LAUSR

Rice is one of the most important food crops and feeds more than half of the world’s population [1].Arthropod-borne rice viruses have caused devastating epidemics in Asian countries and are amajor threat to food security [2]. However, little is known about the vulnerability of rice crops to viral pathogens [3,4], especially southern rice black-streaked dwarf virus (SRBSDV), rice black-streaked dwarf virus (RBSDV) and rice gall dwarf virus (RGDV), known to induce annual outbreaks by insect transmission in some localities in Asia. To address this question, we first investigated the susceptibility of 136 conventional and hybrid rice varieties widely cultivated or approved for release in China to SRBSDV, which has been circulating in Asian countries since its first report in 2008 [2]. We monitored symptom development and asymptomatic infection in seedlings after inoculation with viruliferous white-backed plant hoppers (Sogatella furcifera, Horváth) in a greenhouse. We found that most of the varieties examinedwere highly susceptible to SRBSDV and developed the characteristic disease symptoms at 45 days postinoculation (Fig. 1A and Supplementary Table S1). The results from greenhouse inoculation with viruliferous insect vectors predict widespread vulnerability of rice cultivars to SRBSDV in rice fields. To test this hypothesis, we planted seedlings of 528 varieties in 3 consecutive years under open field conditions at locations of Nanning and Guilin, Guangxi Province that have recorded a multiyear SRBSDV outbreak from plant hopper transmission. We found that ≥25% of the seedlings from 80%–93% of the examined hybrid or conventional indica