Systemic Propagation of a Fluorescent Infectious Clone of a Polerovirus Following Inoculation by Agrobacteria and Aphids

Abstract

A fluorescent viral clone of the polerovirus Turnip yellows virus (TuYV) was engineered by introducing the Enhanced Green Fluorescent Protein (EGFP) sequence into the non-structural domain sequence of the readthrough protein, a minor capsid protein. The resulting recombinant virus, referred to as TuYV-RTGFP, was infectious in several plant species when delivered by agroinoculation and invaded efficiently non-inoculated leaves. As expected for poleroviruses, which infect only phloem cells, the fluorescence emitted by TuYV-RTGFP was restricted to the vasculature of infected plants. In addition, TuYV-RTGFP was aphid transmissible and enabled the observation of the initial sites of infection in the phloem after aphid probing in epidermal cells. The aphid-transmitted virus moved efficiently to leaves distant from the inoculation sites and importantly retained the EGFP sequence in the viral genome. This work reports on the first engineered member in the Luteoviridae family that can be visualized by fluorescence emission in systemic leaves of different plant species after agroinoculation or aphid transmission.

Are Cerium Oxide Nanoparticles Transferred from Plants to the Aphid Myzus persicae (Hemiptera: Aphididae)?

“…A second possible Ce pathway is based on previous studies involving the transport of particles through the gut wall to the hemocoel, which commonly occurs with viruses (Brault et al 2007;Tamborindeguy et al 2010). Although most of the aphid-transmitted plant viruses are 20 to 25 nm wide (Sicard et al 2015;Boissinot et al 2017), which is about one-tenth the diam of nano-CeO 2 clusters, this transport is performed by transcytosis (endocytosis/exocytosis) (Seddas et al 2004), and involves specific receptors. In this respect, nano-CeO 2 could cause histological changes in the tissues of M. persicae, similar to what was reported in a study performed with the worm Eisenia fetida (Savigny) (Annelida: Lumbricidae) (Lahive et al 2014), resulting in absorption and transport.…”

Co-Acquired Nanovirus and Geminivirus Exhibit a Contrasted Localization within Their Common Aphid Vector

“…Veins from the upper leaves of infected plants were collected with an adhesive tape following a published protocol [25]. The veins were then fixed overnight at 4 • C under gentle stirring in embryo dishes containing 4% paraformaldehyde (PFA) and 0.2% Triton X-100 diluted in phosphate-buffered saline 1X pH 7.4 (PBS).…”

Phloem-Triggered Virus-Induced Gene Silencing Using a Recombinant Polerovirus

“…Since stable virions are required for TuYV systemic spread in Nicotiana species ( Brault et al, 2003 ) and in A. thaliana plants ( Hipper et al, 2014 ), the genome size constraint imposed for the formation of stable isometric particles was taken into consideration in the design of the TuYV-based VIGS vectors. Previous studies have shown that inserting long foreign sequences in the genome of poleroviruses could be detrimental to genome stability, systemic movement or aphid transmission of the resulting viruses ( Nurkiyanova et al, 2000 ; Boissinot et al, 2017 ). In particular the genome integrity of TuYV was seriously affected in A. thaliana ( Boissinot et al, 2017 ).…”

“…Previous studies have shown that inserting long foreign sequences in the genome of poleroviruses could be detrimental to genome stability, systemic movement or aphid transmission of the resulting viruses ( Nurkiyanova et al, 2000 ; Boissinot et al, 2017 ). In particular the genome integrity of TuYV was seriously affected in A. thaliana ( Boissinot et al, 2017 ). Furthermore most of the viral proteins encoded by TuYV are required to establish an efficient systemic proliferation and promote aphid transmission ( Brault et al, 1995 ; Ziegler-Graff et al, 1996 ; Bruyère et al, 1997 ; Rodriguez-Medina et al, 2015 ; Smirnova et al, 2015 ).…”

“…This is likely due to genome size constraints to package appropriately the viral genome into icosahedral particles. Only very recently Boissinot et al (2017) obtained a recombinant polerovirus derived from Turnip yellows virus (TuYV) expressing EGFP in fusion with the non-structural domain of the readthrough protein. TuYV-EGFP virus was visualized by fluorescence in the vasculature of infected plants.…”