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 avirulentfungus Acremonium strictum, provides total systemic protection againstanthracnose and gray mold diseases and induces defence-related genes expressionin strawberry. Similar defence responses were observed in Arabidopsis,however AsES defence induction against a viral pathogen have not been testedyet. Moreover, isolation and purification of native AsES is highly inefficientand time-consuming. The aim of this work was to express a recombinant AsES in order toevaluate its effect on TMV-Cg virus infection in Arabidopsis thaliana. AsES pro-protein CDS was cloned into pET-51b(+), expressed in Escherichiacoli BL21(DE3) and then purified by affinity chromatography. Recombinantprotein showed in vitro proteolytic activity and defence eliciting activity instrawberry mimicking effects reported for native AsES. In Arabidopsis, we evaluated by RT-qPCR the expression ofantiviral 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 bymeasuring CgCP (coat protein) transcript levels.These results showed that AsES inoculationsignificantly reduced CgCP expression level, evidencing virus defenceenhancement. Also, AsES-treated non-infected plants showed PR1 down-regulationand ERF6 up-regulation at 120 h post-treatment (hpt), in agreement toprevious results observed in strawberry. An increase in bLHL137 levelswas also observed in AsES-treated infected plants. This work provides newinsights into AsES mechanism of actionas well as sheds new light on a novel strategy for virus biocontrol.