Estimation of the functions of viral RNA silencing suppressors by apple latent spherical virus vector
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Apple latent spherical virus (ALSV) is a latent virus with wide host range of plant species. In the present study, we prepared ALSV vectors expressing RNA silencing suppressors (RSSs) from eight plant viruses: P19 of carnation Italian ring spot virus (tombusvirus), 2b of peanut stunt virus (cucumovirus), NSs of tomato spotted wilt virus (tospovirus), HC-Pro of bean yellow mosaic virus (potyvirus), γb of barley stripe mosaic virus (hordeivirus), P15 of peanut clump virus (pecluvirus), P1 of rice yellow mottle virus (sobemovirus), or P21 of beet yellows virus (closterovirus). These vectors were inoculated to Nicotiana benthamiana to investigate the effects of RSSs on the virulence and accumulation of ALSV. Among the vectors, ALSV expressing NSs (ALSV-NSs) developed severe mosaic symptoms in newly developed leaves followed by plant death. Infection of ALSV-γb induced characteristic concentric ringspot symptoms on leaves, and plants infected with ALSV-HC-Pro showed mosaic and dwarf symptoms. Infection of the other five ALSV vectors did not show symptoms. ELISA and immunoblot assay indicated that virus titer increased in leaves infected with ALSV-NSs, γb, HC-Pro, or P19. RT-qPCR indicated that the amount of ALSV in plants infected with ALSV-NSs was increased by approximately 45 times compared with that of wtALSV without expression of any RSS. When ALSV-P19, NSs, or HC-Pro was inoculated to Cucumis sativus plants, none of these ALSV vectors induced symptoms, but accumulation of ALSV in plants infected with ALSV-NSs was increased, suggesting that functions of RSSs on virulence and accumulation of ALSV depend on host species.
KeywordsApple latent spherical virus RNA silencing suppressor Viral symptoms Viral accumulation
This work was supported by the Programme for Promotion of Basic and Applied Researches for Innovations in Bio-oriented Industry from the Ministry of Agriculture, Forestry, and Fisheries, Japan
CL and NY designed the study; CL and MI performed the experiments; IK analyzed the data; CL, IK, and NY drafted the manuscript; and all authors approved the final version.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflicts of interest with respect to the data, authorship, or publication of this article.
Research involving in human and animal participants
This article does not contain any experiments with human participants or animals performed by any of the authors and is in compliance with ethical standards for research.
- 12.Fagoaga C, Pensabene-Bellavia G, Moreno P, Navarro L, Flores R, Peña L (2011) Ectopic expression of the p23 silencing suppressor of Citrus tristeza virus differentially modifies viral accumulation and tropism in two transgenic woody hosts. Mol Plant Pathol 12:898–910PubMedPubMedCentralGoogle Scholar
- 15.Igarashi A, Yamagata K, Sugai T, Takahashi Y, Sugawara E, Tamura A, Yaegashi H, Yamagishi N, Takahashi T, Isogai M, Takahashi H, Yoshikawa N (2009) Apple latent spherical virus vectors for reliable and effective virus-induced gene silencing among a broad range of plants including tobacco, tomato, Arabidopsis thaliana, cucurbits, and legumes. Virology 386:407–416PubMedGoogle Scholar
- 16.Kasajima I, Ito M, Yamagishi N, Yoshikawa N (2017) Apple latent spherical virus (ALSV) vector as a tool for reverse genetic studies and non-transgenic breeding of a variety of crops. In: Rajewsky N, Jurga S, Barciszewski J (eds) Plant epigenetics. Springer, Cham, pp 513–536Google Scholar
- 19.Kawai T, Gonoi A, Nitta M, Kaido M, Yamagishi N, Yoshikawa N, Tao T (2014) Virus-induced genes silencing in Apricot (Prunus armeniaca L.) and Japanese apricot (P. mume Siebold & Zucc.) with Apple latent spherical virus vector system. J Jpn Soc Hortic Sci 83:23–31Google Scholar
- 29.Nakamura K, Yamagishi N, Isogai M, Komori S, Ito T, Yoshikawa N (2011) Seed and pollen transmission of Apple latent spherical virus in apple. J Gen Plant Pathol 77:48–53Google Scholar
- 31.Okuda M, Taba S, Hanada K (2003) The S RNA segment determines symptom differences on Tetragonia expansa between two Watermelon silver mottle virus isolates. Physiol Mol Plant Pathol 62:327–332Google Scholar
- 40.Senanayake DM, Mandal B (2014) Expression of symptoms, viral coat protein and silencing suppressor gene during mixed infection of a N-Wi strain of potato virus Y and an asymptomatic strain of potato virus X. Virus Dis 25:314–321Google Scholar
- 57.Yamagishi N, Sasaki S, Yamagata K, Komori S, Nagase M, Wada M, Yamamoto T, Yoshikawa N (2011) Promotion of flowering and reduction of a generation time in apple seedlings by ectopical expression of the Arabidopsis thaliana FT gene using the Apple latent spherical virus vector. Plant Mol Biol 75:193–204PubMedGoogle Scholar