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Bradyrhizobium Japonicum And Soybean Symbiotic Response To Glyphosate In Glyphosate-Tolerant Soybeans, Jodie M. Scheele, C. Andy King, Marilynn K. Davies, Larry C. Purcell

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Soybean (Glycine max) grain contains approximately 40% protein and 6.5% nitrogen (N) on an elemental basis. Therefore, the plant requires an abundant N supply throughout its life cycle, and symbiotic N fixation of soybean with Bradyrhizobium japonicum provides 40 to 85% of the soybean N. Although soybean cultivars have been genetically engineered to withstand the herbicide glyphosate, B. japonicum grown in culture is sensitive to glyphosate. We hypothesized that glyphosate applied to glyphosate-tolerant soybean would inhibit nodulation by B. japonicum unless B. japonicum could also be selected for glyphosate tolerance. Cultures of B. japonicum were challenged with sublethal doses of …