Location: Floral and Nursery Plants ResearchTitle: Possible role of the Nt-4/1 protein in macromolecular transport in vascular tissue Author
Submitted to: Plant Signaling and Behavior
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/16/2013
Publication Date: 7/23/2013
Citation: Solovyev, A.G., Makarova, S.S., Remizowa, M.V., Lim, H., Hammond, J., Owens, R.A., Kopertech, L., Schiemann, J., Morozov, S.Y. 2013. Possible role of the Nt-4/1 protein in macromolecular transport in vascular tissue. Plant Signaling and Behavior. 8(10):e25784. Interpretive Summary: Viruses and viroids must interact successfully with the host plant in order to establish infection and to spread throughout the plant; in the case of viruses, these are typically protein:protein interactions, but viroids encode no proteins and rely on RNA:protein or RNA:RNA interactions. A protein known as 4/1, previously shown to interact with a plant virus movement protein, has now been shown to be expressed in the plant vascular system and to influence the speed of invasion of the plant by Potato spindle tuber viroid. This suggests that the 4/1 protein plays a role in signaling in the plant vascular system, aiding mobility of both pathogen-related and cellular RNAs. These results will benefit other scientists examining the interaction pathways involved in cell-to-cell trafficking of macromolecules in plants.
Technical Abstract: The Arabidopsis thaliana 4/1 (At-4/1) protein has a highly alpha-helical structure with potential to interact both with itself and other protein ligands, including the movement proteins of some plant viruses; the Nicotiana tabacum ortholog (Nt-4/1) has similar structure. Here we describe localization of GUS expression in transgenic N. tabacum seedlings under control of the Nt-4/1 promoter, which indicates that transcription is associated with the veins at certain developmental stages, and especially in the hypocotyl. Transient expression in leaves of N. benthamiana of a GFP-4/1 fusion protein was associated with minor veins in the absence of the tombusvirus p19 silencing suppressor, or throughout the leaf in the presence of p19. Viroid accumulation and movement were altered in plants in which 4/1 expression was reduced by virus-induced gene silencing. These localization studies support a role of 4/1 in signaling in the vasculature, including mobility of pathogen-related and cellular RNAs.