Oxalate-degrading rhizobacteria colonize Arabidopsis and protect against B. cinerea infection

MEDINA, ANDRÉS J; ROMERO, FERNANDO M; ROSSI, FRANCO R; GARRIZ, ANDRÉS; GONZALEZ, MARÍA E; PIECKENSTAIN, FERNANDO L; MARINA, MARÍA

Chascomús

Congreso; XV JORNADAS ANUALES DE LA SOCIEDAD ARGENTINA DE BIOLOGIA; 2013

SAB

Oxalic acid (OA) is an important toxin produced by some plant necrotrophic fungus like Botrytis cinerea and Sclerotinia sclerotiorum. B. cinerea oxalate-deficient mutants showed lower infectivity than wild type strains and transgenic plants over-expressing OA-degrading enzymes were more tolerant to fungus infections. In the present work was investigated the existence of OA-degrading rhizobacterias that were able to colonize endophytically leaves, analyzing their capacity to protect Arabidopsis against B. cinerea infection. Two bacterial strains were isolated from the rhizosphere of tomato able to grow on oxalate as the sole carbon source. These strains (OxA and OxB) were inoculated in Arabidopsis leaves and could be demonstrated their capacity to survive as endophytes. In addition, the inoculation of Arabidopsis leaves with bacterial isolates caused a delay in the apparition moreover a reduction of the symptoms associated to oxalate treatment in Arabidopsis. In similar assays, Arabidopsis leaves inoculated with OxA or OxB, and then re-inoculated with B. cinerea spores showed a reduction in the area of the necrotic lesions caused by the pathogen. OxA and OxB seem to be as a potential agent of biological control against plant infections caused by B. cinerea. At present, there are carrying out the taxonomic identification of both bacterial isolates as well as studies to confirm the OA-degradation protective effect against B. cinerea infection.