Supplementary material from "Rice black-streaked dwarf virus P10 suppresses protein kinase C in insect vector through changing the subcellular localization of LsRACK1"

Rice black-streaked dwarf virus (RBSDV) was known to be transmitted by small brown planthopper (SBPH) in a persistent, circulative and propagative manner in nature. Here, we show that RBSDV major outer capsid protein (also known as P10) suppresses the protein kinase C (PKC) activity of SBPH through interacting with receptor for activated protein kinase C 1 (LsRACK1). The N terminal of P10 (amino acids (aa) 1–270) and C terminal of LsRACK1 (aa 268–315) were mapped to be crucial for the interaction. Confocal microscopy and subcellular fractionation showed that RBSDV P10 fused to eGFP formed vesicular structures associated with endoplasmic reticulum (ER) membranes in Spodoptera frugiperda nine cells. Our results also indicated that RBSDV P10 retargeted the initial subcellular localization of LsRACK1 from cytoplasm and cell membrane to ER and affected the function of LsRACKs to activate PKC. Inhibition of RACK1 by dsRNA-induced gene silencing significantly promoted the replication of RBSDV in SBPH. In addition, PKC pathway participates in the antivirus innate immune response of SBPH. This study highlights that RACK1 negatively regulates the accumulation of RBSDV in SBPH through activating the PKC signalling pathway, and RBSDV P10 changes the subcellular localization of LsRACK1 and affects its function to activate PKC.This article is part of the theme issue ‘Biotic signalling sheds light on smart pest management’.