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

MARIA DEL PILAR CARO; GABRIELA CONTI; M.G. MARTINEZ ZAMORA; JUAN CARLOS DIAZ RICCI; SEBASTIAN ASURMENDI

Foz de Iguazú

Congreso; International Plant Molecular Biology 2015; 2015

International Society for Plant Molecular Biology

AsES, a subtilisin like serine protease isolated from the avirulent fungusAcremonium strictum, provides total systemic protection against anthracnoseand gray mold diseases and induces defence-related genes expression instrawberry. Similar defence responses were observed in Arabidopsis, howeverAsES 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 itseffect 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 of antiviralresponsive genes that are involved in salicylic acid signalling (PR1, RDR1,WRKY70), ethylene signalling (ERF6), and hormonal crosstalk (DELLA-targetprotein bLHL137) in AsES and water treated plants, comparing TMV-Cginfected vs. non-infected. Viral titer was quantified by measuring CgCP (coatprotein) transcript levels.These results showed that AsES inoculation significantly reduced CgCPexpression level, evidencing virus defence enhancement. Also, AsES-treatednon-infected plants showed PR1 down-regulation and ERF6 up-regulation at120 h post-treatment (hpt), in agreement to previous results observed instrawberry. An increase in bLHL137 levels was also observed in AsES-treatedinfected plants. This work provides new insights into AsES mechanism of actionas well as sheds new light on a novel strategy for virus biocontrol.