Interference of Long-Distance Movement of Grapevine berry inner necrosis virus in Transgenic Plants Expressing a Defective Movement Protein of Apple chlorotic leaf spot virus

Abstract

Transgenic Nicotiana occidentalis plants expressing a movement protein (P50) and partially functional deletion mutants (DeltaA and DeltaC) of the Apple chlorotic leaf spot virus (ACLSV) showed resistance to Grapevine berry inner necrosis virus (GINV). The resistance is highly effective and GINV was below the level of detection in both inoculated and uninoculated upper leaves. In contrast, GINV accumulated in inoculated and uninoculated leaves of nontransgenic (NT) plants and transgenic plants expressing a dysfunctional mutant (DeltaG). On the other hand, in some plants of a transgenic plant line expressing a deletion mutant (DeltaA', deletion of the C-terminal 42 amino acids), GINV could spread in inoculated leaves, but not move into uninoculated leaves. In a tissue blot hybridization analysis of DeltaA'-plants inoculated with GINV, virus could be detected in leaf blade, midribs, and petiole of inoculated leaves, but neither in stems immediately above inoculated leaves nor in any tissues of uninoculated leaves. Immunohistochemical analysis of GINV-inoculated leaves of DeltaA'-plants showed that GINV could invade into phloem parenchyma cells through bundle sheath of minor veins, suggesting that the long-distance transport of GINV might be inhibited between the phloem cells and sieve element (and/or within sieve element) rather than bundle sheath-phloem interfaces. Immunogold electron microscopy using an anti-P50 antiserum showed that P50 accumulated on the parietal layer of sieve elements and on sieve plates. The results suggested that resistance in P50-transgenic plants to GINV is due to the interference of both long-distance and cell-to-cell movement of the virus.

Biotechnological approaches for plant viruses resistance: from general to the modern RNA silencing pathway

“…Transgenic plants that contain mutant MPs from PMV show resistance to several TMVs as well as to AIMV, Cauliflower mosaic virus (CaMV) and other viruses (Cooper et al, 1995). Similar results were found for Nicotiana occidentalis plants expressing a movement protein (P50) and partially functional deletion mutants (DeltaA and DeltaC) of the Apple chlorotic leaf spot virus (ACLSV) showed resistance to Grapevine berry inner necrosis virus (GINV) (Yoshikawa et al, 2006). The use of mutated MPs could, therefore, lead to transgenic plants that efficiently inhibit the local and systemic spread of many different viruses.…”

Apple chlorotic leaf spot virus 50 kDa movement protein acts as a suppressor of systemic silencing without interfering with local silencing in Nicotiana benthamiana

“…ACLSV P50 is a movement protein (MP) that has the following features: (i) it localizes to plasmodesmata of infected cells and in cells expressing P50 from a transgene, and also accumulates in the parietal layer of sieve elements and on sieve plates (Yoshikawa et al, 1999(Yoshikawa et al, , 2006; (ii) it can spread from cells that initially produce it into neighbouring cells (Satoh et al, 2000); (iii) it enables cell-to-cell trafficking of GFP when P50 and GFP are co-expressed in leaf DSystemic silencing for these eight plants was restricted to the regions on and around the veins of a few leaves, as shown in Fig. 3[a(iv-b)].…”

“…epidermis (Satoh et al, 2000); (iv) it induces the production of tubular structures protruding from the surface of protoplasts (Satoh et al, 2000;Isogai et al, 2003); (v) it has two independently active, single-stranded nucleic acidbinding domains (Isogai & Yoshikawa, 2005); and (vi) it interferes specifically with the functions of the MP encoded by Grapevine berry inner necrosis virus (Isogai et al, 2003;Yoshikawa et al, 2000Yoshikawa et al, , 2006. In addition, the present study indicates that P50 functions as a suppressor of RNA silencing.…”

Molecular Biology in Plant Pathogenesis and Disease Management

“…Accumulation of p50 on the parietal layer of sieve elements and on sieve plates, was revealed by immunogold electron microscopy using an anti-P50 antiserum. Interference of both cell-to-cell and long-distance movements of the virus may contribute to the resistance to GINV in N. occidentalis (Yoshikawa et al 2006).…”