Scientists of Plant Research International of Wageningen UR have
identified the virus that causes great damage in tomato cultivation in
Mexico where the disease is known as 'Marchitez', which means withered. The
name of the new virus is tomato marchitez virus.
The virus was found to be related to the tomato torrado virus, earlier
discovered by Wageningen UR. The scientists recently published their
findings in Archives of Virology. Identification of the virus now makes it
possible for breeding companies to develop cultivars with resistance against
the virus.

Tomato marchitez virus is found to be closely related to the earlier
discovered tomato torrado virus, which in for instance Spain, causes the
damaging 'Torrado' disease in tomato. Both viruses are now classified into
the new plant virus genus Torradovirus. Tomato marchitez virus causes leaf
necrosis and serious damage to the fruits, resulting in a strong yield
reduction. Whitefly is one of the vectors of the virus.

The intensive cooperation of Plant Research International and De
Ruiter Seeds, vegetable seed company in Bergschenhoek, resulted in rapidly
gaining insight into the causal agents of two important tomato diseases.

The Plant Virology Group of Plant Research International investigated
samples of tomato plants, originating from commercial farms in Mexico and
Spain, which showed clear symptoms. Virus particles that had not been
described before were found in these samples. The viruses were then fully
characterized and described as new species.

It could be proven for both species that they were the causal agents
of the disease symptoms found in Mexico and Spain. The research was financed
by De Ruiter Seeds, the company which has meanwhile placed cultivars on the
market with resistance against both viruses.

Full RNA sequences have been determined of tomato marchitez virus as
well as tomato torrado virus and these have recently been published in
Archives of Virology. It is remarkable that in a short period of time two
new viruses have been found and described that can on the basis of their
unique characteristics be ascribed to a new plant virus genus.


Publication: M. Verbeek, A.M. Dullemans, J.F.J.M. van den Heuvel, P.C.
Maris, R.A.A. van der Vlugt, Tomato marchitez virus, a new plant
picorna-like virus from tomato related to tomato torrado virus. Archives of
Virology, published online 29 October 2007).

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