ENDOPHYTIC COLONIZATION AND PLANT PROTECTION AGAINST Botrytis cinerea MEDIATED BY OXALIC ACID-DEGRADING BACTERIA

MEDINA AJ; ROMERO FM; ROSSI FR; GÁRRIZ A; GONZALEZ ME; PIECKENSTAIN FL; MARINA M

Congreso; XV Reunión de la Sociedad Argentina de Biología; 2013

Oxalic acid (OA) is a virulence factor produced by the phytopathogenic fungi Botrytis cinerea and Sclerotinia sclerotiorum. OA-deficient B. cinerea strains are hipovirulent and transgenic plants that degrade OA are more resistant to this fungus than wild-type plants. In this work, the existence of rhizospheric bacteria able to degrade OA and in turn endophytically colonize plants was evaluated, also analysing their potential for plant protection against B. cinerea. Two strains (OxA and OxB) able to use OA as the sole carbon source were isolated from rhizospheric soil. OxA and OxB inoculation on leaves of Arabidopsis thaliana demonstrated that they are able to endophytically colonize plants. In addition, colonization by OxA and OxB reduced leaf damage caused by exogenous potassium oxalate. Moreover, leaf colonization by these bacteria attenuated disease symptoms caused by B. cinerea infection. Thus, OxA and OxB strains are potential biological control agents of plant diseases caused by B. cinerea. Current work aims to the taxonomic identification of OxA and OxB and confirming that protective effects are mediated by OA-degradation.