Hindawi Advances in Virology Volume 2018, Article ID 1973705, 11 pages https://doi.org/10.1155/2018/1973705 Review Article Alternanthera mosaic potexvirus: Several Features, Properties, and Application Ekaterina Donchenko, Ekaterina Trifonova , Nikolai Nikitin , Joseph Atabekov , and Olga Karpova Department of Virology, Lomonosov Moscow State University, Moscow 119234, Russia Correspondence should be addressed to Nikolai Nikitin; [email protected] Received 21 March 2018; Accepted 23 May 2018; Published 19 June 2018 Academic Editor: Finn S. Pedersen Copyright © 2018 Ekaterina Donchenko et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Alternanthera mosaic virus (AltMV) is a typical member of the Potexvirus genus in its morphology and genome structure; still it exhibits a number of unique features. Tey allow this virus to be considered a promising object for biotechnology. Virions and virus-like particles (VLPs) of AltMV are stable in a wide range of conditions, including sera of laboratory animals. AltMV VLPs can assemble at various pH and ionic strengths. Furthermore, AltMV virions and VLPs demonstrate high immunogenicity, enhancing the immune response to the target antigen thus ofering the possibility of being used as potential adjuvants. Recently, for the frst time for plant viruses, we showed the structural diference between morphologically similar viral and virus-like particles on AltMV virions and VLPs. In this review, we discuss the features of AltMV virions, AltMV VLP assembly, and their structure and properties, as well as the characteristics of AltMV isolates, host plants, infection symptoms, AltMV isolation and purifcation, genome structure, viral proteins, and AltMV-based vectors. 1. Introduction advantages for successful application in biotechnology [4, 7– 9]. Alternanthera mosaic virus (AltMV) was frst described in 1999 as “isolate 451/1” in the state of Queensland, Australia [1]. Te new virus was isolated from Alternanthera pungens 2. AltMV Isolates and Their Distribution plants of the family Amaranthaceae.AltMVbelongstothe Soon afer AltMV had been discovered in Australia, other iso- genus Potexvirus and the family Alphafexiviridae.TeAltMV lates were derived from plants in Europe [10, 11], USA [2, 12– genome is a positive-sense single-stranded RNA 6604-6607 16], Brazil [17], and Asia [18]. Nowadays AltMV is reported to nt long depending on the isolates. AltMV virions represent be spread all over the world, and capable of infecting plants fexible flamentous particles with helical symmetry made up of various families including ornamental plants and crops of one type of coat protein (CP) subunits. Te mean length [1, 19]. To date, complete nucleotide sequences are deter- of AltMV virions equals 554 nm [1], 536 nm [2], or 570 nm minedforthefollowingAltMVisolates:AltMV-0c (6604 nt [3]. As reported by Mukhamedzhanova et al.[3],thevirions long), AltMV-MU (6606 nt), and AltMV-PA (6607 nt). Four are 13 nm in diameter. Recently AltMV virion diameter was biologically active cDNA of “infectious clones” (3-1, 3-7, 4- corrected to 13.5 nm by means of cryoelectron microscopy 1, and 4-7) were derived from AltMV-SP genome; the com- [4]. plete nucleotide sequences of these clones were established Since plant viruses and virus-like particles (VLPs) are (6607nt).Tenucleotidesequencesoftheotherisolates essentially safe for humans they seem promising for techno- have been only partially determined [2, 14, 20]. logical advances in a broad range of areas from microelec- Te diversity of the obtained isolates both in terms of tronics to developing candidate vaccines and adjuvants [5, 6]. thehostplantsbeingthetargetsforvirulenceandgeograph- AltMV virions and VLPs have a considerable number of ical distribution implies the existence of phylogenetically 2 Advances in Virology Table 1: AltMV isolates. Origin of Virus isolate Accession no. Authors Original host infected plants Phlox-like isolates Geering and Tomas, Alternanthera AltMV-AU AF080448 Australia, QLD 1999 pungens Hammond et al., AltMV-`0 AY863024 Phlox stolonifera USA, PA 2004,2006a,b Hammond et al., Phlox stolonifera cv. AltMV-SP AY850931 USA, MD 2004,2006a,b Sherwood Purple Hammond et al., Phlox stolonifera cv. AltMV-BR AY850928 USA, MD 2004,2006a,b Blue Ridge AltMV-NAN GU126686 Tang et al.,2010 Nandina domestica USA, OK Hammond and Phlox stolonifera cv. AltMV-BW JX457329 USA, MD Reinsel, 2015 Bruce's White Hammond and Phlox divaricata cv. AltMV-LGB JX457330 USA, MD Reinsel, 2015 London Grove Blue Hammond and AltMV-PGL JQ405265 Phlox carolina angusta USA Reinsel, 2015 Portulaca-like isolates Ciufo and Turina, Italy, Liguria, AltMV-IT AY566288 Portulaca grandifora 2004 Albenga Hammond et al., AltMV-Po AY850930 Portulaca grandifora USA, MD 2004,2006a,b South-Eastern AltMV-MU FJ822136 Ivanov et al.,2011 Portulaca grandifora Europe Hammond and AltMV-Port JQ405269 Portulaca grandifora USA Reinsel, 2015 Hammond and AltMV-PLR JQ405266 Phlox hybrid (annual) USA Reinsel, 2015 Hammond and AltMV-CIN JQ405268 Pericallis hybrid USA Reinsel, 2015 Asian isolate AltMV-0c LC107515 Iwabuchi et al., 2016 Achyranthes bidentata Japan, Tokyo Unassigned isolates Portulaca sp. AltMV Florida Scutellaria longifolia DQ393785 Baker et al., 2006 USA, FL isolate Crossandra infundibuliformis FJ232066, AltMV-f Duarte et al., 2008 Torenia sp. Brazil, Sao˜ Paulo FJ232067 AltMV Lockhart and EU679363 Angelonia angustifolia USA, NY angelonia isolate Daughtrey, 2008 AltMV isolate JQ687034 Vitoreli et al.,2011 Tunbergia laurifolia USA, FL G10-00982 diverged groups within the AltMV taxon [11, 20]. Based on AltMV-IT, AltMV-MU, AltMV-Port, AltMV-Po, AltMV- amino acid sequences of RNA-dependent RNA polymerase CIN, and AltMV-PLR (Table 1) were classifed as portulaca- (RdRp, replicase) and CP,Ivanov et al. [11] have distinguished like isolates [20]. Ivanov et al. [11] indicated a close evolu- 2 groups within the AltMV species: phlox-like isolates and tionary relationship among the isolates of this group. Te portulaca-likeisolates.InthestudybyHammondandReinsel amino acid sequences of AltMV-IT, AltMV-MU, and AltMV- [20] this diferentiation was confrmed by means of amino Po CPs difer on substitutions at two sites, methionine acid sequence analysis of the three proteins which are 106 for isoleucine and serine 185 for phenylalanine [11]. products of the “triple gene block” (TGB). Apparently, Asian AltMV-Au, AltMV-PA, AltMV-NAN, and AltMV-SP were AltMV isolate should be regarded as a separate group [18]. classifed as phlox-like isolates. Belonging to diferent groups, Advances in Virology 3 theCPsofAltMV-MUandAltMV-PAarediferentby12 rugosity, veinal necrosis, and interveinal yellowing (Table 2) amino acid residues situated mainly on the N-terminus [1,2,12,15,17]. of CP [11]. Nucleotide sequences determined for AltMV AltMV infection symptoms were shown to depend not isolates obtained from Scutellaria longifolia [12], Torenia [17], only on the host plant species, but also on the duration of Angelonia angustifolia [15], and Tunbergia laurifolia plants infection, virus strain, and environmental factors. For exam- [21] are too short for detailed analysis, yet most likely they ple, symptoms being mostly pronounced in plants grown belong to portulaca-like type [20]. under high light levels and moderate temperature escaped Te reported distribution of isolates may be determined notice in plants grown under low light levels and high temper- by the peculiarities of the host plant cultivation. Annual ature [2]. For AltMV-SP isolates derived from tobacco Nico- phlox, cineraria, angelonia, torenia, thunbergia, and portu- tiana benthamiana the symptom severity was shown to cor- laca are grown mostly in greenhouses as ornamental plants, relate with sequence diferences of the replicase (RdRp) and while perennial phlox and nandina with vegetative repro- Triple Gene Block protein 1 (TGBp1) [23]. Similarly, in case duction are cultivated in open ground. Similar conditions of AltMV-Po isolate, the level of severity in symptom mani- of plant cultivation most likely account for portulaca-like festationwasdemonstratedtogohandinhandwithchanges AltMV detection in greenhouse plants; moreover, portulaca in amino acid sequence of CP [24]. mighthaveservedasaninfectionsourceforthistype Te ability of AltMV to infect a wide host range leading of horticulture. Similarly, the spread of phlox-like AltMV to symptomless infection allows for cross-contamination obtained from plants cultivated in open ground was the result among various species including the cultivated ones. Taking of cross-contamination from infected perennial phlox plants the aforementioned into account, AltMV may be more [20]. widespread than the literature suggests, particularly in nurs- According to serological data as well as nucleotide and eries [12, 20]. amino acid sequence similarity, AltMV is the closest relative of the papaya mosaic virus (PapMV) [1, 2, 20]. AltMV is 4. AltMV Propagation and Purification easily confused with PapMV based on serological analysis or PCR analysis in case of an incorrect primer selection Several methods were developed for AltMV isolation from [2] which leads to AltMV being misinterpreted as PapMV a variety of host plants (Table 3). Geering and Tomas [1] [12, 22]. Hammond et al. [2] argued that AltMV is far followed the procedure previously described by Bancrof et more widespread than