Search Results (2)

Viruses are trailblazers in hijacking host systems for their own needs. Plant viruses have been shown to exploit alternative avenues of translocation within a host, including a challenging route through the xylem, to expand their niche and establish systemic spread, despite apparent host-imposed obstacles. Recent findings indicate that plant viruses from many families could successfully hack xylem cells in a broad range of plant hosts, including herbaceous and perennial woody plants. Similar to virus-related structures present in the phloem, virus particles and membrane-containing viral replication complexes are often observed in the xylem. Except for a few single-stranded DNA viruses in the family Geminiviridae and a negative-sense single-stranded RNA rhabdovirus, Lettuce necrotic yellows virus, the majority of the viruses that were detected in the xylem belong to the group of positive-sense RNA viruses. The diversity of the genome organization and virion morphology of those viruses indicates that xylem exploitation appears to be a widely adapted strategy for plant viruses. This review outlines the examples of the xylem-associated viruses and discusses factors that regulate virus inhabitation of the xylem as well as possible strategies of virus introduction into the xylem. In some cases, plant disease symptoms have been shown to be closely related to virus colonization of the xylem. Inhibiting viral xylem invasion could raise potential attractive approaches to manage virus diseases. Therefore, the identification of the host genes mediating virus interaction with the plant xylem tissue and understanding the underlying mechanisms call for more attention. Full article

Lettuce necrotic yellows virus is a type of species in the Cytorhabdovirus genus and appears to be endemic to Australia and Aotearoa New Zealand (NZ). The population of lettuce necrotic yellows virus (LNYV) is made up of two subgroups, SI and SII. Previous studies demonstrated that SII appears to be outcompeting SI and suggested that SII may have greater vector transmission efficiency and/or higher replication rate in its host plant or insect vector. Rhabdovirus glycoproteins are important for virus–insect interactions. Here, we present an analysis of LNYV glycoprotein sequences to identify key features and variations that may cause SII to interact with its aphid vector with greater efficiency than SI. Phylogenetic analysis of glycoprotein sequences from NZ isolates confirmed the existence of two subgroups within the NZ LNYV population, while predicted 3D structures revealed the LNYV glycoproteins have domain architectures similar to Vesicular Stomatitis Virus (VSV). Importantly, changing amino acids at positions 244 and 247 of the post-fusion form of the LNYV glycoprotein altered the predicted structure of Domain III, glycosylation at N248 and the overall stability of the protein. These data support the glycoprotein as having a role in the population differences of LNYV observed between Australia and New Zealand. Full article