Immunofluorescence colony-staining (IFC) as a concept for bacterial detection in quality testing of plant materials and ecological research

Immunofluorescence colony-staining (IFC), as a concept in bacterial detection, has developed during the past decade, providing several new options for the study of culturable plant-associated bacteria: (1) in situ detection of target colony-forming units on or in plant parts, such as on roots or in stem sections; (2) selective isolation of cross-reacting bacteria for research on the improvement of the reliability of serological detection systems; (3) distinction between culturable and non-culturable cells; (4) simultaneous detection of different target bacteria using different fluorescent markers and a dual fluorochrome-filter system. IFC-positive colonies can be directly identified by isolation or PCR, which makes it easier to recognize false positive results. The use of IFC for the selective isolation of cross-reacting bacteria forms a major tool for the further improvement of the specificity of IFC and serological assays.