Outbreak of cucumber mosaic virus subgroup IB in pepper from the Espelette area (Basque Country, southwestern France) and first report of five taxa as natural hosts of CMV.

To better understand the emergence of cucumber mosaic virus (CMV) in the protected designation of origin of Espelette pepper (southwestern France), more than 7,300 samples were collected in and around 36 pepper fields in 2021 and 2022, and diagnosed using ELISA, RT-PCR and partial Sanger sequencing of viral RNAs. This allowed the identification of five new host genera or species among the natural hosts of CMV: Arum italicum, Cerastium glomeratum, Hyacinthoides sp., Lysimachia arvensis and Trifolium incarnatum.

Absence of Seed-Mediated Transmission of Cucumber Mosaic Virus in Espelette Pepper Crops despite Widespread and Recurrent Epidemics.

In the past decade, severe epidemics of cucumber mosaic virus (CMV) have caused significant damage to Espelette pepper crops. This virus threatens the production of Espelette pepper, which plays a significant role in the local economy and touristic attractiveness of the French Basque Country, located in southwestern France. In 2021 and 2022, CMV was detected via double-antibody sandwich enzyme-linked immunosorbent assays (DAS-ELISAs) in Gorria pepper seed lots harvested from naturally infected fields scattered throughout the entire Espelette pepper production area.

Biological and Genetic Characterization of Physostegia Chlorotic Mottle Virus in Europe Based on Host Range, Location, and Time.

Application of high throughput sequencing (HTS) technologies enabled the first identification of Physostegia chlorotic mottle virus (PhCMoV) in 2018 in Austria. Subsequently, PhCMoV was detected in Germany and Serbia on tomatoes showing severe fruit mottling and ripening anomalies. We report here how prepublication data-sharing resulted in an international collaboration across eight laboratories in five countries, enabling an in-depth characterization of PhCMoV.

Specificity of Resistance and Tolerance to Cucumber Vein Yellowing Virus in Melon Accessions and Resistance Breaking with a Single Mutation in VPg.

Cucumber vein yellowing virus (CVYV) is an emerging virus on cucurbits in the Mediterranean Basin, against which few resistance sources are available, particularly in melon. The melon accession PI 164323 displays complete resistance to isolate CVYV-Esp, and accession HSD 2458 presents a tolerance, i.e.

Can Winged Aphid Abundance Be a Predictor of Cucurbit Aphid-Borne Yellows Virus Epidemics in Melon Crop?

Aphid-borne viruses are frequent yield-limiting pathogens in open field vegetable crops. In the absence of curative methods, virus control relies exclusively on measures limiting virus introduction and spread. The efficiency of control measures may greatly benefit from an accurate knowledge of epidemic drivers, in particular those linked with aphid vectors.

Distribution and evolution of the major viruses infecting cucurbitaceous and solanaceous crops in the French Mediterranean area.

Plant viral diseases represent a significant burden to plant health, and their highest impact in Mediterranean agriculture is on vegetables grown under intensive horticultural practices. In order to understand better virus evolution and emergence, the most prevalent viruses were mapped in the main cucurbitaceous (melon, squashes) and solanaceous (tomato, pepper) crops and in some wild hosts in the French Mediterranean area, and virus diversity, evolution and population structure were studied through molecular epidemiology approaches. Surveys were performed in summer 2016 and 2017, representing a total of 1530 crop samples and 280 weed samples.

Resistance Against Melon Chlorotic Mosaic Virus and Tomato Leaf Curl New Delhi Virus in Melon.

Thirty-one melon accessions were screened for resistance to the begomoviruses (MeCMV) and (ToLCNDV). Five accessions presented nearly complete resistance to both viruses. Accession IC-274014, showing the highest level of resistance to both viruses, was crossed with the susceptible cultivar Védrantais.

Impact of Vat resistance in melon on viral epidemics and genetic structure of virus populations.

Cultivar choice is at the heart of cropping systems and resistant cultivars should be at the heart of disease management strategies whenever available. They are the easiest, most efficient and environmentally friendly way of combating viral diseases at the farm level. Among the melon genetic resources, Vat is a unique gene conferring resistance to both the melon aphid Aphis gossypii and the viruses it carries.

Sequencing viral siRNAs to identify previously undescribed viruses and viroids in a panel of ornamental plant samples structured as a matrix of pools.

Ornamental plants constitute a largely unknown and potentially important source of pathogens affecting not only ornamental plants, but also major crop species. We have carried out studies using high-throughput sequencing of 21-24 nt RNAs from potentially virus-infected ornamental plants, followed by assembly of sequence scaffolds, to identify the virus and viroid genomes present in a panel of 67 plant samples representing 46 species belonging to the main sectors of the ornamental plant industry (cut flowers, pot plants, bulbs). A pilot study demonstrated that samples could be pooled (5 samples per pool), and the overall process simplified without loss of detection of important known pathogens.

Characterization of a new cucurbit-infecting ipomovirus from Sudan.

Two members of the genus Ipomovirus (family Potyviridae) are known to infect cucurbits: cucumber vein yellowing virus (CVYV), which is emerging throughout the Mediterranean Basin, and squash vein yellowing virus (SqVYV), which has been described in America and the Caribbean Basin, and more recently in Israel. In this work, an ipomovirus different from CVYV and SqVYV, tentatively named coccinia mottle virus (CocMoV), was detected in a sample of the cucurbit Coccinia grandis collected in central Sudan in 2012. Sequence identity in nt was 68 % with CVYV, 59-60 % with SqVYV, cassava brown streak virus and Ugandan cassava brown streak virus, and less than 50 % with other members of the family Potyviridae.

Snake melon asteroid mosaic virus, a Tentative New Member of the Genus Sobemovirus Infecting Cucurbits.

A virus isolate (Su-95-67) was obtained from a snake melon (Cucumis melo var. flexuosus) plant presenting severe chlorotic spots, mosaic, stunting, and leaf deformations collected in Eastern Sudan in 1995. Su-95-67 was easily mechanically transmissible and had a host range limited to a few cucurbit species.

Potential Involvement of Melon Fruit in the Long Distance Dissemination of Cucurbit Potyviruses.

Papaya ringspot virus (PRSV) and Zucchini yellow mosaic virus(ZYMV) are potyviruses frequently reported in cucurbits in Mediterranean, subtropical, and tropical regions. Occasionally, epidemics are also observed in more temperate regions, but the ways these viruses are introduced into new areas are not yet fully determined. We investigated the possibility that infected imported melon fruit could be a route for the introduction of PRSV and ZYMV.

Biological and Molecular Characterization of Moroccan watermelon mosaic virus and a Potyvirus Isolate from Eastern Sudan.

A potyvirus (Su-94-54) was isolated from a naturally infected snake cucumber (Cucumis melo var. flexuosus) plant with severe mosaic and leaf deformation symptoms collected in Eastern Sudan. This isolate has a host range limited to cucurbits and is serologically distantly related to Moroccan watermelon mosaic virus (MWMV) and to Papaya ringspot virus (PRSV).

Melon Rugose Mosaic Virus: Characterization of an Isolate from Sudan and Seed Transmission in Melon.

Melon rugose mosaic virus (MRMV) was isolated from snake cucumber (Cucumis melo var. flexuosus) in the Kassala region of Sudan in 1993. The host range of the virus was mostly limited to cucurbits, where it induced severe mosaic and leaf deformations.