Root colonization of glyphosate-resistant soybeans by pathogenic
Fusarium fungi increased with glyphosate application.
Manipulated Organism:
Soybean (Glycine max).
Inserted Transgenes:
CP4 EPSPS gene cloned from Agrobacterium, which produces an
herbicide-resistant version of the enzyme targeted by the herbicide
glyphosate (Roundup).
Goal of This Study:
Previous research had demonstrated that when weeds are sprayed with
glyphosate, elevated levels of pathogenic Fusarium fungi are
associated with their roots. This study was designed to investigate
the phenomenon using glyphosate-resistant (GR) soybeans.
Results of This Study:
Fusarium colonization of the GR soybeans was twofold higher as a
result of the glyphosate treatment over a wide range of soil moisture
conditions.
Additional Comments:
"The combined effects of glyphosate with optimum to high soil moisture
that led to increased Fusarium populations (root colonization)
in this study may help explain the Fusarium disease epidemics
documented in GR soybean fields during wet growing seasons, notably in
1997" (p. 1718).
Source:
Means, N. E. and R. J. Kremer (2007). "Influence of Soil Moisture on Root
Colonization of Glyphosate-treated Soybean by Fusarium Species,"
Communications in Soil Science and Plant Analysis vol. 38, pp. 1713-20.
Author Affiliations:
University of Missouri, Columbia, Missouri; USDA Agricultural
Research Service, Columbia, Missouri.
Funding:
USDA and Ag Spectrum Company, Dewitt, Iowa.
Product Status:
GR soybeans have been grown commercially in the US since 1996 and
currently constitute over 90% of the US soybean crop.
Copyright 2009 The Nature
Institute.
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