Tomato Brown Rugose Fruit Virus: Seed Transmission Rate and Efficacy of Different Seed Disinfection Treatments

Abstract

Tomato brown rugose fruit virus (ToBRFV) is a highly infectious virus, that is becoming a threat to tomato production worldwide. In this work we evaluated the localization of ToBRFV particles in tomato seeds, its seed transmission rate and efficacy of disinfection, and the effects of different thermal- and chemical-based treatments on ToBRFV-infected seeds’ germination. Analyses demonstrated that ToBRFV was located in the seed coat, sometime in the endosperm, but never in the embryo; its transmission from infected seeds to plantlets occurs by micro-lesions during the germination. The ToBRFV seed transmission rate was 2.8% in cotyledons and 1.8% in the third true leaf. Regarding the different disinfection treatments, they returned 100% of germination at 14 days post-treatment (dpt), except for the treatment with 2% hydrochloric acid +1.5% sodium hypochlorite for 24 h, for which no seed germinated after 14 dpt. All treatments have the ability to inactivate ToBRFV, but in six out of seven treatments ToBRFV was still detectable by RT-qPCR. These results raise many questions about the correct way to carry out diagnosis at customs. To our knowledge, this is the first study on the effective localization of ToBRFV particles in seeds.

Global Plant Virus Disease Pandemics and Epidemics

“…Since then, it has been found elsewhere in the Middle East (Israel, Turkey), and in European countries (Germany, Greece, Cyprus, Czech Republic, France, Italy, Poland, Spain, the Netherlands, UK), East Asia (China), North America (Mexico, USA), South America (Chile) and North Africa (Egypt, Sudan). In these countries, it is currently causing a serious virus disease epidemic, particularly in tomato crops grown under protected cropping [ 121 , 122 , 123 , 124 ]. It differs from the tomato infecting tobamoviruses tomato mosaic virus (ToMV) and tobacco mosaic virus (TMV) in being able to infect tomato plants carrying virus resistance gene Tm-2 2 , so all TMV- and ToMV-resistant tomato cultivars become ToBRFV infected [ 208 ].…”

“…These properties enable its efficient contact transmission when a healthy tomato plant comes into contact with an infected plant, contaminated soil, contaminated nutrient solutions or a contaminated surface, such as equipment, tools, hands and clothing used during pruning or trellising within protected cropping situations. It is also transmitted by grafting, cuttings [ 122 , 123 , 124 ] and bumblebee pollinators [ 211 ]. As with TMV and ToMV, it is seed-borne at low levels when tomato seeds become surface contaminated with its virions.…”

“…As with TMV and ToMV, it is seed-borne at low levels when tomato seeds become surface contaminated with its virions. Seed transmission results from contact between virion-contaminated seeds coats and young seedlings [ 123 ]. Trade in contaminated tomato seeds, combined with trade in infected seedlings and fruits, inadvertently results in its distribution within countries, to neighboring countries and, especially with contaminated seeds, over much greater distances internationally [ 124 ].…”

“…Potential alternative ToBRFV hosts identified by sap inoculation include eggplant ( Solanum melongena ), petunia ( Petunia hybrida ) and the weed S. nigrum [ 208 ]. Its epidemiology is incompletely understood but is being investigated currently [ 123 ].…”

Tomato brown rugose fruit virus: A new threat for tomato and pepper production

“…Osim lakog mehaničkog prenošenja, kao i drugi virusi iz roda Tobamovirus, i ToBRFV se prenosi semenom (Dombrovsky and Smith, 2017). Ispitujući prenošenje ToBR-FV semenom paradajza, Davino et al (2020) su utvrdili da je virus lokalizovan u semenjači, retko je prisutan u endospermu i nikada u embrionu. Do prenosa virusa sa semena i zaražavanja biljaka dolazi kroz mikropovrede koje nastaju prilikom klijanja i nicanja biljaka.…”