Soybean antiviral immunity conferred by dsRNase targets the viral replication complex

Abstract

Eukaryotic positive-strand RNA viruses replicate their genomes in membranous compartments formed in a host cell, which sequesters the dsRNA replication intermediate from antiviral immune surveillance. Here, we find that soybean has developed a way to overcome this sequestration. We report the positional cloning of the broad-spectrum soybean mosaic virus resistance gene Rsv4, which encodes an RNase H family protein with dsRNA-degrading activity. An active-site mutant of Rsv4 is incapable of inhibiting virus multiplication and is associated with an active viral RNA polymerase complex in infected cells. These results suggest that Rsv4 enters the viral replication compartment and degrades viral dsRNA. Inspired by this model, we design three plant-gene-derived dsRNases that can inhibit the multiplication of the respective target viruses. These findings suggest a method for developing crops resistant to any target positive-strand RNA virus by fusion of endogenous host genes.

Plant Molecular Responses to Potato Virus Y: A Continuum of Outcomes from Sensitivity and Tolerance to Resistance

“…Another type of R-gene was identified in soybean and confers broad-spectrum resistance to potyviruses. The Rsv4 gene encodes an RNase H protein that is able to interact with viral RNA polymerase complex and, thus, most probably degrades viral RNA when in dsRNA form [49].…”

Extreme Resistance to Viruses in Potato and Soybean

“…Resistance provided by Rsv4 is unique in that it is not conferred via an NLR-type protein, as Rsv4 encodes an RNAse-H family protein with the ability to degrade dsRNA. Interactions between the SMV P3 protein and Rsv4 promote dsRNA degradation and prevent viral replication (Hayes et al, 2000;Maroof et al, 2010;Ishibashi et al, 2019). The ability of Rsv4 to prevent infection declines with age, as mature plants are more susceptible to infection (Hayes et al, 2000;Maroof et al, 2010).…”

Soybean Resistance to Soybean Mosaic Virus

“…A recent study showed that Rsv4 encodes an RNase-H family protein with dsRNA-degrading activity and interacts with the P3 protein of SMV to promote the fusion of dsRNAses with host factors involved in virus replication. This fusion result in the degradation of the viral dsRNAs [65].…”

“…The catalytic subunit of RdRp [65][66][67] CP A 'bridge' between virion particles and aphid stylets in aphid transmission [47], cell-to-cell movement, virus assembly [68,69]…”