An outbreak of a new disease infecting tomatoes occurred in October-November 2014 at the Ohad village in Southern Israel. Symptomatic plants showed a mosaic pattern on leaves accompanied occasionally by narrowing of leaves and yellow spotted fruit. The disease spread mechanically and rapidly reminiscent of tobamovirus infection. Epidemiological studies showed the spread of the disease in various growing areas, in the South and towards the Southeast and Northern parts of the country within a year. Transmission electron microscope (TEM) analysis showed a single rod-like form characteristic to the Tobamovirus genus. We confirmed Koch’s postulates for the disease followed by partial host range determination and revealed that tomato cultivars certified to harbor the Tm-22 resistance gene are susceptible to the new viral disease. We further characterized the viral source of the disease using a range of antisera for serological detection and analyzed various virus genera and families for cross-reactivity with the virus. In addition, next generation sequencing of total small RNA was performed on two cultivars grown in two different locations. In samples collected from commercial cultivars across Israel, we found a single virus that caused the disease. The complete genome sequence of the new Israeli tobamovirus showed high sequence identity to the Jordanian isolate of tomato brown rugose fruit virus.

Cucumber green mottle mosaic virus (CGMMV) was first described in 1935 infecting cucumber, making it one of the first plant viruses to be studied. Its initial distribution occurred out of England to other countries. This was followed by its distribution from England and these other countries to additional countries. This process increased slowly between 1935 and 1985, faster between 1986 and 2006, and rapidly between 2007 and 2016. The discovery that it diminished cucurbit fruit yields and quality, especially of watermelon, prompted a substantial research effort in worst-affected countries. These efforts included obtaining insight into its particle and genome characteristics, evolution, and epidemiology. CGMMV's particle stability, ease of contact transmission, and seed transmissibility, which are typical tobamovirus characteristics, explained its complex disease cycle and its ability to spread locally or over long distances without a vector. Knowledge of its disease etiology and epidemiology enabled development of integrated disease management approaches that rely heavily on diverse phytosanitary measures. Dispersal of seed-borne infection through the international seed trade following cucurbit seed crop production in tropical or subtropical countries explains its recent rapid dispersion worldwide.

Abstracti mb_951 87..96Aphids respond to environmental changes by developing alternative phenotypes with differing reproductive modes. Parthenogenetic reproduction occurs in spring and summer, whereas decreasing day lengths in autumn provoke the production of sexual forms. Changing environmental signals are relayed by brain neuroendocrine signals to the ovarioles. We combined bioinformatic analyses with brain peptidomics and cDNA analyses to establish a catalogue of pea aphid neuropeptides and neurohormones. 42 genes encoding neuropeptides and neurohormones were identified, of which several were supported by expressed sequence tags and/or peptide mass analyses. Interesting features of the pea aphid peptidome are the absence of genes coding for corazonin, vasopressin and sulfakinin and the presence of 10 different genes coding insulin related peptides, one of which appears to be very abundantly expressed.

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Global seed trade contributed to development and improvement of world agriculture. An adverse effect of global seed trade is reflected in disease outbreaks in new growing areas, countries, and continents. Among the seed-borne viruses, Tobamovirus species are currently considered a peril for crop production around the world. The unique tobamoviral particles confer stability to the RNA genome and preserve their infectivity for years. High titer of Tobamovirus species accumulates in reproductive organs leading to viral particles adsorbed to seed coat, which potentially establish a primary infectious source. Tobamovirus-contaminated seeds show very low virus transmission in grow-out experiments as detected by enzyme-linked immunosorbent assay (ELISA) and reverse transcription polymerase chain reaction (RT-PCR) analysis. Interestingly, in situ immunofluorescence analysis of Cucumber green mottle mosaic virus (CGMMV) reveals that the perisperm-endosperm envelope (PEE) is contaminated as well by the Tobamovirus. Indeed, chemical seed disinfection treatments that affect primarily the seed coat surface are efficient for several Tobamovirus species but apparently do not prevent seed transmission of CGMMV to occur. Tobamovirus infection of the seed internal layers, which rarely includes the embryo, may partially follow the direct invasion pathway of Potyviruses such as Pea seed-borne mosaic virus (PSbMV) to pea embryo.