Effects of southern rice black-streaked dwarf virus on the development and fecundity of its vector, Sogatella furcifera

Abstract

BackgroundSouthern rice black-streaked dwarf virus (SRBSDV) threatens rice production in China and Vietnam. The virus is vectored by the migrating white-backed planthopper (WBPH, Sogatella furcifera) in a circulative, propagative, and persistent manner. A persistently-transmitted plant virus might affect its vector’s development and fecundity directly by infecting the vector itself and/or indirectly altering the host plant. This study evaluated the direct and indirect effects of SRBSDV on WBPH performance to better understand the virus–vector–host plant relationship in terms of its effects on the biological parameters of the vector.MethodsThree experimental WBPH populations were established. Viruliferous and non-viruliferous populations were fed on SRBSDV-infected rice seedlings for 48 h as first-instar nymphs; infection status was confirmed by RT–PCR after they died. The control population was fed on healthy rice. Each insect was individually transferred to a healthy rice plant grown in a glass tube at 20°C, 25°C, or 28°C. Life parameters, including nymphal duration, survival rate, adult sex ratio, macropterous proportion, longevity, and oviposition amounts, of each population were measured at each temperature.ResultsThe life parameter data indicated that SRBSDV and infected rice plants adversely influenced WBPH; the effects were temperature dependent. Compared with the control population, viruliferous populations showed significant changes, including prolonged nymphal stages and reduced survival rates at 20°C, while the non-viruliferous population had higher survival rates at 20°C and lower rates at 28°C compared with the control. Both populations had significantly shorter adult life spans at 25°C and lower oviposition amounts at 28°C relative to the control.ConclusionsBoth SRBSDV-infection and feeding on infected rice plants affected vector performance. Although a longer nymphal period benefits viral acquisition and transmission by nymphs and might increase rice infection rate, in general, SRBSDV infection of the vectors and host plants was unfavorable to WBPH population expansion.

Small Interfering RNA Pathway Modulates Initial Viral Infection in Midgut Epithelium of Insect after Ingestion of Virus

“…Previous evidence has shown that persistent propagation of SRBSDV has only a limited adverse effect on its competent WBPH vector and is not pathogenic (49). Here, we found that SRBSDV became highly pathogenic to WBPHs when DCR2 was silenced during viral infection (Fig.…”

Virus altered rice attractiveness to planthoppers is mediated by volatiles and related to virus titre and expression of defence and volatile-biosynthesis genes

“…Some studies have indicated that the lifespans of female BPHs are shortened in SRBSDV-infected rice plants44. The lifespan of WBPHs carrying SRBSDV is less than 15 days at 25 °C45. Additionally, the salivary gland cells of BPHs infected by RRSV undergo programmed cell death46.…”

Rice Reoviruses in Insect Vectors

“…Growing evidence has shown that the persistent propagation of plant viruses adversely affects insect vectors, including prolonging the nymphal stages, shortening adult longevity, reducing survival rate, or decreasing fecundity (22,59,63,77,102,103,123). These adverse changes could be attributed to direct effects of virus-insect interactions or indirect effects of the components from diseased plants.…”

“…It has become clear that viruses can manipulate their vectors either directly or by inducing changes in the host plants (12). The direct adverse effect of infection on insect fitness can hinder expansion of the viruliferous vector population (22,59,77,102). Such adverse effects of viral infection on insect development may also inhibit viral transmission by insect vectors.…”