Virus resistance induced by NB-LRR proteins involves Argonaute4-dependent translational control.
Active resistance to viruses is afforded by plant disease resistance (R) genes, which encode proteins with nucleotide-binding (NB) and leucine-rich repeat (LRR) domains. Upon recognition of pathogen-derived elicitors, these NB-LRR proteins are thought to initiate a number of signaling pathways that lead to pathogen restriction. However, little is known about the molecular mechanisms that ultimately curtail virus accumulation. Here, we show that the co-expression of a plant NB-LRR protein with its cognate elicitor results in an antiviral response that inhibits the translation of virus-encoded proteins in Nicotiana benthamiana. This antiviral response is dependent on viral cis elements, and, upon activation of the NB-LRR protein, viral transcripts accumulate but do not associate with ribosomes. The induced inhibition of viral transcript translation and NB-LRR-mediated virus resistance were compromised by the downregulation of Argonaute4-like genes. Argonaute proteins have been implicated in small RNA-mediated RNA degradation, and in degradation-independent translational control. Our results suggest that the engagement of Argonaute proteins in the specific translational control of viral transcripts is a key factor in virus resistance mediated by NB-LRR proteins.
Bhattacharjee
Saikat
S
Boyce Thompson Institute for Plant Research, Tower Road, Ithaca, NY 14850, USA.
Zamora
Alejandro
A
Azhar
Muhammad Tehseen
MT
Sacco
Melanie A
MA
Lambert
Lester H
LH
Moffett
Peter
P
D018506:Gene Expression Regulation, Plant; D007113:Immunity, Innate; D000090263:Leucine-Rich Repeat Proteins; D010935:Plant Diseases / Q000821:virology*; D010940:Plant Proteins / Q000378:metabolism*; D014176:Protein Biosynthesis; D011506:Proteins / Q000378:metabolism*; D012367:RNA, Viral / Q000378:metabolism; D014026:Nicotiana / Q000276:immunology / Q000378:metabolism* / Q000821:virology; D014027:Tobacco Mosaic Virus / Q000502:physiology; D014779:Virus Replication
D000090263:Leucine-Rich Repeat Proteins; D010940:Plant Proteins; D011506:Proteins; D012367:RNA, Viral