Tomato Brown Rugose Fruit Virus Contributes to Enhanced Pepino Mosaic Virus Titers in Tomato Plants.

The tobamovirus tomato brown rugose fruit virus (ToBRFV), a major threat to tomato production worldwide, has recently been documented in mixed infections with the potexvirus pepino mosaic virus (PepMV) CH2 strain in traded tomatoes in Israel. A study of greenhouse tomato plants in Israel revealed severe new viral disease symptoms including open unripe fruits and yellow patched leaves. PepMV was only detected in mixed infections with ToBRFV in all 104 tested sites, using serological and molecular analyses. Six PepMV isolates were identified, all had predicted amino acids characteristic of CH2 mild strains excluding an isoleucine at amino acid position 995 of the replicase. High-throughput sequencing of viral RNA extracted from four selected symptomatic plants showed solely the ToBRFV and PepMV, with total aligned read ratios of 40.61% and 11.73%, respectively, indicating prevalence of the viruses. Analyses of interactions between the co-infecting viruses by sequential and mixed viral inoculations of tomato plants, at various temperatures, showed a prominent increase in PepMV titers in ToBRFV pre-inoculated plants and in mixed-infected plants at 18-25 °C, compared to PepMV-single inoculations, as analyzed by Western blot and quantitative RT-PCR tests. These results suggest that Israeli mild PepMV isolate infections, preceded by ToBRFV, could induce symptoms characteristic of PepMV aggressive strains.

Lettuce Chlorosis Virus Disease: A New Threat to Cannabis Production.

In a survey conducted in Cannabis sativa L. (cannabis) authorized farms in Israel, plants showed disease symptoms characteristic of nutrition deprivation. Interveinal chlorosis, brittleness, and occasional necrosis were observed in older leaves. Next generation sequencing analysis of RNA extracted from symptomatic leaves revealed the presence of lettuce chlorosis virus (LCV), a crinivirus that belongs to the Closteroviridae family. The complete viral genome sequence was obtained using RT-PCR and Rapid Amplification of cDNA Ends (RACE) PCR followed by Sanger sequencing. The two LCV RNA genome segments shared 85-99% nucleotide sequence identity with LCV isolates from GenBank database. The whitefly Bemisiatabaci Middle Eastern Asia Minor1 (MEAM1) biotype transmitted the disease from symptomatic cannabis plants to un-infected 'healthy' cannabis, Lactucasativa, and Catharanthusroseus plants. Shoots from symptomatic cannabis plants, used for plant propagation, constituted a primary inoculum of the disease. To the best of our knowledge, this is the first report of cannabis plant disease caused by LCV.