COLONIZATION OF DIFFERENT CROPS BY THE PLANT GROWTH PROMOTING-BACTERIUM Burkholderia tropica

COUYOUPETROU, M.; MOYANO, D.; BERNABEAU, P.; GALAR, M.; TORRES TEJERIZO, G.A.; PISTORIO, M.; LUNA, M.F.

Puerto Madryn, Chubut, República Argentina

Congreso; XLVI Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2010

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

The use of biofertilizer and biocontrol organisms is being consideredas an alternative or a supplementary way of reducing the use ofchemicals in agriculture. These beneficial bacteria are able tocolonize roots and, some of them, are also able to colonize planttissues (endophytes). The understanding of bacterial colonizationpatterns is a critical prerequisite for the development of effectiveinoculants. In the present study, colonization patterns of the plantgrowth promoting bacteria Burkholderia tropica has beenmonitored by dilution plating assays and microscopic localization incrops of Lycopersicon esculentum, Brassica napus and Sorghumbicolor inoculated with this organism. Microscopic localization ofB. tropica (labeled with a stable plasmid carrying the gen for greenfluorescent protein) showed that seedling inoculation led toextensive root surface colonization in these plants. This is inaccordance with the high epiphytic population densities found in allplants tested (~6-7 log CFU/g fresh weight). Root endophyticbacterial enumerations were also similar for the different crops (~5log CFU/g fresh weight) and aerial tissues were colonized efficiently(~4 log CFU/g fresh weight). This study provides evidence that B.tropica is able to colonize other plants than its original host and alsoestablish stable associations, at least under our experimentalconditions.