title: Incomplete DRB4-dependence of the DCL4-mediated antiviral defense.
abstract: The double-stranded RNA-binding protein DRB4 of Arabidopsis was shown previously to contribute to the DICER-LIKE 4 (DCL4)-mediated biogenesis of viral small interfering RNAs (vsiRNAs) of 21 nucleotides (nt) in size. However, it is unclear whether all 21-nt vsiRNAs are dependent on this DRB4-DCL4 partnership. To resolve this question, we generated dcl2drb4 and dcl4drb4 double knockout mutants, and subjected them to infections with CPB-CC-PDS, a turnip crinkle virus mutant capable of inducing silencing of the PHYTOENE DESATURASE gene. The dcl2drb4 double knockouts caused a far smaller loss of antiviral silencing than dcl2dcl4. In addition, although both drb4 and dcl4 single mutants permitted a consistent (but small) increase in viral RNA levels, the drb4 mutant correlated with a less pronounced reduction of 21-nt vsiRNAs. Therefore, a substantial subset of DCL4 antiviral activity is DRB4-independent, and may involve other DRB proteins that compensate for loss of DRB4.
authors.affiliation: Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences/ Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, P.R. China.|Department of Plant Pathology, The Ohio State University, Wooster, Ohio, USA.|Fujian Province Key Laboratory of Plant Virology/ Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, P.R. China.|State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, China.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences/ Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, P.R. China.|Department of Plant Pathology, The Ohio State University, Wooster, Ohio, USA.
authors.forename: Xiuchun
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences/ Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, P.R. China.
authors.forename: Kunxin
authors.initials: K
authors.lastname: Wu
authors.affiliation: Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences/ Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, P.R. China.
authors.forename: Zhixin
authors.initials: Z
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, China.
authors.forename: Dawei
authors.initials: D
authors.lastname: Li
authors.affiliation: Department of Plant Pathology, The Ohio State University, Wooster, Ohio, USA.
authors.forename: Feng
authors.initials: F
authors.lastname: Qu
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000037:antagonists & inhibitors / Q000235:genetics; D019184:Carmovirus / Q000235:genetics; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000235:genetics; D010088:Oxidoreductases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D012367:RNA, Viral / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism*; D043244:Ribonuclease III / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000235:genetics*
chemical_list: D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; C511456:DRB4 protein, Arabidopsis; D034741:RNA, Small Interfering; D012367:RNA, Viral; D016601:RNA-Binding Proteins; D010088:Oxidoreductases; C022398:phytoene dehydrogenase; C504982:DCL4 protein, Arabidopsis; C511919:DCL2 protein, Arabidopsis; D043244:Ribonuclease III