At this moment we are testing the Serratia plymuthica bacteria on cauliflower and oilseed rape seedlings for their biocontrol and plant growth promoting qualities.
In the BIOCOMES project we are developing a biological control agent against Verticillium wilt on Brassica. Actually no control against Verticillium wilt exists, and there is no other possibility to suppress the pathogen. We are using two biological control agents Serratia plymuthica and Paenibacillus polymyxa to develop a method for seed treatment against Verticillium wilt.
Picture 1 and 2 are microscopic photographs of the root tissues of a 2-week old cauliflower (the picture on the top) and oilseed rape seedlings (the picture on the bottom) that were made using Confocal Laser Scanning Microscopy, a technique that enables obtaining high resolution images in 3-D by taking images at different depths of a specimen. The seeds of the plants were previously primed with bacteria from the Serratia genus labelled with the Green Fluorescent Protein (GFP). This protein shows a bright green fluorescence when exposed to light in the blue to ultraviolet range. The bacteria colonizing the roots are visible as green dots on the (red) root tissue.
The last picture shows the same plants photographed under UV light. The areas of the seedlings that glow green are colonized by the beneficial bacteria at most.