Paris, France
February 2010
Fusarium oxysporum is a very common fungus found in soils throughout the world, some strains of which are pathogenic. The only method available at present to control these strains is the use of methyl bromide. INRA scientists in Dijon have developed a biological method to control pathogenic strains of Fusarium oxysporum by clarifying the conditions for the introduction in soil of a strain known for its lack of pathogenicity.
Fusarium oxysporum is a common fungus that is found in soils throughout the world. Some of its numerous strains are pathogenic, while others are non-pathogenic and can protect plants against infection by a pathogenic strain. This protection phenomenon has been known for many years, and scientists have now isolated a strain called Fo47 which provides particularly efficient protection. The protective mechanisms of this strain have been widely studied, and its efficacy renders it a good candidate for the development of a biological agent to control pathogenic strains. The only traditional method available until now to eliminate pathogenic populations was to use methyl bromide, but this chemical also destroyed all soil microflora and has now been banned.
Researchers in Dijon have studied how strain Fo47 could be introduced directly into the soil, and in particular examined the conditions for its persistence; although this method is effective, the strain needs to remain active in the soil for a sustained period of time. In addition, the scientists also focused on the effects of Fo47 on soil microflora. Indeed, the strain must be effective to protect the plant, but must not modify the composition of soil microflora.
From an experimental point of view, the problem of this research resided in the fact that no system was available to measure the impact of a biological agent on all soil microflora. The development in recent years of soil DNA extraction and molecular typing techniques to characterise soil flora (bacterial and fungal) has enabled scientists to carry out studies in two types of soil with markedly differing physicochemical conditions.
The results showed that Fo47 was capable of developing in different types of soil, and its introduction had very little impact on the microbiological equilibrium of the soil measured after one year. These findings mean that Fo47 is a good candidate for the development of a biological agent to control pathogenic strains of Fusarium oxysporum.
Scientific contact:
Véronique Edel-Hermann
UMR1229 Joint Research Unit for Soil Microbiology and the Environment MSE
INRA/Université de Bourgogne
17 rue Sully - BP 86510
21065 Dijon Cedex France
Veronique.Edel@dijon.inra.fr
Tel. + 33 (0) 3 80 69 34 50
Fax + 33 (0) 3 80 69 32 24
Website http://www2.dijon.inra.fr/umrmse/
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