Archive for the ‘TYLCV’ Category

New tomato varieties in the fight against ToBRFV

The Italian company TomaTech is making great progress in the fight against ToBRFV. Starting next season, commercial varieties with intermediate resistance will be available. These include date tomatoes, midi plum and a number of colored varieties, both loose and on the vine.

This variety renewal starts with the date variety Dormaplum, which is described by TomaTech as the perfect tomato. It is very sweet, with a bright color and a uniform size, a weight of 16 grams and a Brix degree between 9 and 10. The balance between sweetness, acidity and structure is excellent.

The plant has an extraordinary high yield, suitable for long cycles and ideal for unheated greenhouses. TomaTech recommends grafting with two buds, and can be transplanted between the end of August and October.

The tomatoes have a long shelf life and are resistant to ToMV, Ff, TYLCV, ToBRFV. For those interested, seeds are available for trials.

Dormaplum, moreover, is a variety launched in southern Europe in 2020 which, despite numerous difficulties and limitations due to Covid-19, is proving to be an exceptional agronomic and commercial success.

For those who are instead looking for larger fruits, TomaTech offers cluster plums – still in the research phase – which seem very promising and are already available for long cycles with transplanting in August/October in Sicily and springtime in Lazio and Campania. Here too, free samples are available on request. To complete the current ToBRFV resistant/tolerant variety range there are three coloured specialities: ‘Tomelody’, ‘Cantando’ and ‘Tiny Tom Orange’.

Tomelody stands out for its sweetness, a tasty lemon-colored date variety with a distinctive shape and rich flavor. Perfect as a snack, light and healthy. High yield with more than 25 fruits per cluster of 15-17 grams each. The plant is resistant to Fol:0, ToMV, ToBRFV and is extremely versatile and suitable for all seasons.

Cantando is an orange date tomato with a high palatability, a Brix value between 8 and 10 and a smooth texture. The plant is very generative, well balanced with short internodes and resistant against Vd, Fol:0.1, ToMV, Mj, ToBRFV. The variety is suitable for transplanting between September and October.

Tiny Tom Orange is a sweet, fruity and aromatic orange date tomato. They weigh only 12 grams and have a Brix value ranging from 9 to 10. The variety is resistant to Vd, Fol:0.1, ToMV, Mj and ToBRFV.

 “At TomaTech, we are aware that the fight against ToBRFV is far from over, but we are confident in the work done. We are now able to launch these promising varieties and more will follow. So far, we have a valuable tool to contain this disease,” said the TomaTech research team.

For more information:
+39 351 7614 587

Publication date: Wed 17 Mar 2021
© HortiDaily.com

Read Full Post »

Read Full Post »


Aug 22,2014



A team of virologists and plant geneticists at Wageningen UR has demonstrated that when tomato plants contain Ty-1 resistance to the important Tomato yellow leaf curl virus (TYLCV), parts of the virus DNA (the genome) become hyper-methylated, the result being that virus replication and transcription is inhibited. The team has also shown that this resistance has its Achilles heel: if a plant is simultaneously infected with another important (RNA) virus, the Cucumber mosaic virus (CMV), the resistance mechanism is compromised.

Antiviral defence via RNAi
Plant defence to viruses usually depends on RNA interference (RNAi). The genetic material of many viruses consists of RNA. A complex process in the plant causes the virus RNA to be chopped up into pieces, which means the virus can no longer multiply. In contrast to most other disease-causing plant viruses, the genetic material in TYLCV is DNA, not RNA. Therefore antiviral RNAi defence to these viruses has to happen somewhat different.

TYLCV is one of the most economically important plant viruses in the world; for this virus a number of resistance genes (Ty-1 to Ty-6) are available to commercial plant breeders. In 2013 the researchers in Wageningen succeeded in identifying and cloning the Ty-1 gene, which happened to present a member from an important class of RNAi-pathway genes. This led to a publication in PLoS Genetics. Their recent publication in the journal PNAS shows that although Ty-1 resistance depends on RNAi, instead of the genetic material being chopped up, it is being ‘blocked’ by methylation of the virus DNA.

No cross protection
A well-known phenomenon in the plant world is the ‘immunisation’ of plants by infecting them with relatively harmless viruses. The latter ensures that the defence mechanisms in plants are activated and provide ‘cross protection’ against more harmful, related viruses.

To their great surprise, the Wageningen researchers discovered that infection with CMV, a virus that contains RNA as genetic material and that, as a result, is not affected by the Ty-1 resistance mechanism, actually compromised resistance to the TYLCV virus. According to the researchers, this is a warning to plant breeders. The use of the Ty-1 gene does provide resistance, but the mechanism will be at risk in plants grown in greenhouses and fields if the plants are attacked by various other types of viruses.

Explore further: Virus rounds up enzymes, disarms plant
More information: Patrick Butterbach, Maarten G. Verlaan, Annette Dullemans, Dick Lohuis, Richard G. F. Visser, Yuling Bai, and Richard Kormelink. “Tomato yellow leaf curl virus resistance by Ty-1 involves increased cytosine methylation of viral genomes and is compromised by cucumber mosaic virus infection.” PNAS 2014 ; published ahead of print August 18, 2014, DOI: 10.1073/pnas.1400894111
Journal reference: PLoS Genetics Proceedings of the National Academy of Sciences
Provided by Wageningen University

Read more at: http://phys.org/news/2014-08-virus-dna.html#jCp

Read Full Post »