Gain-of-function mutant of movement protein allows systemic transport of a defective tobacco mosaic virus

• Published in: iScience Vol. 25; no. 12; p. 105486
• Main Authors: Tran, Phu-Tri, Vo Phan, Mi-Sa, Citovsky, Vitaly
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 22.12.2022; Elsevier
• Subjects: Cell biology; Molecular plant pathology; Virology; Cell biology; Molecular plant pathology; Virology
• ISSN: 2589-0042; 2589-0042
• DOI: 10.1016/j.isci.2022.105486

Functional compensation in response to gene dysfunction is a fascinating phenomenon that allows mutated viruses to regain the capabilities of their wild-type parental strains. In this study, we isolated mutants of tobacco mosaic virus capable of CP-independent systemic movement. These gain-of-function mutants lacked the 16 C-terminal amino acids of the movement protein (MP). Whereas this deletion did not affect the cell-to-cell movement of MP, it dramatically enhanced the viral genomic RNA levels and MP accumulation within the infected cells and altered the subcellular localization of MP from exclusively plasmodesmata (PD) to both PD and plasma membrane. The adapted defective virus suppressed the expression of the ethylene pathway and phloem-associated resistance factors in the inoculated leaves. These findings demonstrate the potential for plant viral MPs to gain a new function that allows viral genomes to move systemically in the absence of the natural viral factor that mediates this spread. [Display omitted] •TMVΔCPmutMP lacking 16 C-terminal residues of MP systemically moves in N. benthamiana•The mutation of MP did not change its cell-to-cell moment but subcellular localization•The mutation of MP enhanced the viral genomic RNA levels and accumulation of MP•TMVΔCPmutMP locally suppressed expression of ET pathway and phloem-associated resistance Virology; Cell biology; Molecular plant pathology