For my Ph.D (Microbial biofilms), i am going to use Azotobacter (Gram negative, N fixing bacteria) strain. I have to study the colonisation behavior of this bacteria in wheat rhizosphere. For this purpose, if i could tag GFP in Azotobacter, it will be easy to visualize and quantify the root colonisation. Is there any source for supply of GFP plasmid free of cost for academic purpose