PHYTO MEDIZIN Mitteilungen der Deutschen ... - Die DPG

BV1 and BC1 can complement for mechanical transmission in inoculated
leaves, but in systemically infected leaves fail to support viral invasion of
non-phloem cells. Since in mixed infections with CMV, AbMV has been
shown to escape from the phloem, some other (perhaps gene silencing-)
mechanism may be responsible for AbMV tissue limitation.
Future challenges in the innovation of detection and identification techniques
in plant virology
N Klijn and JW Roenhorst; Plant Protection Service, Wageningen
Since the end of the eighties the strategy of the Dutch government focussed
on the reduction of the use of pesticides. As a result less capacity and budget
was available for research in the field of plant health. This led to a dramatic
loss of expertise, especially in the field of virology. A similar tendency could
be observed internationally. Since healthy seeds and planting material are of
crucial importance to manage virus diseases, this loss eventually will result in
increasing problems caused by viruses. The consequences of the lack of diagnostic
methods for potentially harmful viruses and the loss of knowledge
and expertise to develop such methods, has to be brought into attention of the
responsible decision makers. Therefore coherent research proposals have to
be drafted and submitted to national and international governments and organisations.
It should be stressed that is necessary to maintain both knowledge
and practical expertise in the field of plant virology. New detection and
identification methods have to be developed based on reference collection
material that, in combination with the classical methods, enable to study the
biological and epidemiological aspects of viruses. Such approach will provide
a solid base, which is essential to manage actual and future virus problems
by prevention and control.
The allelic resistance genes Tm-2 and Tm-22 against Tomato mosaic virus
differ only in 4 amino acids but recognize two independent domains of
the ToMV MP
A Gerhardts, M Strasser, M Silber und AJP Pfitzner; Institute of Genetics, Department
of General Virology, University of Hohenheim, Stuttgart
Transposon insertion experiments in tomato plants led to the isolation of the
Tm-2 resistance gene against ToMV.. Sequence analysis revealed that Tm-2
codes for a 861 aa protein which belongs to the CC-NBS-LRR type of resistance
genes. Surprisingly, Tm-2 contains only 4 amino acid exchanges located
in two different domains of the protein in comparison to the allelic Tm-
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