AsES elicitor reduces TMV-Cg viral titer and induces expression of defence-related genes in Arabidopsis.

CARO, MP.; CONTI, G.; MARTINEZ-ZAMORA, MG.; DÍAZ RICCI, JC. ; ASURMENDI, S.

Foz do Iguazú

Congreso; 11th International Congress of Plant Molecular Biology Iguazú Falls (Argentina - Brazil); 2015

International Plant Molecular Biology

AsES, a subtilisin like serine protease isolated from the avirulent fungus Acremonium strictum, provides total systemic protection against anthracnose and gray mold diseases and induces defence-related genes expression in strawberry. Similar defence responses were observed in Arabidopsis, however AsES defence induction against a viral pathogen have not been tested yet. Moreover, isolation and purification of native AsES is highly inefficient and timeconsuming. The aim of this work was to express a recombinant AsES in order to evaluate its effect on TMV-Cg virus infection in Arabidopsis thaliana. AsES pro-protein CDS was cloned into pET-51b(+), expressed in Escherichia coli BL21(DE3) and then purified by affinity chromatography. Recombinant protein showed in vitro proteolytic activity and defence eliciting activity in strawberry mimicking effects reported for native AsES. In Arabidopsis, we evaluated by RT-qPCR the expression of antiviral responsive genes that are involved in salicylic acid signalling (PR1, RDR1, WRKY70), ethylene signalling (ERF6), and hormonal crosstalk (DELLA-target protein bLHL137) in AsES and water treated plants, comparing TMV-Cg infected vs. non-infected. Viral titer was quantified by measuring CgCP (coat protein) transcript levels. These results showed that AsES inoculation significantly reduced CgCP expression level, evidencing virus defence enhancement. Also, AsES-treated non-infected plants showed PR1 down-regulation and ERF6 up-regulation at 120 h post-treatment (hpt), in agreement to previous results observed in strawberry. An increase in bLHL137 levels was also observed in AsES-treated infected plants. This work provides new insights into AsES mechanism of action as well as sheds new light on a novel strategy for virus biocontrol.