Interplay of Rice Stripe Virus and Rice Black Streaked Dwarf Virus during Their Acquisition and Accumulation in Insect Vector.

Marcia Beatriz Moya Fernández,Xifeng Wang,Wenwen Liu,Lu Zhang,Jamal-U-Ddin Hajano

doi:10.3390/v13061121

Abstract

Plant viruses transmitted by hemipteran vectors commonly cause losses to crop production. Rice stripe virus (RSV) and rice black streaked dwarf virus (RBSDV) are transmitted to rice plants by the same vector, the small brown planthopper (SBPH), Laodelphax striatellus Fallén, in a persistent propagative manner. However, rarely do the respective diseases they cause occur simultaneously in a field. Here, we determined the acquisition efficiency of RSV and RBSDV when acquired in succession or simultaneously by SBPH. When RBSDV was acquired first, RSV acquisition efficiency was significantly lower than when only acquiring RSV. However, RBSDV acquisition efficiency from insects that acquired RSV first was not significantly different between the insects only acquiring RBSDV. Immunofluorescence assays showed that the acquisition of RBSDV first might inhibit RSV entry into midgut epithelial cells, but RSV did not affect RBSDV entry. SBPHs were more likely to acquire RBSDV when they were feeding on plants coinfected with the two viruses. When RBSDV was acquired before RSV, RBSDV titer was significantly higher and RSV titer first declined, then increased compared to when only acquiring RBSDV or RSV. Only 5% of the SBPHs acquired both viruses when feeding on plants coinfected with RSV and RBSDV. These results provide a better understanding of the interaction between two persistent viruses when present in the same vector insect and explain why RSV and RBSDV occur in intermittent epidemics.

Highlights

Rice stripe virus (RSV, genus Tenuivirus, family Phenuiviridae) and rice black streaked dwarf virus (RBSDV, genus Fijivirus, family Reoviridae) cause serious yield losses of rice in East Asian countries [1,2,3,4,5,6,7]
We found that coinfection with RBSDV limited RSV acquisition by inhibiting RSV entry into the midgut epithelial cells of small brown planthopper (SBPH) and that only 5% of the insects acquired both RSV and RBSDV from coinfected plants
In the first treatment group (RBSDV-RSV), SBPHs were allowed to feed for 3 days on a plant infected with RBSDV, for 3 days on another plant infected with RSV; the insects were placed on virus-free rice seedlings for 7 days and checked for virus acquisition

Summary

Introduction

Rice stripe virus (RSV, genus Tenuivirus, family Phenuiviridae) and rice black streaked dwarf virus (RBSDV, genus Fijivirus, family Reoviridae) cause serious yield losses of rice in East Asian countries [1,2,3,4,5,6,7]. RSV and RBSDV are transmitted to host plants by the same insect vector, the small brown planthopper The SBPH is an important insect vector of several crop viruses due to its piercing and sucking mouthparts [3,15]. It does not migrate long distances and can complete its life cycle in a variety of Gramineae plants. Some insects can settle in wheat plants infected with RSV or RBSDV in the spring, acquire the viruses to cause virus epidemics in rice or maize [16,17,18]

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Conclusion