Study of the Initial Steps of Potato Virus X Assembly

Abstract

A b s t r a c tPotato virus X (Potexvirus) is an important pathogen of number of economically significant agricultural plants of the Solanaceae family. Potato virus X (PVX) virions are flexible filamentous particles 515 nm in length and 13.5 nm in diameter with a helical structure. PVX genome consists of a single-stranded RNA (6435 nucleotides) which is capped and polyadenylated. The study of various stages of the infection process of plant viruses during infection, including the assembly of viral particles is of great practical interest. Identification of these mechanisms can be the basis for developing new approaches in virus-free crop production. Herein, the initial stages of potato virus X (PVX) virion assembly were examined on the example of virus-like particles (VLPs) produced by incubation of PVX RNA with PVX coat protein (CP) in vitro. The formation of identical set of VLP with discrete size under different incubation conditions (ionic strength, pH) was shown. However, the amount of VLP of a different size changes depending on incubation conditions. Most efficient VLP similar to the native virion size assembly has been achieved in a buffer of low ionic strength at pH 8.5. PVX RNA fragments from 800 to 5700 nt in length which were protected by coat protein within VLPs were isolated. Their individual analysis confirmed that all of them represent the 5´-terminal fragments of the genomic PVX RNA of different lengths. Thus, it was revealed that RNAs within VLP are genomic RNA 5´-terminal fragments of different lengths. PVX virions assembly initiation at the RNA 5´-end which is cooperatively extending in the 5´-to 3´-end direction was confirmed. Nucleotide sequence analysis of RNA fragments isolated from VLP of different sizes showed that sites capable to form RNA hairpins were discovered near the RNA 3´-end. They could act as «stop-signals» that prevent CP and RNA interaction and continuous cooperative assembling PVX VLP and virions. Probably, CP could «melt» RNA hairpins more or less efficiently and overcome «stop-signals» during the viral particles formation, depending on the conditions of incubation with the RNA in vitro.Êeywords: plant viruses, potato virus X, virus-like particles, RNA, coat protein, virion assembly.

Surface Charge Mapping on Virions and Virus-Like Particles of Helical Plant Viruses

“…7A). The lack of interaction between MNPs and the vRNP head surface may be explained by the competitive binding of all [13]. An analysis of these complexes revealed that most MNPs, upon removal of free RNA, interact with the ends of MN-treated vRNPs (Fig.…”

“…Preparation of TMV and AltMV CP (VLP) repolymers and PVX vRNPs TMV and AltMV CP repolymers were prepared using the techniques described in [11,12], respectively; PVX vRNPs were obtained according to [13].…”

Increased Efficiency of Radiation Inactivation of Virions by Gold Nanoparticles

“…[ 37 ] RNA analysis was carried out using electrophoresis in 1% agarose gel according to. [ 38 ] The gel images were obtained under UV‐illumination using the same gel‐documenting system. The absorption spectra of TMV RNA were measured using NanoDrop 200 (Thermo Scientific, USA) in a wavelength region of λ = 220–350 nm.…”