Rice stripe virus (RSV) transmitted by the vector, small brown planthopper (SBPH), can cause a severe rice disease. The nucleocapsid (N) protein is the major component of RSV ribonucleoprotein particles (RNPs), and it plays important roles in viral persistent-propagative transmission by SBPH. To gain further insights into the vector components enabling RSV transmission, a GAL4-based yeast two-hybrid system was utilized to find unknown vector factors that interact with the N protein. Thirteen different proteins were identified as factors that interact with the N protein. The interaction between 60S ribosomal protein L18 (RPL18) and the N protein was further studied. Although the expression of RPL18 was not altered in insects during RSV infection, RPL18 was validated to bind directly to RSV RNPs and interact with RSV N protein. Knockdown of RPL18 dramatically reduced viral RNA and protein levels, especially viral protein expression, indicating a requirement for RPL18 in RSV translation and replication. Our results provide evidence that RPL18 is a critical factor required for RSV accumulation in SBPH, which suggests that the vector factor RPL18 may be as a potential target to develop for controlling the transmission of rice virus.
Keywords: Ribosomal protein L18; Rice stripe virus; Small brown planthopper; Viral interaction factors; Virus accumulation.
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