Biological activity of the novel protein AsES in Arabidopsis thaliana against Botrytis cinerea

HAEL CONRAD, VERÓNICA; DÍAZ RICCI, JUAN CARLOS; MÉTRAUX, JEAN-PIERRE ; SERRANO, MARIO

Maringá

Congreso; VII Reunião Brasileira sobre Indução de Resistência em Plantas a Patógenos; 2014

Universidade Estadual de Maringá, Universidade Estadual do Centro-Oeste

AsES is a novel extracellular elicitor protein produced by an avirulent isolate of the strawberry fungus Acremonium strictum. Foliar spray with AsES provided a total systemic protection against anthracnose disease in strawberry, accompanied by the expression of defense-related genes, accumulation of ROS and callose. To help elucidating the mode of action of this new elicitor we determined its activity in the well-known genetic system Arabidopsis thaliana accession Columbia-0. The AsES protein used here was purified as described previously (Chalfoun et. al., J. Biol. Chem., 288:14098-14113, 2013). When 4-week-old A. thaliana plants were treated with 2 µg/ml of AsES 48 hours previous to B. cinerea infection (5x104 spores ml/1), symptoms after 2 days (measured as lesion size) were reduced by approximately 50% with respect to mock-treated plants. In vitro analysis showed that germination of the spores was not inhibited in the presence of increasing concentrations of AsES. This implies that protection to B. cinerea after AsES treatment was not due to a direct effect on spore germination but rather to induced plant defenses. These results are further supported by the findings that AsES affects differentially mutants impaired in the response to salicylic acid. These promising results make it possible to exploit the full potential of A.thaliana and its genetics to understand the molecular mechanisms triggered by AsES.