First report of Tomato mottle mosaic virus in Solanum lycopersicum seeds in The Netherlands and intercepted in seed imported from Asia

Abstract

The seeds were imported from Asia and samples were screened in compliance with import testing requirements. A total of 3,000 seeds were tested for Tomato mottle mosaic virus (ToMMV; genus Tobamovirus) using the RT-PCR test (F-5476 and R-6287) from Levitzky et al. (2019). A product of the expected size (811 bp) was obtained in all subsamples (12 subsamples each of 250 seeds) and subsequently sent for Sanger sequencing. Sequences from four of these samples were compared against those in GenBank, and confirmed to be ToMMV (Accession Nos. OK334226, OK334230-32), with ≥99% nucleotide and 99-100% amino acid identity compared with the exemplar strain (KF477193; YP_008492931.1). To obtain the whole genome of the isolate, the 12 subsamples were bulked and sequenced by high throughput sequencing (HTS) as described by Fox et al. (2019) and bioinformatic analysis using the Angua pipeline (Fowkes et al., 2021). The whole genome of ToMMV was obtained (6375 bp; OK334224), and confirmed after a BLAST search (99.6% identity KF477193.1; Figure 1).The genome of Tomato mosaic virus (ToMV) was also found (OK334225).

Prevalences of Tobamovirus Contamination in Seed Lots of Tomato and Capsicum

“…Most prominent among these data are the observed high levels of incidence of ToBRFV and ToMMV in samples from very small lots of tomato seeds, significantly contributing to the observed overall contamination incidence of 25.3% in this sub-group. Noting that seed lots of this size are generally considered to represent propagules of plant breeding lines, there appears to be the possibility of significant levels of contamination of commercial germplasm with these viruses-an observation consistent with one previously made by Fowkes et al [14].…”

Identification of Tomato mottle mosaic virus in historic seed accessions originating from France, the Netherlands and Spain, indicates a wider presence before its first description

“…In summary, ToMMV was identified in seed accessions produced in different countries before its first description in 2013 (Li et al, 2013). ToMMV has already been reported from Spain (Ambrós et al, 2017) and the Netherlands (Fowkes et al, 2022) but to our knowledge this is the first report of ToMMV in seeds produced in France. The results of this study, together with the report on its presence in a sample misidentified as ToMV in the past (Nagai et al, 2018), indicate that ToMMV had already been present before its first description and is possibly more widespread than currently known.…”

A Reverse-Transcription Loop-Mediated Isothermal Amplification Technique to Detect Tomato Mottle Mosaic Virus, an Emerging Tobamovirus

“…ToMMV infection induces mosaic, mottle, narrowing, and crinkling symptoms on tomato plant leaves, as well as fruit necrosis [ 15 , 16 ], leading to stunted growth and reduced fruit yield. The virus was initially found in greenhouse-grown tomatoes in Mexico in 2013 [ 12 ], and subsequently detected in China [ 17 ], the USA [ 18 ], Israel [ 19 ], Spain [ 20 ], Brazil [ 21 ], Czechia [ 22 ], Mauritius [ 23 ], the Netherlands [ 24 ], and France [ 25 ]. Tomato ( Solanum lycopersicum L.) and pepper ( Capsicum annuum L.) [ 12 , 17 ] are the major hosts of ToMMV, and chickpea ( Cicer arietinum L.) [ 26 ], eggplant ( Solanum melongena L.) [ 27 ], and pea ( Pisum sativum L.) [ 28 ] have also been reported as natural hosts.…”