OCCURRENCE OF TOMATO LEAF CURL NEW DELHI VIRUS INFECTING ZUCCHINI IN SARDINIA (ITALY)

Tomato leaf curl New Delhi virus (ToLCNDV, genus Begomovirus) is a bipartite, circular, ssDNA virus, able to infect species within the Cucurbitaceae and Solanaceae. In August 2016, field observations carried out in Sardinia (Italy) highlighted in one location (Decimoputzu, CA) some plants of zucchini squash (Cucurbita pepo L.) showing a systemic disease never observed before, even in a previous survey (end-June 2016) on cucurbit viruses

First nucleotide sequence of a Carlavirus infecting caper

A carlavirus from asymptomatic caper plants (Capparis spinosa L.), that was provisionally considered a distinct isolate of the previously described Caper latent virus, was partially sequenced. The translated amino acid sequences of the RNA dependent RNA polymerase (RdRp) gene and coat protein (CP) gene were compared with the equivalent sequences of members of the genus Carlavirus. The isolate, named CapLV-L7, showed less than 78% and 72% amino acid identity in RdRp and CP regions, respectively, with the other carlaviruses tested. The closest sequence similarity was with Nerine latent virus and Potato virus M. The phylogenic trees showed a close relationship of CapLV-L7 with Nerine latent virus in both genes

First Report of Tomato Leaf Curl New Delhi Virus Causing Yellow Leaf Curl of Pepper in Europe

Tomato leaf curl New Delhi virus (ToLCNDV), a bipartite begomovirus (family Geminiviridae) with two circular ssDNA genome components (DNA-A and DNA-B), is transmitted in a circulative nonpropagative manner by the whitefly Bemisia tabaci (Gennadius). Although it was first reported in Asia on tomato and other solanaceous crops such as eggplant, potato, and chilli pepper in the Mediterranean basin, this virus was mainly detected on cucurbits and only sporadically on tomato and on two wild solanaceous species, Datura stramonium L. and Solanum nigrum L. (Juárez et al. 2019). In 2018, separate surveys were carried out in protected cultivations of sweet pepper (Capsicum annuum L.) in two Italian regions: Lazio and Campania. The greenhouses were in areas with high density of B. tabaci and where ToLCNDV outbreaks occurred on cucurbits since 2016 (Panno et al. 2019). Some plants showing symptoms of yellowing and leaf curling were found in both regions, whereas fruit symptoms were neither observed nor reported by farmers. This disease syndrome, known as yellow leaf curl disease (YLCD), can be caused in pepper by several begomoviruses, as reported recently in a review listing the viruses causing YLCD in peppers in Thailand (Chiemsombat et al. 2018). Symptomatic leaves were collected during late summer 2018 from different pepper plants as well as from the neighboring zucchini cultivations, showing the typical symptomatology induced by ToLCNDV. Total DNA was extracted (DNeasy Plant Mini kit, Qiagen, Germany), and the presence of ToLCNDV was ascertained by PCR with the specific primers ToLCNDV-CP1 and ToLCNDV-CP2 (Panno et al. 2019; Parrella et al. 2018). ToLCNDV infection was further ascertained in three symptomatic leaf samples from Campania by using specific ToLCNDV ImmunoStrips (Agdia, Elkhart, IN). Successively, one symptomatic pepper sample from each greenhouse was selected and amplified by rolling circle amplification technique (RCA; Inoue-Nagata et al. 2004). The amplicons were cloned, and the DNA-A and DNA-B were full-length sequenced. The sequences were deposited in GenBank NCBI database (MK732932 DNA-A and MK732933 DNA-B, pepper sample from Campania; MK756106 DNA-A and MK756107 DNA-B, pepper sample from Lazio). The RCA analysis was performed also on a ToLCNDV-infected zucchini sample collected in the same area in Lazio region (MK756108 DNA-A and MK756109 DNA-B). The analysis of the ToLCNDV sequences showed a low level of genetic variability between the two pepper isolates from Lazio and Campania regions (rate of substitutions: 0.016 for DNA-A and 0.023 for DNA-B). A high genetic similarity was recorded between the zucchini isolate and both the pepper isolates from Campania (0.019 for DNA-A and 0.023 for DNA-B) and Lazio (0.003 for both DNA-A and B). The three characterized isolates showed a high sequence homology also with both the DNA-A (MH577751 from a melon isolate) and DNA-B (MH577673 from a zucchini isolate) of the ToLCNDV-ES genotype (Fortes et al. 2016), which differed in 15 and 13 nucleotide substitutions from pepper sample from Lazio, 29 and 51 substitutions from Campania sample, and 10 and 5 substitutions from zucchini sample. High homology was also identified compared with the other Spanish isolates collected since the first appearance of the virus (2014) and to the Tunisian (2015) and Moroccan (2018) isolates, confirming the hypothesis that the Mediterranean population of ToLCNDV is highly conserved (Juárez et al. 2019). To our knowledge, this is the first report of ToLCNDV infection on pepper in Europe and indicates that sweet pepper could also act as a reservoir of the virus for further spread to other solanaceous plants and cucurbits

Study on ultra-structural effects caused by Onion yellow dwarf virus infection in ‘Rossa di Tropea’ onion bulb by means of magnetic resonance imaging

\u2018Rossa di Tropea\u2019 onion is a particular pink/red coloured onion cultivated in Calabria region (Southern Italy), representing one of the Italian most important vegetable crops granted with Protected Designation of Origin (PDO) and Protected Geographical Indication (PGI) trademarks. This local cultivar is characterised by a high nutraceutical compounds content showing anti-inflammatory, anti-cholesterol, anticancer and antioxidant properties. As all vegetable crops and Allium spp., \u2018Rossa di Tropea\u2019 onion is affected by several viruses. Among these, the species Onion yellow dwarf virus (OYDV, genus Potyvirus, family Potyviridae), represents the most limiting biotic stress, inducing severe symptoms. OYDV effect on tissues architecture in whole bulbs was investigated using magnetic resonance microimaging (MRI) technique, which allows the interior of samples to be imaged non-invasively and non-destructively and yields quantitative information on physico-chemical parameters describing water mobility (T1 and T2 relaxation times). The use of such tool allowed to determine how OYDV alters plant physiology by inducing water accumulation in bulb tissues as well as causing ultra-structural modifications of cell wall, highlighted by MRI. All these effects resulted in an increase of free water in plant tissues, and consequently relevant water losses during post-harvest storage, seriously affecting bulb quality, marketability and shelf life

Transcriptomic and genomic analysis provides new insights in molecular and genetic processes involved in zucchini ZYMV tolerance

Cucurbita pepo is highly susceptible to Zucchini yellow mosaic virus (ZYMV) and the resistance found in several wild species cannot be considered as complete or broad-spectrum resistance. In this study, a source of tolerance introgressed in C. pepo (381e) from C. moschata, in True French (TF) background, was investigated 12 days post-inoculation (DPI) at transcriptomic and genomic levels

First report of Tomato leaf curl New Delhi virus affecting zucchini squash in an important horticultural area of southern Italy

omato leaf curl New Delhi virus (ToLCNDV) is a bipartite begomovirus (family Geminiviridae) which infects species in the families Cucurbitaceae and Solanaceae (Padidam et al., 1995; Mizutani et al., 2011). Begomoviruses are transmitted by the whitefly Bemisia tabaci in a persistent manner (Rosen et al., 2015). In October 2015, severe symptoms not previously reported by growers in the horticultural area of the Province of Trapani (Sicily, Italy) were observed on zucchini squash (Cucurbita pepo) in open fields. The symptoms included yellow mosaic, severe leaf curling, swelling of veins of young leaves, shortening of internodes, roughness of the skin of fruit and reduced fruit size; the symptoms were reminiscent of those caused by begomoviruses. Total DNA was extracted from young leaves of 22 plants by phenol/chloroform extraction and ethanol precipitation. PCR was performed with the A1F/A1R primer pair (Mizutani et al., 2011) for the DNA-A component and the pair described by Ruiz et al. (2015) for the DNA-B component to amplify a ~1200-bp fragment of DNA-A and a ~890 bp fragment of DNA-B, respectively. All 10 samples were positive by PCR with both primer pairs. No amplification products were obtained using primers specific for the monopartite begomoviruses Tomato yellow leaf curl virus and Tomato yellow leaf curl Sardinia virus (Davino et al., 2008). DAS-ELISA analysis for Cucumber mosaic virus, Papaya ring spot virus and Zucchini yellow mosaic virus (Loewe Phytodiagnostica, Germany) yielded negative results

Rapid identification of Trialeurodes vaporariorum, Bemisia tabaci (MEAM1 and MED) and tomato-infecting criniviruses in whiteflies and in tomato leaves by real-time reverse transcription-PCR assay

Abstract The whiteflies Bemisia tabaci and Trialeurodes vaporariorum (Hemiptera Aleyrodidae) are harmful pests of vegetable and ornamental crops in many countries. Also, they are vectors of emergent viruses on tomato including the criniviruses (Closteroviridae genus Crinivirus) Tomato chlorosis virus (ToCV) and Tomato infectious chlorosis virus (TICV). Since different vectors are involved in the transmission of both viruses (ToCV is transmitted by B. tabaci, Trialeurodes abutiloneus and T. vaporariorum while TICV is transmitted only by T. vaporariorum), and they induce similar symptoms on tomato plants, a sensitive and specific diagnosis method is desirable. In addition, a rapid discriminating method of the vectors is essential for monitoring and control activities and epidemiological studies. For these reasons, a combined protocol based on one-step multiplex real-time reverse transcription (RT)-PCR has been developed for the identification of T. vaporariorum, two invasive species of the complex B. tabaci (MEAM1 and MED) and for the specific detection of ToCV and TICV in whiteflies and plants

Molecular Diagnosis of Chrysanthemum stunt viroid for Routine Indexing

In 2002, a two-year study was started to check for Chrysanthemum stunt viroid (CSVd) during the production and selective breeding of new chrysanthemum varieties in a central-Italy flower-growing farm. Two molecular techniques, one-tube RT-PCR and tissue printing for hybridization assays, were improved for their effectiveness in viroid detection at different stages of plant selection. Both molecular techniques proved sensitive, reliable and easy to apply in a programme of routine indexing for the production of new and healthy chrysanthemum varieties

In vitro thermotherapy and shoot-tip culture to eliminate Caper latent virus in Capparis spinosa

Capparis spinosa plants in the Sicilian Islands, Italy, are frequently infected with Caper latent virus (CapLV). CapLV affects the vigour and longevity of caper plants and exacerbates the effect of other adverse biotic and abiotic factors. To have CapLV-free cuttings of caper for multiplication and new planting is therefore advantageous for a revival of this crop wherever it is cultivated. An improved procedure for the in vitro thermotherapy combined with the culture of the shoot tips of C. spinosa has been applied to caper material collected from Salina (Aeolian Archipelago) and Pantelleria. More than of 60% (Salina) and 90% (Pantelleria) of the shoot tips survived, and 89–93% of the regenerated plantlets were CapLV-free when tested by RT-PCR. This is the first report on eliminating CapLV from caper plants