Direct identification, and localization of Azospirillum in the rhizosphere of wheat using fluorescence-labelled monoclonal antibodies and confocal scanning laser microscopy

Summary Azospirillum is a soil bacterium with plant growth-promoting potential. Strain-specific monoclonal antibodies (mAbs) which bind to different antigenic determinants of the bacterial cell surface with high specificity for A. brasilense Sp7 were used to monitor this bacterium in the rhizosphere of wheat plants. The mAbs were marked directly with the fluorochromes fluorescein (FITC) or tetramethylrhodamine (TRITC). With the labelled mAbs and confocal scanning laser microscopy, an in situ identification and localization of this bacterium in root segments was possible.