Tomato Breeder IDs Gene That Provides Resistance to Devastating Disease
October 8, 2020 
Enza Zaden, one of the world’s leading vegetable breeders, has found a potential solution for tomato growers to beat the devastating tomato brown rugose fruit virus (ToBRFV). The company’s tomato breeding team has identified the gene that provides high resistance to the worldwide rapidly spreading virus.
Sergio de la Fuente van Bentem, Plant Pathology Researcher at Enza Zaden, says the company has been working for years to find a solution.
“Now that we have discovered an answer, we will keep on working hard to develop tomato varieties that are highly ToBRFV resistant,” says van Bentem. “We expect to have these ready in the coming years.”
Enza Zaden researchers believe the gene is like no other currently known in the field, and offers high resistance to ToBRFV, also called tobamo after its genus.
With this innovation, the introduction of ToBRFV resistance could potentially secure long-term production for the tomato industry.
Since it was first discovered in Israel in 2014, ToBRFV has spread to parts of Europe, North America, Asia, and Africa. Its easy spread via mechanical transmission makes it a fast mover.
ToBRFV has an incubation period of two to three weeks before symptoms occur, making it an uphill battle to contain a localized spread once it begins.
With an intermediate resistance (IR) level, the virus propagation is delayed but can still enter tomato plants, which will eventually show symptoms.
The tomato plants tested at Enza Zaden research stations did not show any ToBRFV symptoms. Van Bentem says even growers in regions currently free of ToBRFV will likely be paying attention to this innovation as the virus has already spread faster than anticipated.
Enza Zaden will protect the identification of the gene providing high resistance and the tomato varieties they will create with relevant intellectual property rights.
Kees Könst, Enza Zaden’s Crop Research Director for Tomato, says when the team at Enza Zaden first heard about ToBRFV from its sales representatives in the Middle East in 2014, their knowledge of other tobamo viruses such as tomato mosaic virus (ToMV) and tobacco mosaic virus (TMV) gave an indication of what was to come.
“We analyzed it and knowing it spreads mechanically, we realized it could easily travel all over the world,” he says.
De la Fuente van Bentem notes the industry already had a solution to ToMV and TMV: a single resistance gene that has been used for decades to stop these two viruses.
“This new tobamo virus is not hindered by that resistance, so the industry had to come up with a new solution,” he says.
Van Bentem says Enza Zaden’s approach was to screen for new resistance genes in its wild tomato germplasm – a huge seed collection of wild tomato relatives that are crossable with normal cultivated tomatoes.
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