title: NbRABG3f, a member of Rab GTPase, is involved in Bamboo mosaic virus infection in Nicotiana benthamiana.
abstract: The screening of differentially expressed genes in plants after pathogen infection can uncover the potential host factors required for the pathogens. In this study, an up-regulated gene was identified and cloned from Nicotiana benthamiana plants after Bamboo mosaic virus (BaMV) inoculation. The up-regulated gene was identified as a member of the Rab small guanosine triphosphatase (GTPase) family, and was designated as NbRABG3f according to its in silico translated product with high identity to that of RABG3f of tomato. Knocking down the expression of NbRABG3f using a virus-induced gene silencing technique in a protoplast inoculation assay significantly reduced the accumulation of BaMV. A transiently expressed NbRABG3f protein in N. benthamiana plants followed by BaMV inoculation enhanced the accumulation of BaMV to approximately 150%. Mutants that had the catalytic site mutation (NbRABG3f/T22N) or had lost their membrane-targeting capability (NbRABG3f/ΔC3) failed to facilitate the accumulation of BaMV in plants. Because the Rab GTPase is responsible for vesicle trafficking between organelles, a mutant with a fixed guanosine diphosphate form was used to identify the donor compartment. The use of green fluorescent protein (GFP) fusion revealed that GFP-NbRABG3f/T22N clearly co-localized with the Golgi marker. In conclusion, BaMV may use NbRABG3f to form vesicles derived from the Golgi membrane for intracellular trafficking to deliver unidentified factors to its replication site; thus, both GTPase activity and membrane-targeting ability are crucial for BaMV accumulation at the cell level.
authors.affiliation: Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, 402, Taiwan.
authors.forename: Ying-Ping
authors.initials: YP
authors.lastname: Huang
authors.affiliation: Department of Life Sciences, Tzu Chi University, Hualien, 970, Taiwan.
authors.forename: Jia-Hua
authors.initials: JH
authors.lastname: Jhuo
authors.affiliation: Department of Life Sciences, Tzu Chi University, Hualien, 970, Taiwan.
authors.forename: Meng-Shan
authors.initials: MS
authors.lastname: Tsai
authors.affiliation: Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, 402, Taiwan.
authors.forename: Ching-Hsiu
authors.initials: CH
authors.lastname: Tsai
authors.affiliation: Department of Life Sciences, Tzu Chi University, Hualien, 970, Taiwan.
authors.forename: Hong-Chi
authors.initials: HC
authors.lastname: Chen
authors.affiliation: Institute of Plant and Microbial Biology, Academia Sinica, Nankang Taipei, 115, Taiwan.
authors.forename: Na-Sheng
authors.initials: NS
authors.lastname: Lin
authors.affiliation: Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, 402, Taiwan.
authors.forename: Yau-Heiu
authors.initials: YH
authors.lastname: Hsu
authors.affiliation: Department of Life Sciences, Tzu Chi University, Hualien, 970, Taiwan.
authors.forename: Chi-Ping
authors.initials: CP
authors.lastname: Cheng
mesh_terms: D000595:Amino Acid Sequence; D018076:DNA, Complementary / Q000235:genetics; D015536:Down-Regulation / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D055785:Gene Knockdown Techniques; D006056:Golgi Apparatus / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D009029:Mosaic Viruses / Q000502:physiology*; D010935:Plant Diseases / Q000821:virology*; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011523:Protoplasts / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism; D014026:Nicotiana / Q000821:virology*; D015854:Up-Regulation / Q000235:genetics; D020691:rab GTP-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D018076:DNA, Complementary; D010940:Plant Proteins; D049452:Green Fluorescent Proteins; D020691:rab GTP-Binding Proteins
keywords: Bamboo mosaic virus; Golgi membrane; Rab GTPase; vesicle transport