image analysis method for determination of spatial colonization patterns of bacteria in plant rhizosphere

• Published in: Applied microbiology and biotechnology 1999-05, Vol.51 (5), p.653-658
• Main Authors: Roberts, D.P, Kobayashi, D.Y, Dery, P.D, Short, N.M. Jr
• Format: Article
• Language: English
• Subjects: Bacteria; Biological and medical sciences; Biology of microorganisms of confirmed or potential industrial interest; Bioluminescence; Biotechnology; Colonization; Cucumis sativus; Enterobacter cloacae; Fundamental and applied biological sciences. Psychology; Miscellaneous; Mission oriented research; rapid methods; Rhizosphere; Roots; Seeds; spatial distribution; Vegetables
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s002530051446

A method that allows the rapid visualization of bacterial spatial colonization patterns on roots for the determination of general colonization trends was developed. This method, which analyzes images of roots, and bioluminescence-enhanced images of bacterial colonization patterns on these roots, was used to study the colonization patterns of seed-applied Enterobacter cloacae strain E6 on 3-day-old cucumber plants. Conventional dilution-plating methods indicated that E6 colonized cucumber tap roots in high populations and that these populations significantly decreased as the distance from the seed increased. In addition to confirming these observations, image analysis indicated that colonization by E6 significantly decreased on lateral roots as the distance increased horizontally away from the tap root, and that this bacterium did not evenly cover the most densely colonized regions of the cucumber root system. Results from these experiments indicate that the majority of E6 populations on cucumber roots after seed application are limited to the upper regions of the tap root and that E6 does not effectively colonize other regions of the root system.