Further study on the potential of Frateuria defendens as a biocontrol agent against phytoplasmas

Frateuria defendens isolated from the gut of phytoplasma insect vector is being studied as a possible bio-control agent to control yellows disease. Its low survival as endophyte in the plant tissue suggests exploiting its secreted antibacterial metabolites. Different isolates of F. defendenswere tested for their inhibitory activity. The best isolate was introduced to melon plants and its cells were found in the plant sap 5 and 10 days post application. Sap, obtained from F. defendens- treated plants, inhibited the growth of Spiroplasma melliferum(a model mollicute) and altered the endophytic community of the plants. The results point at F. defendens as a candidate to develop bio-control measures against the yellows disease.