Characterization of Grapevine Fanleaf Virus Isolates in ‘Chardonnay’ Vines Exhibiting Severe and Mild Symptoms in Two Vineyards

Abstract

Fanleaf degeneration is a complex viral disease of Vitis spp. that detrimentally impacts fruit yield and reduces the productive lifespan of most vineyards worldwide. In France, its main causal agent is grapevine fanleaf virus (GFLV). In the past, field experiments were conducted to explore cross-protection as a management strategy of fanleaf degeneration, but results were unsatisfactory because the mild virus strain negatively impacted fruit yield. In order to select new mild GFLV isolates, we examined two old ‘Chardonnay’ parcels harbouring vines with distinct phenotypes. Symptoms and agronomic performances were monitored over the four-year study on 21 individual vines that were classified into three categories: asymptomatic GFLV-free vines, GFLV-infected vines severely diseased and GFLV-infected vines displaying mild symptoms. The complete coding genomic sequences of GFLV isolates in infected vines was determined by high-throughput sequencing. Most grapevines were infected with multiple genetically divergent variants. While no specific molecular features were apparent for GFLV isolates from vines displaying mild symptoms, a genetic differentiation of GFLV populations depending on the vineyard parcel was observed. The mild symptomatic grapevines identified during this study were established in a greenhouse to recover GFLV variants of potential interest for cross-protection studies.

Profiling Plant Proteome and Transcriptome Changes during Grapevine Fanleaf Virus Infection

“…The disparate ratio of GFLV RNA molecules and departure of the viral titer related to symptomology were previously documented for Vitis vinifera cv. “Chardonnay” in a vineyard setting . This RNA ratio was also recently documented for tobacco ringspot virus and tomato ringspot virus (ToRSV), two nepoviruses related to GFLV, in pawpaw, another fruit crop …”

“…"Chardonnay" in a vineyard setting. 71 This RNA ratio was also recently documented for tobacco ringspot virus and tomato ringspot virus (ToRSV), two nepoviruses related to GFLV, in pawpaw, another fruit crop. 72 Some parallels can be made between our findings on GFLV and other nepoviruses such as ToRSV 73,74 and artichoke Italian latent virus (AILV).…”

“…“Chardonnay” in a vineyard setting. 71 This RNA ratio was also recently documented for tobacco ringspot virus and tomato ringspot virus (ToRSV), two nepoviruses related to GFLV, in pawpaw, another fruit crop. 72 …”

Grapevine Virome of the Don Ampelographic Collection in Russia Has Concealed Five Novel Viruses

“…Grapevine Fanleaf Virus GFLV (genus Nepovirus) is one of the most harmful viral pathogens of grapevine [23,53]. It is responsible for fanleaf degeneration disease, the losses from which can reach up to 80% of the crop [54].…”