Tomato stands firm in face of fungus

Scientists at the University of Amsterdam have discovered how to keep
one's tomatoes from wilting - the answer lies at the molecular level.
The story of how the plant beat the pathogen, and what it means for
combating other plant diseases has just been published.
Farmers and fellow agriculturalists are continuously battling the
ability of plant pathogens to co-evolve alongside their host's immune
system. In agriculture, the most environmentally friendly way to combat
the evolutionary change in plant diseases is to make use of the innate
immune system of plants. Growers can cross into targeted plant varieties
certain polymorphic resistance genes that occur in related plants,
thereby naturally boosting the plant's immune system.

In this study, Dr. Martijn Rep and his team explored the molecular basis
of this previously established concept of crossing in resistance genes.
The authors considered the interaction between a fungal pathogen,
Fusarium oxysporum, and the tomato plant in which the fungus causes
Fusarium wilt disease.

The group found that a small protein secreted by some strains of the
fungus causes it to overcome two of the tomato's disease resistance
genes. However, a third resistance gene was shown to specifically target
this suppressor protein, rendering the plant fully immune to any fungal
strain that produces the protein. Thus, with the right set of resistance
genes, tomatoes can beat the fungus despite the latter's "molecular
tricks."

"This molecular analysis has revealed a hitherto unpredicted strategy
for durable disease control based on resistance gene combinations," say
the authors.