Some strains of Burkholderia gladioli are potential candidates for postharvest biocontrol of fungal rots in citrus and apple fruits

Three Burkholderia gladioli strains (DISTEF), recoveredfrom Strelitzia reginae, were biochemically and genomicallycharacterized and evaluated as potential candidatesfor post harvest biocontrol of fungal rots in citrusand apple fruits. Cell and cell-free culture filtratesinhibited in vitro, to a different extent, the growth ofRhodotorula pilimanae, Penicillium digitatum, Penicilliumexpansum, Botrytis cinerea, Aspergillus flavus, Aspergillusochraceus and Alternaria alternata. Conidialgermination was also inhibited in liquid culture assaysby bacterial cells, culture filtrates and concentrated culturefiltrates. All strains completely inhibited or significantlyreduced the incidence and severity of diseasescaused by P. digitatum and P. expansum to orange,lemon and apple fruits after 4 days incubation at 20°C.B. gladioli strain DISTEF-G completely inhibited P. digitatumand P. expansum growth after 9 days incubation.A partial control of green and blue mould was obtainedon citrus and apple wounds inoculated with culture filtrates.FAFLP analysis showed clear separation of DISTEFstrains of B. gladioli from type strains of B. gladioliand B. cepacia. The results suggest that B. gladioli DISTEF-G would be an interesting microorganism for useas a biocontrol agent.