Chemotaxis of deleterious rhizobacteria to velvetleaf (Abutilon theophrasti Medik.) seeds and seedlings |
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Authors: | MFT Begonia RJ Kremer |
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Institution: | Department of Agronomy, and Cropping Systems and Water Quality Research Unit, Agricultural Research Service, U.S. Department of Agriculture, University of Missouri, 144 Mumford Hall, Columbia, Missouri 65211, USA |
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Abstract: | Abstract Intact seeds and seed and seedling root exudates of velvetleaf ( Abutilon theophrasti Medik.) were used as chemoattractants in experiments to determine the relative importance of chemotaxis in spermosphere and rhizosphere colonization by selected rhizobacteria. Results for soft-agar, capillary tube and soil chemotaxis assays indicated that selected deleterious rhizobacteria were specifically attracted to seed and seedling root exudates. Several amino acids and sugars detected in exudates were chemoattractants for these rhizobacteria. Using soil-chemotaxis assemblies, migration of rhizobacterial isolates through 2-cm distances of soil toward velvetleaf seeds or exudates was detected within 24 h. Isolates were not detected at the same site in soils without seeds or exudates until 72 h after inoculation. These results suggest that attraction of delecterious rhizobacteria toward seeds and seedling roots mediated by exudates (chemotaxis) might be the first step in establishment and subsequent colonization of biological control bacteria on weed seeds and seedling roots in soil. |
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Keywords: | Deleterious rhizobacteria Chemotaxis Spermosphere Rhizosphere Weed seeds and seedlings Abutilon theophrasti Medik |
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