title: Genetic analyses of the FRNK motif function of Turnip mosaic virus uncover multiple and potentially interactive pathways of cross-protection.
abstract: Cross-protection triggered by a mild strain of virus acts as a prophylaxis to prevent subsequent infections by related viruses in plants; however, the underling mechanisms are not fully understood. Through mutagenesis, we isolated a mutant strain of Turnip mosaic virus (TuMV), named Tu-GK, that contains an Arg182Lys substitution in helper component-proteinase (HC-Pro(K)) that confers complete cross-protection against infection by a severe strain of TuMV in Nicotiana benthamiana, Arabidopsis thaliana Col-0, and the Arabidopsis dcl2-4/dcl4-1 double mutant defective in DICER-like ribonuclease (DCL)2/DCL4-mediated silencing. Our analyses showed that HC-Pro(K) loses the ability to interfere with microRNA pathways, although it retains a partial capability for RNA silencing suppression triggered by DCL. We further showed that Tu-GK infection triggers strong salicylic acid (SA)-dependent and SA-independent innate immunity responses. Our data suggest that DCL2/4-dependent and -independent RNA silencing pathways are involved, and may crosstalk with basal innate immunity pathways, in host defense and in cross-protection.
authors.forename: Yi-Jung
authors.initials: YJ
authors.lastname: Kung
authors.forename: Pin-Chun
authors.initials: PC
authors.lastname: Lin
authors.forename: Shyi-Dong
authors.initials: SD
authors.lastname: Yeh
authors.forename: Syuan-Fei
authors.initials: SF
authors.lastname: Hong
authors.forename: Nam-Hai
authors.initials: NH
authors.lastname: Chua
authors.forename: Li-Yu
authors.initials: LY
authors.lastname: Liu
authors.forename: Chan-Pin
authors.initials: CP
authors.lastname: Lin
authors.forename: Yu-Hsin
authors.initials: YH
authors.lastname: Huang
authors.forename: Hui-Wen
authors.initials: HW
authors.lastname: Wu
authors.forename: Chin-Chih
authors.initials: CC
authors.lastname: Chen
authors.forename: Shih-Shun
authors.initials: SS
authors.lastname: Lin
mesh_terms: D020816:Amino Acid Motifs; D019943:Amino Acid Substitution; D017360:Arabidopsis / Q000276:immunology / Q000821:virology; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D056738:Cross Protection; D003546:Cysteine Endopeptidases / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D059014:High-Throughput Nucleotide Sequencing; D035683:MicroRNAs / Q000235:genetics; D008954:Models, Biological; D009154:Mutation; D010935:Plant Diseases / Q000276:immunology* / Q000821:virology; D018515:Plant Leaves / Q000276:immunology / Q000821:virology; D030821:Plants, Genetically Modified; D017800:Potyvirus / Q000235:genetics* / Q000502:physiology; D034622:RNA Interference; D043244:Ribonuclease III / Q000235:genetics* / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism; D036226:Seedlings / Q000276:immunology / Q000821:virology; D017423:Sequence Analysis, RNA; D014026:Nicotiana / Q000276:immunology / Q000821:virology; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; D035683:MicroRNAs; D014764:Viral Proteins; C504982:DCL4 protein, Arabidopsis; C511919:DCL2 protein, Arabidopsis; D043244:Ribonuclease III; D003546:Cysteine Endopeptidases; C072775:HC-Pro protein, potyvirus; D020156:Salicylic Acid