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Chayote (Sechium edule (Jacq.) Sw.) is a vigorous perennial and climbing cucurbits, native to Mesoamerica, and cultivated for alimentary purposes in the American continent, Australia, New Zealand, South Europe, Asia and Africa. During spring 2019, some chayote plants showing bright yellow vein banding rings and lines were observed in a private garden in South Italy (Campania region). Symptoms coalesced in some leaves, covering almost the whole foliar area. Double-stranded RNAs were extracted from symptomatic leaves of a single chayote plant and reverse-transcribed, randomly amplified, and submitted to Illumina sequencing (Marais et al., 2018). Reads were assembled using CLC Genomics Workbench 11.1 (http://www.clcbio.com). Contigs were then annotated by Blastn and Blastx comparison with the Genbank database, which allowed the identification of eight contigs of between 380 and 980 nucleotides sharing significant identity with alfalfa mosaic virus (AMV) genomic RNAs. No other viral contigs were identified. Mapping of reads on AMV genomic RNAs identified 4,209 AMV reads (1.26% of total reads) and allowed the scaffolding of the contigs into three scaffolds corresponding to the three AMV genomic RNAs. To complete the sequence of the AMV chayote isolate genome (named See-1), primers were designed from the contig sequences and used to amplify RACE PCR products spanning the 5' and 3' terminal regions of the three genomic RNAs using the SMARTer™ RACE cDNA Amplification Kit (Clontech, China). All amplicons were cloned into the pGEM-T vector (Promega, USA) and sequenced (three clones for each amplicon) by Microsynth Seqlab (Microsynth AG, Switzerland). Finally, the complete genomic sequences of the three RNAs were assembled by MacVector 17.5 (MacVector Inc., USA). The RNA1, RNA2 and RNA3 of See-1 are 3,643, 2,593 and 2,037 nt respectively (GenBank accession Nos. MT093209 to MT093211), and share the highest nt sequence identity with the RNA1 and RNA3 of AMV isolate (HZ) from tobacco (99.5% for RNA1, HQ316635; 98.7% for RNA3, HQ316637) and with the RNA2 of isolate AMV-Gym from Gynostemma pentaphyllum (98.1%, MH332898), both from China. AMV isolate See-1 was classified as belonging to subgroup I based on the presence of a BamH I and two AvaII sites in the CP ORF (Parrella et al., 2000). Reverse transcription polymerase chain reaction, using primers targeting the CP gene (Parrella et al., 2000), confirmed AMV infection in three symptomatic cayote plants including that used for Illumina sequencing, with 100% of nt sequence identity of amplicons. Three plants each of Chenopodium amaranticolor, Nicotiana benthamiana and Solanum lycopersicon were mechanically inoculated with sap from isolate See-1 infected plant, leading to the appearance of typical AMV symptoms in all three hosts ten days post-inoculation (Jaspars & Bos, 1980). This note describes the first detection of AMV in cayote in Italy and, to the best of our knowledge, in the world. In some areas of Southern Italy, climatic conditions are favorable enough to allow chayote development in the wild. Further studies would be desirable to determine the distribution and incidence of AMV in chayote and to understand the possibility that this species may play a role in AMV epidemiology, representing a threat to other susceptible crops.

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.

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During spring-summer 2012, 2013, and 2015, 10 samples of bell pepper (Capsicum annuum) plants showing basal bright rings and mosaic of the leaves with some necrotic patches, necrotic stems, and fruits with brown patches and corky rings, were identified in the Campania region (southern Italy), in a family garden (four plants in 2012 and three plants in 2015 of the Friariello ecotype) and in a commercial greenhouse (two plants of the Papaccella ecotype in 2012 and one plant of the Eppo hybrid in 2013). Symptomatic samples were tested at the Institute for Sustainable Plant Protection in Portici (Napoli, Italy). Screening of leaf and fruit symptomatic tissues by double antibody sandwich (DAS)-ELISA with commercial kits of antisera (Bioreba AG, Switzerland) to Cucumber mosaic virus(CMV), Alfalfa mosaic virus (AMV), Tomato spotted wilt virus (TSWV), Tomato mosaic virus(ToMV), Pepper mild mottle virus (PMMoV), and by indirect plate trapped antigen (PTA)-ELISA against potyviruses (potygroup test), gave negative results, whereas all samples tested positive in antigen-coated-plate (ACP)-ELISA with antisera, kindly provided by Dr. P. Roggero (Plant Virology Institute, Torino, Italy), produced against a tomato isolate (namely TI1 isolate) of Parietaria mottle virus (PMoV). The results from indirect ELISA were subsequently confirmed with reverse transcription (RT)-PCR using PMoV specific primers designed to amplify the entire gene of the movement protein (MP): PMoVMP1a (5?-AGGGTTTGAAATGGCATTTGTTC-3?) and PMoVMP2b (5?-CTTAGTGGACATTCACGAATATC-3?). A healthy pepper plant was used as a negative control both in ELISA and RT-PCR assays. RT-PCR products of 916 bp, which covered approximately 40.4% of PMoV RNA3 (isolate T32 as reference, accession number KT005245), were obtained in all symptomatic samples and one amplicon for each pepper ecotype and year of sampling was cloned and sequenced. The nucleotide sequences of the MP gene of three Italian PMoV isolates were deposited in GenBank under accession numbers LT160068 (isolate Fri-1, from the Friariello ecotype, in 2012), LT160069 (isolate Pap-1, from the Papaccella ecotype, in 2012), and LT160070 (isolate Fri-2, from the Friariello ecotype, in 2015). Isolates Fri-1 and Pap-1 showed 98.4 and 97.6% identity with the Spanish PMoV isolate JBT1 from tomato (accession number AM182747), respectively, while Fri-2 showed 96.7% identity with the Spanish PMoV isolate AC1 from tomato (accession number AM182743). To our knowledge, this is the first report of PMoV infecting bell pepper in Italy. In 2004, PMoV was identified in pepper crops in Spain (Janssen et al. 2005). The virus is also known to infect economically important plants as tomato in Italy, France, Spain, and Greece (Aramburu 2001;Marchoux et al. 1999; Roggero et al. 2000), as well as the ornamental Mirabilis jalapa (Parrella 2002). This new finding of PMoV in pepper in Italy confirms the tendency of the virus to broaden its range of natural hosts, particularly concerning species of economic interest. The symptoms induced by PMoV on pepper can be visually confused with those caused by other viruses infecting pepper (e.g., TSWV, CMV). Therefore, it is necessary to monitor regularly for the presence of PMoV in pepper crops in order to know the real incidence of the disease in the field with the aim of developing efficient and durable disease control strategies.