Black-Streaked Dwarf Virus - and Rice Stripe Virus -Derived siRNAs in Singly and Doubly Infected Insect Vector Laodelphax striatellus Junmin Li 0 Ida Bagus Andika 0 Jiangfeng Shen 0 Yuanda Lv 0 Yongqiang Ji 0 Liying Sun 0 Jianping Chen 0 Jianming Qiu, University of Kansas Medical Center, United States of America 0 1 State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Ministry of Agriculture Key Laboratory of Biotechnology in Plant Protection, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences , Hangzhou, Zhejiang Province , China , 2 College of Chemistry and Life Science, Zhejiang Normal University , Jinhua, Zhejiang Province , China , 3 Provincial Key Laboratory of Agrobiology, Jiangsu Academy of Agricultural Sciences , Nanjing, Jiangsu Province , China , 4 College of Biotechnology and Life Science, Yangzhou University , Yangzhou, Jiangsu Province , China Replication of RNA viruses in insect cells triggers an antiviral defense that is mediated by RNA interference (RNAi) which generates viral-derived small interfering RNAs (siRNAs). However, it is not known whether an antiviral RNAi response is also induced in insects by reoviruses, whose double-stranded RNA genome replication is thought to occur within core particles. Deep sequencing of small RNAs showed that when the small brown planthopper (Laodelphax striatellus) was infected by Rice black-streaked dwarf virus (RBSDV) (Reoviridae; Fijivirus), more viral-derived siRNAs accumulated than when the vector insect was infected by Rice stripe virus (RSV), a negative single-stranded RNA virus. RBSDV siRNAs were predominantly 21 and 22 nucleotides long and there were almost equal numbers of positive and negative sense. RBSDV siRNAs were frequently generated from hotspots in the 59- and 39-terminal regions of viral genome segments but these hotspots were not associated with any predicted RNA secondary structures. Under laboratory condition, L. striatellus can be infected simultaneously with RBSDV and RSV. Double infection enhanced the accumulation of particular genome segments but not viral coat protein of RBSDV and correlated with an increase in the abundance of siRNAs derived from RBSDV. The results of this study suggest that reovirus replication in its insect vector potentially induces an RNAi-mediated antiviral response. - Funding: This study was funded by grants from the Project of New Varieties Genetically Modified Wheat of China (2008ZX08002-001), China Agriculture Research System (CARS-3-1) from the Ministry of Agriculture of the P.R. China, the Project of Molecular Mechanism of Plant Defense to Pest and Disease (2012CB722504) from the Ministry of Science and Technology of the P.R. China, Modern Agricultural Biotechnology and Crop Disease Control from Key Subject Construction Program of Zhejiang Province, Zhejiang Provincial Natural Science Foundation of China (Q12C140016) and China Postdoctoral Science Foundation (2012M521200). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. . These authors contributed equally to this work. The small brown planthopper (Laodelphax striatellus; family Delphacidae, order Hemiptera) is one of the most economically important insects and is found world-wide, mainly in temperate regions [1]. The agricultural importance of L. striatellus is mainly because it is an efficient vector of two economically important rice viruses: Rice black-streaked dwarf virus (RBSDV) and Rice stripe virus (RSV) in a persistent propagative manner [2,3]. RBSDV and RSV move from the insect gut into the hemolymph or other organs and finally enter the salivary glands [4]. Both viruses can replicate in the different organs of the planthopper and are transmitted to plants during feeding [24]. RBSDV (genus Fijivirus, family Reoviridae) is the causal agent of rice black-streaked dwarf and maize rough dwarf diseases, which cause severe yield losses in Asia. The RBSDV genome contains 10 segments of dsRNA (S12S10) which are numbered in decreasing order of size [5]. RSV is the type member of genus Tenuivirus and its genome consists of 4 single stranded RNA segments. The complementary strand of RSV RNA1 contains a single open reading frame (ORF) while each of the other segments has two non-overlapping ORFs with ambisense coding strategies separated by a non-coding intergenic region [6]. Co-infection of rice by RSV and RBSDV has been observed in the field [7], but it has not been shown whether the two viruses can be present simultaneously within the same insect vector in nature. RNA sil (...truncated)


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Junmin Li, Ida Bagus Andika, Jiangfeng Shen, Yuanda Lv, Yongqiang Ji, Liying Sun, Jianping Chen. Characterization of Rice Black-Streaked Dwarf Virus- and Rice Stripe Virus-Derived siRNAs in Singly and Doubly Infected Insect Vector Laodelphax striatellus, PLOS ONE, 2013, Volume 8, Issue 6, DOI: 10.1371/journal.pone.0066007