@article{mbs:/content/journal/jgv/10.1099/vir.0.80775-0, author = "Takeda, Atsushi and Nakamura, Wakako and Sasaki, Nobumitsu and Goto, Kaku and Kaido, Masanori and Okuno, Tetsuro and Mise, Kazuyuki", title = "Natural isolates of Brome mosaic virus with the ability to move from cell to cell independently of coat protein", journal= "Journal of General Virology", year = "2005", volume = "86", number = "4", pages = "1201-1211", doi = "https://doi.org/10.1099/vir.0.80775-0", url = "https://www.microbiologyresearch.org/content/journal/jgv/10.1099/vir.0.80775-0", publisher = "Microbiology Society", issn = "1465-2099", type = "Journal Article", abstract = " Brome mosaic virus (BMV) requires encapsidation-competent coat protein (CP) for cell-to-cell movement and the 3a movement protein (MP) is involved in determining the CP requirement for BMV movement. However, these conclusions have been drawn by using BMV strain M1 (BMV-M1) and a related strain. Here, the ability of the MPs of five other natural BMV strains to mediate the movement of BMV-M1 in the absence of CP was tested. The MP of BMV M2 strain (BMV-M2) efficiently mediated the movement of CP-deficient BMV-M1 and the MPs of two other strains functioned similarly to some extent. Furthermore, BMV-M2 itself moved between cells independently of CP, demonstrating that BMV-M1 and -M2 use different movement modes. Reassortment between CP-deficient BMV-M1 and -M2 showed the involvement of RNA3 in determining the CP requirement for cell-to-cell movement and the involvement of RNAs 1 and 2 in movement efficiency and symptom induction in the absence of CP. Spontaneous BMV MP mutants generated in planta that exhibited CP-independent movement were also isolated and analysed. Comparison of the nucleotide differences of the MP genes of BMV-M1, the natural strains and mutants capable of CP-independent movement, together with further mutational analysis of BMV-M1 MP, revealed that single amino acid differences at the C terminus of MP are sufficient to alter the requirement for CP in the movement of BMV-M1. Based on these findings, a possible virus strategy in which a movement mode is selected in plant viruses to optimize viral infectivity in plants is discussed.", }