It deals with pathogens that effects the plants, plant-bacteria interactions, biofertilizers. Some bacteria fix nitrogen to the root nodules. Agrobacterium tumefaciens is used as a natural genetic tool to insert the plasmid. Phyto bacteriology focuses mainly on taxonomy and pathogenicity factors. Recent research on phytobacteriology includes the antagonistic activity of microorganism against bacterial infections, intracellular bacteria liberobacter, nucleation of bacteria in the active bundles of plants, nonparasitic rhizobacterium.