Discovery of aphid-transmitted Rice tiller inhibition virus from native plants through metagenomic sequencing

Abstract

A major threat to rice production is the disease epidemics caused by insect-borne viruses that emerge and re-emerge with undefined origins. It is well known that some human viruses have zoonotic origins from wild animals. However, it remains unknown whether native plants host uncharacterized endemic viruses with spillover potential to rice (Oryza sativa) as emerging pathogens. Here, we discovered rice tiller inhibition virus (RTIV), a novel RNA virus species, from colonies of Asian wild rice (O. rufipogon) in a genetic reserve by metagenomic sequencing. We identified the specific aphid vector that is able to transmit RTIV and found that RTIV would cause low-tillering disease in rice cultivar after transmission. We further demonstrated that an infectious molecular clone of RTIV initiated systemic infection and causes low-tillering disease in an elite rice variety after Agrobacterium-mediated inoculation or stable plant transformation, and RTIV can also be transmitted from transgenic rice plant through its aphid vector to cause disease. Finally, global transcriptome analysis indicated that RTIV may disturb defense and tillering pathway to cause low tillering disease in rice cultivar. Thus, our results show that new rice viral pathogens can emerge from native habitats, and RTIV, a rare aphid-transmitted rice viral pathogen from native wild rice, can threaten the production of rice cultivar after spillover.

Identification and Characterization of Three Novel Solemo-like Viruses in the White-Backed Planthopper, Sogatella furcifera

“…RdRP is a crucial gene involved in virus replication and is considered the most conserved gene among all RNA viruses, making the phylogenetic tree of the RdRPs reliable [ 35 , 36 ]. Moreover, since certain plant viruses within this family are also transmitted by insects [ 18 , 19 , 20 , 37 ], it is highly likely that many other undiscovered members of this family also infect insects [ 36 ].…”

“…Similarly, the rice planthoppers Laodelphax striatellus and Nilaparvata lugens transmit rice reoviruses and also harbor insect-specific reoviruses [ 34 , 46 ]. Within the Solemoviridae family, several viruses significantly infest rice and cause severe disease, such as the rice yellow mottle virus (RSMV) and a novel virus called rice tiller inhibition virus (RTIV) [ 21 , 37 ]. The planthopper WBPH feeds on rice and transmits the important rice viruses SRBSDV.…”