Genetic Diversity of Grapevine Virus A in Three Australian Vineyards Using Amplicon High Throughput Sequencing (Amplicon-HTS).

Shiraz disease (SD) is one of the most destructive viral diseases of grapevines in Australia and is known to cause significant economic loss to local growers. Grapevine virus A (GVA) was reported to be the key pathogen associated with this disease. This study aimed to better understand the diversity of GVA variants both within and between individual SD and grapevine leafroll disease (LRD) affected grapevines located at vineyards in South Australia.

State-of-the-Art Plant Virus Research in Australasia.

The Special Issue 'State-of-the-Art Plant Virus Research in Australasia' in provided a fascinating snapshot of plant and fungus virus research being undertaken in Australasia during the final year of the official COVID-19 pandemic [...

A Chronological Study on Grapevine Leafroll-Associated Virus 2 in Australia.

Grapevine leafroll disease affects the health status of grapevines worldwide. Most studies in Australia have focused on grapevine leafroll-associated viruses 1 and 3, while little attention has been given to other leafroll virus types, in particular, grapevine leafroll-associated virus 2 (GLRaV-2). A chronological record of the temporal occurrence of GLRaV-2 in Australia since 2001 is reported.

The ABI5-dependent down-regulation of mitochondrial ATP synthase OSCP subunit facilitates apple necrotic mosaic virus infection.

Apple necrotic mosaic virus (ApNMV) is associated with apple mosaic disease in China. However, the mechanisms of ApNMV infection, as well as host defence against the virus, are still poorly understood. Mitochondrial ATP synthase plays a fundamental role in the regulation of plant growth and development.

A Metagenomic Investigation of the Viruses Associated with Shiraz Disease in Australia.

Shiraz disease (SD) is an economically important virus-associated disease that can significantly reduce yield in sensitive grapevine varieties and has so far only been reported in South Africa and Australia. In this study, RT-PCR and metagenomic high-throughput sequencing was used to study the virome of symptomatic and asymptomatic grapevines within vineyards affected by SD and located in South Australia. Results showed that grapevine virus A (GVA) phylogroup II variants were strongly associated with SD symptoms in Shiraz grapevines that also had mixed infections of viruses including combinations of grapevine leafroll-associated virus 3 (GLRaV-3) and grapevine leafroll-associated virus 4 strains 5, 6 and 9 (GLRaV-4/5, GLRaV-4/6, GLRaV-4/9).

Identification and molecular characterization of a novel carlavirus infecting rose plants (Rosa chinensis Jacq.).

In the present study, the genome sequence of a potential novel virus, tentatively named "rose virus C" (RVC), was mined from publically available transcriptomic data from a Rosa chinensis plant. The complete genome sequence of RVC consists of 8,386 nt, excluding a 3' poly(A) tail, and contains five ORFs. Phylogenetic analysis showed that RVC clustered with members of the genus Carlavirus, family Betaflexiviridae.

Molecular characterization of rose spring dwarf-associated virus isolated from China rose (Rosa chinensis Jacq.) in China.

China rose (Rosa chinensis Jacq.) is an important ornamental plant grown widely in China. In May 2019, we sampled and analyzed a China rose plant by high-throughput sequencing using small RNAs.

Molecular characterization and pathogenicity analysis of prunus necrotic ringspot virus isolates from China rose (Rosa chinensis Jacq.).

Prunus necrotic ringspot virus (PNRSV) is a viral pathogen with worldwide distribution, infecting many commercial fruit trees and ornamental plants. So far, the correlation between PNRSV infection and China rose mosaic disease has not been studied. Rose mosaic disease is characterized by severe symptoms, including mosaic, line pattern, and ringspot.

Virus Pathogens in Australian Vineyards with an Emphasis on Shiraz Disease.

Grapevine viruses are found throughout the viticultural world and have detrimental effects on vine productivity and grape and wine quality. This report provides a comprehensive and up-to-date review on grapevine viruses in Australia with a focus on "Shiraz Disease" (SD) and its two major associated viruses, grapevine virus A (GVA) and grapevine leafroll-associated virus 3 (GLRaV-3). Sensitive grapevine cultivars like Shiraz infected with GVA alone or with a co-infection of a leafroll virus, primarily GLRaV-3, show symptoms of SD leading to significant yield and quality reductions in Australia and in South Africa.

Characterization of grapevine leafroll-associated virus 3 genetic variants and application towards RT-qPCR assay design.

Grapevine leafroll-associated virus 3 (GLRaV-3) is the most widely prevalent and economically important of the complex of RNA viruses associated with grapevine leafroll disease (GLD). Phylogenetic studies have grouped GLRaV-3 isolates into nine different monophyletic groups and four supergroups, making GLRaV-3 a genetically highly diverse virus species. In addition, new divergent variants have been discovered recently around the world.

Complete nucleotide sequence of a new virus, peach chlorotic leaf spot virus, isolated from flat peach in China.

Contigs with sequence homologies to apple chlorotic leaf spot virus (ACLSV) were identified by high-throughput sequencing analysis in three peach samples. Complete genomic sequences of RP19-1 and RP19-2 of the virus consisted of 7,466 and 7,465 nucleotides (nts), respectively, excluding the poly (A) tails. They shared the highest identity with Ta Tao 5, but lower than 70% of sequence similarity with other ACLSV isolates.

Improved detection of grapevine latent viroid by RT-qPCR, its bioassay analysis, and its rare occurrence worldwide.

Three of the five well-known viroids infecting grapevine belong to the genus Apscaviroid. Grapevine latent viroid (GLVd) is a novel grapevine viroid. Although GLVd has the typical sequence motifs of the genus Apscaviroid, it is still an unassigned viroid.

The recent importation of Grapevine Pinot gris virus into Australia.

A total of 575 commercial grapevine (Vitis vinifera) samples from Australia have been tested for a newly emerging virus, Grapevine Pinot gris virus (Trichovirus, Betaflexiviridae) during 2015-2017. Nine samples from two states tested positive. Six of these were from New South Wales and 3 from South Australia in a total of eight varieties.

Effect of temperature on symptom expression and sequence polymorphism of grapevine yellow speckle viroid 1 in grapevine.

Symptom expression of yellow speckle disease was studied in a row of 32 individual Vitis vinifera cv. Chardonnay vines in the warmer summer of 2009/2010 as compared with the cooler summer of 2011/2012 in South Australia. RT-PCR analysis showed that all these vines were positive for hop stunt viroid, grapevine yellow speckle viroid 1 (GYSVd-1) and grapevine rupestris stem pitting-associated virus.

New Iranian and Australian peach latent mosaic viroid variants and evidence for rapid sequence evolution.

Peach latent mosaic viroid isolates from peach and plum in Iran have been compared with an Australian isolate from nectarine. Thirteen sequence variants 336-338 nt in size were obtained. All variants clustered phylogenetically with variants reported from several hosts and countries.

Extensive variation of sequence within isolates of Grapevine virus B+.

Four regions covering 1247 nucleotides of the RNA genome of 20 isolates of a Vitivirus, Grapevine virus B (GVB), from three countries were analyzed. All the regions in these isolates varied in sequence as compared to the published GVB sequence. Of these, the intergenic region varied the most, with 73.

Temporal and Spatial Analysis of Grapevine Leafroll-Associated Virus 3 in Pinot Noir Grapevines in Australia.

An epidemic of grapevine leafroll disease (GLD), caused by grapevine leafroll-associated virus 3 (GLRaV-3), was monitored over an 11-year period in Nuriootpa, South Australia. Inoculum originated from infected budwood, and initial GLD incidence at the time of transplanting in 1986 was 23.1%.