Two Conserved Cysteine Residues of the Triple Gene Block Protein 2 Are Critical for Both Cell-to-Cell and Systemic Movement of Bamboo mosaic virus

• Published in: Molecular plant-microbe interactions Vol. 22; no. 11; pp. 1379 - 1388
• Main Authors: Tseng, Yang-Hao, Hsu, Hsiu-Ting, Chou, Yuan-Lin, Hu, Chung-Chi, Lin, Na-Sheng, Hsu, Yau-Heiu, Chang, Ban-Yang
• Format: Journal Article
• Language: English
• Published: St. Paul, MN APS Press 01.11.2009; The American Phytopathological Society
• Subjects: active transport; Amino Acid Sequence; amino acid sequences; Amino Acid Substitution; Bamboo mosaic virus; Biological and medical sciences; endoplasmic reticulum; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Viral - physiology; Molecular Sequence Data; petioles; phloem; Phytopathology. Animal pests. Plant and forest protection; Plant Viral Movement Proteins - chemistry; Plant Viral Movement Proteins - genetics; Plant Viral Movement Proteins - metabolism; Plant Viruses - genetics; Plant Viruses - physiology; Plant viruses and viroids; translocation (plant physiology); transmembrane proteins; triple gene block protein 2; viral proteins; virus movement; Virus; Plant; Plant pathogen; Gene; Microbiology; Flexiviridae; Potexvirus; Bamboo mosaic virus; Protein
• ISSN: 0894-0282; 1943-7706
• DOI: 10.1094/mpmi-22-11-1379

The triple gene block protein 2 (TGBp2) of Bamboo mosaic virus (BaMV) is a transmembrane protein which is known to be required for the cell-to-cell movement of potexviruses. This protein has two conserved Cys residues, Cys-109 and Cys-112, at its C-terminal tail, which is supposed to be exposed on the outer surface of the endoplasmic reticulum (ER) membrane and ER-derived granular vesicles. In this study, we investigated the importance of these two Cys residues on the cell-to-cell and systemic movement of BaMV. Our results indicate that the Cys-to-Ala substitutions in TGBp2 make the cell-to-cell movement of BaMV relatively inefficient and the systemic movement of BaMV severely inhibited. Moreover, the defect in systemic movement is attributed to the inefficient transport of viral RNA in the phloem of petiole. Clearly, TGBp2 is critical not only for the cell-to-cell but also for the systemic movement of BaMV. In addition, the conserved Cys residues are important for the functioning of TGBp2.